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System to Monitor the Level of Activity of People with Severe

1. AALBORG UNIVERSITY Department of Health Science and Technology May 2008 System to Monitor the Level of Activity of People with Severe Dementia Treated with Music Therapy 4th semester group 471 Mike Thagaard Hagelskj r Ann Sofie Holm Henriksen Carina Jensen Lasse Sohrt Petersen Steffen Vangsgaard M AALBORG UNIVERSITY Department of Health Science and Technology Fredrik Bajersvej 7 9220 Aalborg st Denmark Title System to Monitor the Level of Activity of People with Severe De mentia Treated with Music Therapy Topic Processing of Biological Signals Project period 4 semester spring 2008 Project group ST4 471 Participants Mike Thagaard Hagelskj r Ann Sofie Holm Henriksen Carina Jensen Lasse Sohrt Petersen Steffen Vangsgaard Supervisor Erika G Spaich Copies 8 Pages 135 Appendices 5 Finished 30 May 2008 ment is accepted Music therapists claim that music therapy has a beneficial effect on the wandering be havior of patients suffering from frontotem poral dementia This assertion is not veri fied by quantitative documentation This project deals with the design and implementation of a system to measure the activity level of the patients In the project there has been used a micro con troller which is programmed to record and filter the signal from an accelerometer and transmit it to a PC where the data is an alysed and visualised The system is com
2. Close COM port Voltage V Save Data Data Analysis 6 Time sec Autoscale Y RESET Figure 10 9 When the START button is pressed the GUI starts receiving data from the AP If the accelerometer is held correct the baseline of the curve will be approx 1 44 V and then varies depending on how the system is being moved The data which the ED has saved to flash is send to the AP when this is chosen The AP transmits the data to the PC and the data are visualised in the GUI which shows that the data has a baseline of approx 1 5 V and then swings depending on how the accelerometer is turned and shaked When the LOAD button is pressed the file which is named with the typed in civil registra tion number is opened The curve will then be plotted in the system of coordinates as in figure 10 9 It is also tested if the COM port is closed when the user presses the Close COM port button When the user chooses the Close COM port function the PC stops receiving data from the AP which indicates that the COM port is closed To test if the GUI is saving the data correctly which means that the variables which are being defined are in the file and that the file is named after the patient s civil registration number the Save Data button is pressed The test shows that the file is named and saved correctly and that it contains the defined variables 82
3. To fully analyse the complex activity of walking it has to be broken down into named parts It is necessary to consider both the temporal and the spatial components of gait The temporal components are those periods of time during which events take place and are often measured in seconds For example the period of time one foot is swinging through the air is called the swing phase The spatial components are the position or distance covered by the limbs eg stride length In gait analysis it is critical to examine both types of components because any abnormality can effect either The spatial components are illustrated in figure D 1 and the temporal components are illustrated in figure D 2 32 The Gait Cycle The gait cycle is the period of time during which a complete sequence of gait related events takes place Usually the gait cycle is considered at only one limb at a time Normally the cycle is measured from the heel strike of one foot continuing until the next heel strike from the same foot That is one complete stride but it could be measured from any given moment in the cycle 32 The gait cycle is divided into two phases The stance phase and 123 124 Appendix D Gait Left step length 4 Right step length J ge SS foot angle p Step width E A Right foot angle ad Stride length f Figure D 1 The spatial components of gait 12 the swing phase The two phases represents the periods of time where t
4. Figure E 3 Successive Approximation 42 In the ADC10 an ADC clock ADC10CLK is integrated The ADC10CLK is used as the conversion clock and to generate the sampling period During the conversion it is important that the ADC10CLK remains active since the operation can not be completed if the clock is removed and the result will be invalid Figure E 4 shows the sampling and converting time 22 Start Stop Start Conversion Sampling Sampling Conversion Complete H f SAMPCON 13 x ADC10CLKs 4 sample Pi tconvert tsync Figure E 4 The figure shows the sample timing 22 When sampling the sample frequency has to be selected according to the Nyquist theorem which is fs gt 2 Fmax E 2 130 Appendix E MSP430f2274RHA If the sampling frequency is the same as the frequency of the signal it looks like the signal is a DC voltage see figure E 5a If the sampling frequency is 3 of the signal the result can be different from the wanted signal see figure E 5b If the sampling frequency follows the Nyquist Theorem the result will be a signal with no aliasing errors see figure E 5c WAN V ANNA y J Sampled at 4 3 kA F YY Y Figure E 5 Overview of how the sampled data depend on the sampling frequency Flash Memory The flash module of the MSP430f2274 has a controller that controls erase and programming operations The size of the flash memory is 32KB 256B where the 32KB i
5. on rn nn 4 2 Music Therapy and Dementia CC Comm 5 Problem Statement 5 1 Synthesis of Problem Analysis 22 2 oo Emm nn II Problem Solving 6 System Requirements 6 1 Functional Requirements 2 a a a 6 2 Other Requirements 7 Methods to Measure Level of Activity 1 1 Pedometer sr e ne RO OR e at a ee 1 2 Goniometer s a aa a aus a 7 3 Force Sensing Resistor nn nn 7 4 Global Positioning System 2 0 20 00 nn 7 5 Electromyography 2 0 0 1 6 Accelerometers tsi en a OS Rw eee Ae 7 7 Selecting a Method of Measurement 2 0004 8 Specifications 8 1 Hardware Specifications ooa a ee 8 2 Software Specifications 2 2 ee 8 2 1 User Requirements 22 2 CH Eon 82 2 Use Cages o ea ra GP en Qo D RA RADE vi 11 11 11 13 13 15 17 17 17 19 19 20 20 21 21 21 22 vi 8 2 3 End Device 4 2 2 Aon si A a Pe Ann Ba ai 28 8 24 Acc s Point Cenon ar srl ee oe a Beek 30 8 2257 Matlab 2 ru ae rar 2 Sante Seen m nn US a ee at 31 8 3 Accept Test of the Hardware nn nn 33 8 3 1 Regulator 2 aSa pi a ei Fr es a hes a O 33 8 3 2 Evaluation Board Accelerometer o 33 8 4 Accept Test Software CE nn nn 34 8 4 1 Functional Requirements o 34 8 4 2 User Requirements sonata dt 2 Daran can 34 9 Design and Implementation 37 9 1 Hardware Design 2 2 2 ee 37 9 1 1 Power
6. pact and intended to be placed on the ankle of the patient With the system it is possible to detect the gait events heel strike and toe off thus de termining the swing stance ratio The user of the system can manually compare data before during and after a music therapy session to see the changes in the gait The system has not been verified with pa tients suffering from frontotemporal de mentia but has been tested on a healthy subject The system fulfilled the technical and functional specifications which means that the system is capable of measuring the activity level There is free access to the contest of the report though no reference publications without the authors agree Preface This report has been made by group 471 4 semester at the Department of Health Science and Technology at Aalborg University The project period lasted from the 4 of February to the 30 of May 2008 The main theme of the semester is Processing of Biological Signals In the project period methods to collect process and present the signals collected from the body in preparation for diagnosing treating or rehabilitation is studied The target group of the project is students and supervisors at the Department of Health Science and Technology at Aalborg University and other interested The group would like to direct special thanks to John Hansen Strahinja Dosen and Jan Stavnshgj for technical support Furthermore the group
7. sure how fast and how powerful the patients are walking only the number of steps On some patients it can be difficult to place the sensors which are a big problem If the patient does not want any help on the morning toilet the staff is letting them do it on their own This makes if difficult to find an opportunity to place the sensor without the patient noticing This will change from patient to patient how difficult it will be to place the sensors It could be an idea to place the sensors on the legs or on the back since it is difficult to reach for the Appendix B Interview 107 patients To determine the physical activity of the patient it would require measurement both day and night in order to register if music therapy make the patients more active at night which would not be the intended effect of the therapy The effects of music therapy which are seen after an ended session are called the carry over effect The present method for register ing restless behavior is a questionnaire by the staff the CMAI Cohen Mahnfiels Agitation Inventory It may be difficult to make the staff complete the questionnaires as the staff is already under a lot of time pressure which makes the questionnaires very vulnerable The use of questionnaires may be connected to sources of error The staff might have experienced difficulties in evaluating whether the patients are more or less relaxed Furthermore does the staff of the care center not work 24 hours
8. Save Data Data Analysis RESET and EXIT The functions will be elaborated in the fol lowing LOAD Before the user uses the LOAD function it is necessary to type in the name and the civil registration number of the patient The LOAD function uses the civil registration number to get the file which is saved under that name The file is being plotted in the system of co ordinates where the name and the civil registration number of the patient stand above the system of co ordinates Choose COM port Before the data collection is started the user has to choose which COM port the uC is using This is done by a script which shows all the available COM ports on the computer START The START function starts showing the typed name and civil registration number above 68 Chapter 9 Design and Implementation Figure 9 21 The flowdiagram of the GUI The user starts to type the patients name and civil registration number Afterwards it is possible to choose between two different modes LOAD and START which will lead the user in two directions The START function opens the COM port and receives data from the wC When the data collection is finished the user has to close the COM port which will make it possible to zoom at the graph The user can now choose to save the data and make data analysis afterwards or make the data analysis and then saving it If the user from the beginning choose to LOAD data it will be possible to do data analysis a
9. Velocity Decreases Range of ankle movement Decreases Toe clearence Decreases Table D 1 Age related Changes in Gait 32 Appendix E MSP430f2274RHA Microcontroller In this project the eZ430 RF2500 Development Tool is being used The eZ430 RF2500 is used to make the system wireless so the patient can walk around freely The AP and ED are identical but can contain different kinds of code The ED and AP contain the uC MSP430F 2274 the CC250 2 4 GHz wireless transceiver two LEDs a push button a chip antenna and 18 pins The USB powered part contains an USB plug and a MSP430 Applica tion UART which the eZ430 RF2500 uses to send and receive data from a PC Figure E 1 shows the eZ430 RF2500 Spy Bi Wire amp Pushbutton 2X LEDs MSP430 Appliation UART cc2500 hip Antenna USB Powered MSP430F2274 18 Accessible Pins Figure E 1 The eZ430 RF2500 where the USB powered part is to the left and the AP which is similar to the ED is to the right The uC is a ultralow powered device and one of the main power advantages is that the uC can wake up from standby mode in less than 1 us and thereby save power when it is in low power mode expanded later in this chapter The uC has a supply voltage range from 1 8 V to 3 6 V and a low current consumption When it is in active mode it has a current consumption of 270 yA in standby mode 0 7 yA and in off mode it has a current consumption of 0 1 yA The uC has 32KB 256B flash
10. 9 12 the self test is illustrated in a flowchart ES ithin expect Figure 9 12 Flowchart for ED self test The self test is only activated when the system is in pushbuttonmode 2 If this is the case AO will be defined Next it will be decided whether AO is above or below the expected limits If the test is positive the green LED will be on if the test is negative the red LED will be on The function will test whether the battery uC and accelerometer are connected and ini tialised correctly The test is performed continuously while pushbuttonmode is equal to 2 in the following code while pushbuttonmode 2 9 3 Design and Implementation of Functions on End Device 53 AO msg counter if AO lt 127 amp amp AO gt 122 if BSP_LED1_IS_ON BSP_TOGGLE_LED1 BSP_TOGGLE_LED2 else if BSP_LED2_IS_ON BSP_TOGGLE_LED2 BSP_TOGGLE_LED1 After entering the while loop the result from the A D conversion is copied into the variable AO The if loop decides whether AO is within expected limits If AO is within expected limits the red LED will turn off and the green LED will turn on to indicate a successful test A successful test is if the accelerometer is placed plane and the same time is held still If this is not the case the green LED will turn off and the red will be turned on The values which set the limits are 122 and 127 122 and 127 are the same as 488 and 508 after bei
11. Data to Flash When an interrupt is received from the push button pushbuttonmode will now be equal to 4 and the following while loop will be entered while pushbuttonmode 4 __bis_SR_register LPM1_bits __disable_interrupt FCTL1 FWKEY WRT Flash_ptr msg 0 b FCTL1 FWKEY __enable_interrupt if b 2100 pushbuttonmode In the loop the program will start to make the uC enter low power mode 1 with interrupts enabled The loop will continue after an interrupt from the ADC10 interrupt service routine is received and then all interrupts are disabled This ensures no unexpected events to happen that could interfere with saving in flash memory The Flash Memory Control Register 1 FCTL1 is initialised and FWKEY and WRT are set FWKEY is the password which must be set before it is possible to perform changes in the register WRT enables write mode and thereby makes it possible to write in the flash memory Flash_ptr msg 0 writes the sample which is temporarily stored in array msg on place 0 to place in flash where Flash_ptr 1 points to In this case Flash_ ptr points to OxXAA10 and the sample will therefore be written on place OxAA11 in flash memory This procedure is repeated 10 times not shown in the code to write the entire array msg to the flash After these procedures the variable b is incremented In Flash Memory Control Register 1 the password is now set and thereby the
12. SUCCES SMPL_ Send Furthermore it can be concluded that the data trans mission time is approximately 3 7 ms To obtain a system that functions optimal regarding current consumption and execution time of functions the baud rate of the radio should be adjusted to meet the wanted requirements Appendix D Gait One of the objects of this project is to measure the amount of harmful wandering of the de mentias quantitatively To do this a number of topics have to be reviewed In this chapter the terminology of gait the change in gait as a result of aging and the possibility for gait analysis will be reviewed Walking is a complex highly energy efficient method of progression utilising rhythmical reciprocal movements of the lower limbs where one foot is always in contact with the floor People normally walk for the purpose of getting from one point to another But increasingly walking has been proven a safe and effective way of maintaining fitness particularly in the later years of life thus emphasising the need for analysis to differ between beneficial and harmful types of walking In science and health care professions the term gait is often used in preference to walking 32 The general definition of gait is the pattern style or manner of walking Gait analysis is a branch of biomechanics which is the application of Newtonian mechanics to the study of the neuromuscular skeletal system 23 The Gait Cycle and Terminology of Gait
13. Supply 202 act AM ae ee he a Ae 37 9 1 2 Accelerometer 2 on nn rn 37 9 1 3 Evaluation Board s s a soe nn on nn 41 9 2 Software Design ton a She far en ea a ep ea els er a 43 9 21 End Device A O E Oe a GBs a a 43 9 2 2 Access Point s d cn ns ae ie JA ae A A A 45 9 2 3 Graphical User Interface in Matlab 0 46 9 3 Design and Implementation of Functions on End Device 48 9 4 Design and Implementations of Functions on Access Point 60 9 5 Data Analysis 4 er A he DA Be a a a 62 9 6 Design of Graphical User Interface 2 22 CE rn nn 67 10 Test of the System 71 10 1 Test of the Hardware u 22 Dace BG ae oR aks Gh Gak aan 71 10 2 Test of the Software sec 6 0 a 8 eth na ar a a 74 11 Test of the Entire System 83 101 Methods rs he on ME ORS AAA oe ee we ee 83 11 2 Results 200 5 oe dhe Swe bao e Sad bb eS ee eee ee Be 84 III Summary 89 12 Discussion 91 13 Conclusion 95 14 Future Perspectives 97 Bibliography 99 A Interview Guide 103 B Interview 105 vill Contents C Pilot Experiments C 1 Pilot Experiment 1 Accelerometer Saturation Test C 2 Pilot Experiment 2 End Device Max Range C 3 Pilot Experiment 3 Mechanical Noise C 4 Pilot Experiment 4 Package Loss over Distance C 5 Pilot Experiment 5 Gait Event Identification C 6 Pilot Experiment 6 Radio Activity Effect on Voltage Reference D Gait E MSP430f2274RHA Chapter 1 Introduction Patients
14. To ensure that ADC10SC is placed in ADCIOCTLO without overwriting the previous setup the bitwise OR assignment is used Configuration of Timers 1 TACCTLO CCIE 2 TACCRO 57143 3 TACTL TASSEL_2 4 TACTL MC_1 Line 1 the capture compare interrupts CCIE are enabled in timer A capture compare control register 0 TACCTLO Line 2 TACCRO is the capture compare register 0 in which the number 57143 is set since the desired sampling frequency is 70 Hz Line 3 the source of timer A defines timer A This property is set in TACTL which is the control register of timer A The command TASSEL_ 2 chooses the clock source which in this case is the sub main clock The frequency of the sub main clock is set to 4 MHz in 9 3 Design and Implementation of Functions on End Device 49 the configuration of the basic clock module in subsection 9 3 line 5 The reason for doing this is to slow down the process that counts to TACCRO in order to obtain a more precise sampling frequency Line 4 the timer A is set in up mode Thus the timer A starts counting up to TACCRO i e 57143 with a frequency of 4 MHz This produces a frequency of 70 Hz which is used as the sampling frequency in the ADC Timer B is not used in this project 21 22 Configuration of the Basic Clock Module To control the performance of the modules in the wC the basic clock module has to be configured 1 BCSCTL1 CALBC1_8MHZ 2 DCOCTL CALDCO_8MHZ 3 B
15. an access violation to the flash memory occurs or an edge on the reset NMI pin in NMI mode Interrupts caused by peripherals are the maskable interrupts System reset interrupts are the ones with the highest priority and are generated by power up external reset watchdog flash password og illegal instruction fetch When an interrupt occur the CPU completes the currently executing instruction then accepts the interrupt and saves the status for the program which was being handed when the interrupt entranced If there is more than one interrupt the one with the highest priority is performed Operating Modes Since the uC is made for ultra low power consumption it can operate in six different operating modes The six modes are active and low power mode 0 4 In active mode the CPU and all the enabled clocks are active In LPMO 4 the CPU and main clock is disabled and 134 Appendix E MSP430f2274RHA depending on which mode there is chosen the other clocks can be enabled or disabled When an interrupt occurs the wC wakes up from any of the low power modes CC2500 2 4 GHz Radio Frequency Transceiver The two eZ430 RF2500T target boards each contain a CC2500 2 4 GHz Radio Frequency Transceiver as an IC integrated circuit The CC2500 is connected to a 50 2 antenna via a number of external resistors inductors and capacitors The CC2500 is driven on the same power supply as the wC ranging from 1 8 V 3 6 V 6 of the pin outs of the CC2500 IC ar
16. dementia are recognizing the songs and the music therapist which sooths the patient The patient sometimes starts the session with restless wandering but often the patient will sit down next to the therapist and sometime falls asleep Patients with severe dementia receive sessions on a daily basis but patients suffering from a milder form of dementia it may be enough with one session a week To indicate the effects of music therapy music therapist Hanne Mette Ochsner Ridder has measured some of the patient s heart rate In this study heart rate were measured at the same time every day one week prior to the music therapy Afterwards the patient received music therapy for four weeks and 5 times a week and during the sessions the heart rate were measured For a week after the last session the heart rate was measured again and shoved significant fall in heart rate This test has only been performed in a single case design on six patients If the effects should be scientifically proven the test has to be performed on more patients which are very time demanding Another study has been made where the patients wore a pedometer to measure their level of activity During the study the main problem was that the patients removed their pedometer Some does not notice it while others do It is important that the equipment being used is cheap because of the risk of being destroyed by the patient That is why pedometers are good Unfortunately the pedometer cannot mea
17. dual axis accelerometer adxl311 http www analog com UploadedFiles Data_Sheets ADXL311 pdf 2005 Vaughan et al Dynamics of Human Gait Kiboho Publishers second edition 1992 Bloom et al Floyd E The Dana Guide to Brain Health Dana Press 2006 Florida Association for Music Therapy Healing hearts through harmony http www floridamusictherapy com Manji Hadi Oxford Handbook of Neurology Oxford University Press 2007 Harder et al Henrik Experiences from gps tracking of visitors in three public parks in denmark based on gps technologies Videnbasen 2008 99 100 Bibliography 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 Freelance Illustration and Graphics Regions of the human brain http www science ca images Brain_Witelson jpg Picture Texas Instruments Accelerometers and how they work http www2 usfirst org 2005comp Manuals Acceler1 pdf 2005 Texas Instruments Cc2500 http focus ti com lit ds symlink cc2500 pdf 2007 Texas Instruments ez430 rf2500 development tool user s guide http focus ti com lit ug slau227a slau227a pdf 2007 Texas Instruments Data sheet for msp430x22x2 msp430x22x4 http focus ti com lit ds symlink msp430f 2274 pdf 2008 Texas Instruments Msp430x2xx family user s guide rev e http focus ti com 1it ug slaul44e slaul44e pdf 2008 Griffiths Iwan W
18. etc 6 1 Functional Requirements e The patients level of activity shall be registered e Because the patients can walk around during the night the system must be able to register in a 24 hour period of time e It is not expected that the staff have technical literacy therefore the system must be easy to handle 6 2 Other Requirements The system e has to be placed out of immediate reach of the patients since the patients tend to remove unfamiliar objects e has to be low cost since the patients tend to hide or destroy unknown objects e has to be low weight so it does not annoy the patient e has be robust since the patients tend to hide or destroy unknown objects 17 18 Chapter 6 System Requirements e has to be safe to the patient without any risk of electrical shock e has to be possible to construct the system within the period of the project The primary goal in this project is to develop a system that should be able to measure the patients activity level in a 24 hour period The developed system has to be small low weight and able to be placed where it does not attract attention from the patients 1 Chapter Methods to Measure Level of Activity In order to determine the level of activity in patients suffering from dementia different methods have to be considered A lot of physiological changes happen when e g change of gait occurs or when ones mood changes There are several methods availab
19. front of the radio When the Matlab script was running the button on the ED was pushed and the ED sent the numbers from zero to 255 Matlab received the data and from this the number of lost data could be counted The number of lost data was plotted to evaluate the result First the wC was held with the front of the radio towards C 4 Pilot Experiment 4 Package Loss over Distance 115 the AP and afterwards the back of the radio was pointed towards the AP Three different amplifications were tested 12 dB 0 dB and 1 dB To configure the CC2500 transceiver a software tool SmartRF Studio from Texas Instruments was used This tool allows easy evaluation of all RF ICs from Texas Instruments including the CC2500 Results In figure C 6 the results from the first experiments when the front of the radio was pointed towards the AP can be seen The black line represents the 12 dB amplification which at a distance at 5 meters could not connect to the AP The 0 dB and 1 dB amplification could connect and send the data up to ca 24 meters Loss of Data front 0 dB dB 12 dB Loss of Data in 25 Distance in Meter Figure C 6 At the figure the package loss in percent is shown It shows the three different amplifications which were used in the experiment At the 0 dB amplification there is a substantial loss of package but at 1 dB amplification the loss of packages is less th
20. have been received from the accelerometer or the battery is empty All desired data have been received 30 Chapter 8 Specifications Transmit Data Scenario I Transmit collected data to the AP when all desired data have been received Scenario II Transmit data live to the AP Scenario I 1 All desired data have been received 2 Connection to AP succeeds 3 Transmit data from flash memory to AP includes Save data to flash memory Exceptions No data have been received from the accelerometer or the battery is empty The AP is out of reach not connected to the PC or have lost power after ED has been activated Scenario IT 1 Connection to AP succeeds 2 Transmit data to AP Exceptions Equal to the exceptions in scenario I 8 2 4 Access Point MSP430f227 4 End Device 2 Matlab 2 Includes Figure 8 5 The use case diagram for AP 8 2 5 Matlab 31 Receive Data Receives data from ED Scenario 1 Find and recognise the ED 2 Receive data from the ED Exceptions No signal from the ED No data received by ED Transmit Data Transmits data received from ED to Matlab Scenario 1 Get data from ED Includes Receive Data 2 Transmit data to Matlab Exceptions The AP is not connected to the computer or there is no available data to transmit 8 2 5 Matlab MSP430f2274 Acces Point User Includes Figure 8 6 The use case diagram for Matlab 32 Chapter 8 S
21. in such a typical stride is detected with a two sample delay and the toe off and the succeeding heel strike is detected with only a one sample delay this will give an imbalance in the swing stance ratio The difference of one sample will give a stride duration of 89 samples and stance phase with a duration of 53 samples This gives a swing stance ratio of 40 45 59 55 The deviation from the typical stride that was registered correctly is 0 75 9 6 Design of Graphical User Interface 67 9 6 Design of Graphical User Interface The purpose of the Graphical User Interface GUI is to simplify the use of the software It is required to have Matlab installed on the computer but the uC does not have to be connected to the computer if there is being loaded exclusively old data The GUI is shown in figure 9 20 COM3 v Enter Name Enter civil registration number START Close COM port Voltage V 5 of Save Data Data Analysis MN Autoscale Y Time sec RESET Figure 9 20 The figure shows the GUI which consists of seven push buttons LOAD START Close COM port Save Data Data Analysis RESET and EXIT two interactive fields Enter name and enter civil registration number a pop up menu Choose COM port and a system of co ordinates Figure 9 21 shows the flowdiagram for the GUI The GUI contains eight functions LOAD START Choose COM port Close COM port
22. location and size of the SG110 A makes it possible to measure the activity level of the patients The price of about 5600 DKR for the SG110 A is however a drawback 31 2 7 3 Force Sensing Resistor Force Sensing Resistors FSR consists of a polymer thick film that converts an increase in applied force to a decrease in resistance The force sensor available is the FlexiForce A201 100 from TexScan The diameter and thickness of the sensing area of the sensor are 0 95 cm and 0 21 mm respectively The FlexiForce A201 100has a lifetime of 10 000 000 cycles The length of the sensors are 203mm 152mm 102mm and 51mm The cost of the sensors are 99 for eight sensors 45 By placing the force sensor under the foot of the patient it will be possible to register when the patient place weight on that foot i e when the patient is walking The benefits of the force sensor when used on the patient group are e The sensor is small and can be adjusted to fit the patient e Easy to place under the foot using double sided tape or inside a shoe e The sensor is inexpensive considering its lifetime e The sensor is placed under a foot making it difficult for the patients reaching and removing it The output of the sensor can be visualised as a graph where the resistance is shown over time with a peak each time pressure is applied to the sensor By analysing the graph it will be possible to calculate the time between each step i e if a patient is movi
23. loss of nerve cells in the brain results in loss of memory Memory loss is a common symptom of dementia but memory loss itself is not equal to dementia 40 7 8 Chapter 3 Dementia The symptoms change with the kind of dementia the patient suffers from In this project the focus will be on patients who tend to wander 1 The kind of dementia in which this symptom most often occurs is frontotemporal dementia In the following there will be an explanation of this type of dementia 3 2 Frontotemporal Dementia The frontal lobes are the part of the brain where the personality is generated and is located at the front of the brain see figure 3 1 Regions of the Human Brain Temporal Lobe y Cerebellum Front Back Figure 3 1 The structure of the brain 17 Frontotemporal dementia also called Pick s disease is a brain disease which especially affects the frontal lobe and the temporal lobes Frontotemporal dementia is the fourth most frequent cause of dementia and patients suffering from this make up for 5 10 of the dementias 39 26 15 Frontotemporal dementia occurs in the age of 35 70 and affects men and women equally 39 15 Patients suffering from frontotemporal dementia often get a personality disturbance start wandering may behave different and often their ability to speak is affected Some patients become unable to say anything but a word or two while others speak fluently but without content The change in person
24. of packages 118 Appendix C Pilot Experiments C 5 Pilot Experiment 5 Gait Event Identification Objective The objective of the experiment was to identify the gait events heel strike toe on heel off and toe off in the acceleration signal By identifying these events it would be possible to determine the phases swing phase stance phase foot flat and pre swing see appendix D A second objective was to determine the corner frequency and the stop band frequency of the digital filter Furthermore it was wanted to determine the sampling frequency F s on the background of the filter specifications Materials e Accelerometer e ADC e Computer e ScopeLogger e Matlab e Force Sensing Resistors Procedure The gait events was identified by measuring the acceleration of the ankle and the ground reaction forces simultaneously To measure the ground reaction forces a simple system consisting of two force sensing resistors FSR was created Each FSR was implemented as the variable resistor in a Wheatstone bridge The input voltage was supplied with a battery and the output voltage corresponding to force was sampled simultaneously with the acceleration signal One FSR was placed on the right heel of the subject and the other was placed distally on the right great toe of the subject The accelerometer was placed on the right ankle of the subject The subject walked about 10 meters and the signal was recorded Results The result
25. pC 2 See alarm that indicates an error 8 4 2 User Requirements The user requirements are tested as follows The system should be able to work on the MSP430f2274RHA uC 1 Start up the system on the MSP430f2274RHA 2 Test the individual functions and the entire system These tests will be further ex plained in section 10 2 Matlab should be used for the graphical user interface on the computer 1 Confirm all functions operates correctly 8 4 2 User Requirements 35 The size of the program has to be as small as possible with a maksimum of 32 kB 1 Check up on the size of the program by creating a memory map in IAR Embedded Workbench IDE 2 Confirm that the size of the program is under 32 kB The system should be able to read data from an accelerometer 1 Connect the accelerometer to the uC to check the connection between them 2 Connect the accelerometer and uC to power supply 3 Observe the uC has received data from the accelerometer The system should be able to save data on ED 1 Configure the system to save to flash memory 2 Input signal on ED 3 Get saved data from ED Chapter 9 Design and Implementation In this chapter the design and implementation of the modules in the hardware and the software will be described In the first section the hardware will be described and in the following section the software 9 1 Hardware Design The analogue circuit consists of a power supply an accelero
26. resulting in an abrupt deceleration of the foot known as heel strike At this moment the other limb is also in contact with the floor giving the state of double stance At this point the whole body centre of gravity is at its lowest and the subject is most stable e Foot Flat Immediate after the heel strike the stancing limb receives the total weight of the body To achieve this the foot rapidly has to change its position from dorsiflex ion that allowed the heel strike to plantigrade At plantigrade the whole foot comes into contact with the floor allowing it to carry the weight of the subject thus the term foot flat or loading phase e Mid Stance During mid stance the whole body centre of gravity of the subject is carried over the stance limb as the other limb is in the swing phase e The Propulsive Phase In the propulsive phase several events happen in rapid succession in order to propel the body forward and end the stance phase Initially the heel lifts up from the floor known as heel off This event is passive in slow gait but can require some muscle activity in faster gaits The next event is known as the push off In push off the calf muscles contract resulting in planter flexion of the stancing foot towards the floor thus pushing the foot off the floor This leads to the final event of the stance face toe off Ass the toes leave the floor the propulsion ends and the swing phase initiates 32 The Swing Phase During the sw
27. samples that is 1 70 s to 1 35 s This will not have an effect on the number of strides counted but it will provide an equally marginal decrease of the stance phase and an increase of the swing phase To identify the heel strike a threshold is set in Matlab See tresholdHS in figure 9 17 When the value of the acceleration signal is below the threshold it is compared if each value is lower than the successive value If the successive value is higher than the current value the current value must be a peak and is interpreted as the heel strike When the lowest value succeeding the threshold is found one stride is registered by incremented the value STRIDE the point of heel strike is registered by assigning HS stride with a value corresponding to the sample number Finally 21 samples are jumped ahead and the loop is exited The jump of 21 samples is found from analysing the signal and deciding how many samples which are convenient see figure 9 18 Identifying Toe Off In appendix C 5 the toe off has been identified in the acceleration signal The toe off is tak ing place between negative peaks followed by a positive peak see figure 9 17 Identifying the toe off as the positive peak will provide a marginal delay to the detected toe off compared to the actual toe off 1 2 samples that is 1 70 s to 1 35 s This delay will counterbalance 64 Chapter 9 Design and Implementation Figure 9 18 The figure shows the data flow of the loop
28. so it easy to find the patient again To be sure of the program would not overwrite exciting data the user should add an a to the 9 6 Design of Graphical User Interface 69 civil registration number when the data collection is from before a music therapy session b when it is from during a session and c when it is from after a session Data Analysis When the data collection is done the data analysis can begin The function counts the steps heel strikes and toe offs from the data From these informations the cadence and the swing stance ratio is calculated The user can then manually analyse the data RESET It is possible to clear the graph and remove the name and civil registration number above the system of co ordinates by clicking the RESET button EXIT At anytime it is possible to close the GUI by pressing EXIT A box will appear where the user has to confirm if the GUI should be closed or not Chapter 1 0 Test of the System 10 1 Test of the Hardware The purpose of testing the analogue circuit is to determine the functionality of the voltage regulator to ensure a stable voltage supply for the accelerometer and to validate the output of the accelerometer Test of the Voltage Regulator The functionality of the voltage regulator was tested by measuring the voltage level in the circuit in two locations at the input pin of the voltage regulator and at the output pin of the voltage regulator One measurement was carrie
29. standard of the patients is found through articles and an interview with a music therapist The summary of the interview can be seen in appendix B and the interview guide in appendix A During the interview answers to the following questions are pursued e Which types of dementia have tendency to lead to restless wandering e Which effects do music therapy have on the general activity stress level and the sleep cycle of the patient e How does the music therapist determine the effects of the music therapy if the patient is unable to speak As mentioned in this section it is necessary to get a knowledge about the patients suffering from dementia Therefore the next chapter will deal with dementia in general and afterwards the type of dementia identified through the interview Chapter 3 Dementia 3 1 Dementia in General Dementia is defined as a syndrome of progressive impairment of two or more areas of cogni tion sufficient to interfere with work social functions or relationships 15 Dementia is most often seen in elderly people but it cannot be included as a part of the aging process as it can affect people of any age 4 Dementia is usually not easy to diagnose in the beginning Often it can be difficult to decide whether the syndrome is present or not but after a while it becomes clear that the patient requires care 37 It is possible to identify cases of dementia by using several tests for instance the Mini Mental State
30. the filter in the ED port P4 3 is toggled while the filter function is executed The execution time is obtained on an oscilloscope and can be seen in figure 10 5 76 Chapter 10 Test of the System Figure 10 3 The figure shows the execution time of the function SMPL_SUCCESS SMPL_Send It can be seen that the time consumed is 3 6 ms Figure 10 4 The figure shows the execution time of the function save to flash memory It can be seen that the time consumed is 178 us 10 2 Test of the Software TT Figure 10 5 The figure shows the execution time of the filter on a single sample It can be seen that the time consumed is 74 4 us Read from Flash Memory To test the time consumed to read from flash memory port P4 3 is toggled while reading from flash memory The time port P4 3 is high can be obtained on an oscilloscope and seen in figure 10 6 On figure 10 6 it can be seen that the time consumed on reading from flash memory is equal to 15 7 us Figure 10 6 The figure shows the time consumed to read from flash memory The amount of data is 10 samples or 10 bytes It can be seen that the time consumed is 15 7 us 78 Chapter 10 Test of the System Based on the four previous tests it is concluded that the time period between each sample is long enough for other functions to execute without any complications This can be concluded based on the following calculation SMPL SUCCESS SMPL_ Send Savetoflash Filter
31. the push button connects the ED to the AP The second interrupt initiates the ED self test The third interrupt starts the data collection and send the data continuously to the PC The fourth interrupt stops the flow of data to the AP and saves data to flash instead The fifth interrupt is used when 5 min of data have been collected After 5 min an interrupt makes the wC enter low power low where it waits for the sixth interrupt When the sixth interrupt have been received ED transmit all collected data to the AP 9 2 2 Access Point 45 Save Data in Flash Memory This function saves data from ADC10 in flash memory on ED Transmit Data to Access Point This function transmits all data saved in flash memory to AP This function is performed when all data has been received 9 2 2 Access Point The main objective of the AP is to receive data from the ED and transmit this data to Matlab In figure 9 10 the processes in the AP are illustrated In the following an overview of the modules in the AP is given see figure 9 10 sJoinSem sPeerFrantaSem Figure 9 10 The processes in the AP The arrows indicates the direction of the data flow The flow will go through the sJoinSem aphore if a link request is sent from the ED The flow will go through the sPeerFrameSem aphore if the AP has received data from ED 46 Chapter 9 Design and Implementation Initialise Micro Controller This function performs initialisations for the uC These i
32. the range of 1 35 Hz was attempted The different filters can be seen in figure C 9a C 9c C 9b and C 9d Based on these studies it was found that a low pass filter with a corner frequency of 20 Hz and a stop band frequency of 34 Hz as in figure C 9d effectively simplified the signal without reducing the characteristic peaks When the highest frequency of the wanted signal is at 34 Hz Nyquist Theorem states that the sampling frequency must be at least twice as large Therefore the sampling frequency must be at least 68 Hz Conclusion By using simple Matlab algorithms the gait events heel strike and toe off should be readily detectable in the X axis of the acceleration signal thus determining the swing phase and the stance phase therefore it is chosen just to analyse at the X axis The events toe on and heel off are not visually detectable in the acceleration signal and it will not be an objective to detect these events in this project The corner frequency and the stop band frequency of the digital filter will be set to 20 Hz and 34 Hz respectively The sampling frequency is chosen to 70 Hz 120 Appendix C Pilot Experiments 10 Hz 20 Hz 20 Hz 25 Hz Kaxis 3 al AN NA DK Pr YW OP use a LS Xaxis Samples Samples 5 15Hz 20 34Hz 20 Hz 34 Hz 02 J 225 TER J y mll i We 02 0 4 4 15 06 o En 500
33. toe off and therefore a stride is lost and the system is not able to calculate the correct number of strides This can be caused by a too low sampling frequency hence if the peak occur between two samples the system does not register it It can also be caused by the fact that the signal is filtered before it is sampled If the bandwidth of the evaluation board has been set too narrow some high frequency signal could be lost Threshold Values The data analysis which is performed in the current system measures the heel strikes the toe offs and the swing stance ratios To measure heel strikes and toe offs two threshold values have been defined The threshold values are constant and defined from a test that Chapter 12 Discussion 93 has been made on a subject from the group who has a normal gait In appendix D it is described that the gait changes as people get older The system is tested on a healthy young subject and the threshold for heel strike and toe off is defined from tests with the subject Thus if the system is going to be used on an elderly person the threshold would not be the same and therefore the system can have problems finding the heel strikes and toe offs and thereby finding the swing stance ratio A solution could be to set the threshold as a variable the user could decide The program should have a threshold as default which means that it should be set as the one it has been tested with and then it should be possi
34. used with the next input and then put in temp counter for sending The x values are likewise put in an array on the second place In the filter equation the previous two values for both x and y are being used so every time a new value is being put into the array the previous is being pushed left one place ADC10 Interrupt Service Routine The following function is called each time an interrupt from ADC10 is received pragma vector ADC10_VECTOR __interrupt void ADC10_ISR void temp counter unsigned char ADC1OMEM gt gt 2 tmp counter signed char y 2 counter if counter 10 for counter 0 counter lt 10 counter msglcounter tmp counter counter 0 __bic_SR_register_on_exit LPM1_bits 9 3 Design and Implementation of Functions on End Device 59 The interrupt flag ADC10IFG from the ADC10 is set when a conversion result is saved in ADC10MEM The interrupt flag will automatically be reset when entering the ADC10 interrupt service routine The result from the A D conversion is located in ADC10MEM The result is bit shifted two to the right 2 this is done since the COM port is unable to receive 10 bits and saved as an unsigned char in the array temp to make values go from 0 to 255 The place in the array is initialised to place 0 and the counter incrementation will make sure that the entire array is filled Each value in the array temp is evaluated by the filter see section 9 3
35. value If the successive value is higher than the current value the next value is examined If the successive value is lower than the current value the current value must be a peak and is interpreted as the toe off When the highest value succeeding the threshold is found the point of toe off is registered by assigning TOFF h with a value corresponding to the sample number i To exit the loop 3 samples are jumped ahead If no toe off is registered between HS h and HS2 h TOFF h is assigned the value zero See figure 9 19 9 5 Data Analysis 65 Figure 9 19 The figure shows the data flow of the loop that identifies the toe offs The loop runs as long as the current sample number i is lower than the total number of samples a As long as h the current heel strike number is higher than d the total number of heel strikes one will be added to the value of i and eventually the loop will end If h is lower than d it will be examined if i is higher than or equal to the point of the current heel strike 21 HS h 21 Is i lower than HS h 21 one is added to i and the loop is repeated If i is higher than or equal to HS h 21 it is examined if i is lower than the successive heel strike 21 HS2 h 21 If i is higher than or equal to HS2 h 21 the toe off should have been identified in the current stride thus one is added to i to jump to the next sample and one is added to h to advance the search field to the following stride If
36. walk so that pathologic walk can be detected This is called artificial intelligence Bibliography 1 2 S 4 5 6 7 8 9 10 11 12 13 14 15 16 Interview with Hanne Mette Ochsner Ridder 21 2 2008 summary enclosed Jan Stavnshgj Engineer assistant Andersen Annette Lolk Kjeld Demens i danmark i det n ste arti Ugeskrift for l ger 2004 Encyclop dia Britannica Dementia http search eb com eb article 9029876 2008 Simmons C Ross Ethier Craig A Introductory Biomechanics From Cells to Organ isms Cambridge University Press first edition Frendved Charlotte ldre overlever nar narkoseleegen gar stuegang Nyt p Hvidovre Hospital 2006 Jantzen Christian Motiveret indstilling af musikterapi til forskningsradet for kultur og kommunikations pris til et dynamisk forskningsmilj 2007 http www kommunikation aau dk nyheder musikterapi Musikterapi_Dynamisk2007_010207 pdf 2007 Lemaire et al Christophe Surface micromachined sensors for vehicle navigation sys tems http www analog com en content 0 2886 997 255F 255F8077 00 html 2008 Aldridge David Music Therapy in Dementia Care Jessica Kingsley 2000 United States of America Department of Defense Global positioning system standard positioning service performance standard http gps afspc af mil gpsoc documents GPS_Signal_Spec pdf 2001 Analog Devices Ultracompact 2g
37. would like to direct special thanks to music therapist Hanne Mette Ochsner Ridder for participating in the interview Reader instructions The project has been structured by a problem based method that consist of three parts e Problem Analysis e Problem Solving e Summary In the end of the report appendices are represented The appendices are composed by the group and contain further explanations about selected topics A CD is attached to the report and contains the complete code for the micro controllers and the report in pdf format Sources are structured by the Vancouver method where 1 refers to 1 in the bibliography When the source reference is referred before a period the source reference only refers to the concerned sentence If the source reference is after a period the source reference refers to the section Figures equations and tables are consecutively enumerated in every chapter with captions and source references The following abbreviations will be used throughout the report e uC Meaning micro controller e AP Meaning Access Point e ED Meaning End Device Mike Thagaard Hagelskjaer Ann Sofie Holm Henriksen Carina Jensen Lasse Sohrt Petersen Steffen Vangsgaard Contents 1 Introduction I Problem Analysis 2 Method for Problem Analysis 3 Dementia 3 1 Dementia in General 2 2 Ho nn 3 2 Frontotemporal Dementia 2 2 2 2 aa 4 Music Therapy 4 1 Music Therapy in General 2
38. 2004 3 Frontotemporal dementia is the fourth most frequent cause of de mentia and patients suffering from this make up for 5 10 of the dementias 26 Patients suffering from frontotemporal dementia often get a personality disturbance Some patients tend to get overactive which means they wander Wandering is per se not unhealthy for the patients but if the patients wander at night instead of sleeping it becomes a problem Wandering can be a sign of the patient s state of mind Perhaps the patients are aggressive and restless and therefore wander instead of sleeping 1 To calm down the patients medicine is administered which can cause them to fall To avoid medicating the patients music therapy has been used as a calming method The music therapist often sings known songs to the patients and structures the session which means that the music therapist sings a song in the beginning and the same song in the end of a session After a few sessions the patients become familiar with the situation Even though the patients might not remember it they can recognise the situation and the patients become more relaxed for every session 1 Through the problem analysis it has become possible to answer the initiating problem The experiment conducted by music therapist Hanne Mette Ochsner Ridder shows that music therapy has a calming effect on patients suffering from frontotemporal dementia A music therapy session is quite expensive and time dema
39. 650 bo E 500 650 Samples Samples c d Figure C 9 The different filters that were tested C 6 Pilot Experiment 6 Radio Activity Effect on Voltage Reference Objective The objective of this experiment was to determine the effect of current consumption during CC2500 radio activity on the voltage level of the power supply Furthermore it was desired to determine the data transmission time of the ED Materials e Oscilloscope e The analogue circuit e The ED e The AP e PC Procedure The procedure was performed two times The first time the target board and the uC were supplied with power from the enclosed battery holder with 2 AAA batteries and the second time from 3 AAA batteries To determine when the ED transmits data to AP port P4 3 was toggled immediately before and after the function SMPL_ SUCCES SMPL_ SEND C 6 Pilot Experiment 6 Radio Activity Effect on Voltage Reference 121 ED was started and the pushbuttonmode_ 3 where the transmission was continuous was activated Vcc and port P4 3 was connected to an oscilloscope Results The results of the experiment can be seen in figures C 10 and C 11 The time consumed between point 1 and 2 was the time between the wC was brought out of low power mode 1 to the function SMPL_ SUCCES SMPL_ Send was initialised The time between point 2 and 3 is the time where the radio was listening whether another device was transmitting to AP At this point the radio was only r
40. 70 pA Standby Mode 0 7 yA Off Mode RAM Retention 0 1 yA e CC2500 2 4 GHz radio frequency transceiver CC2500 current consumption in transmit mode with 0dBm output power 21 2 mA 25 26 Chapter 8 Specifications A Figure 8 1 An overview of the hardware of the system Power Supply Three 1 5 V batteries will be used as power supply which shall supply the analogue part of the system and the uC To ensure that the supply voltage of the uC would not raise over the max voltage of 3 6 V 22 a regulator is being used e Regulator input gt 3 V e Regulator output 3 V e Battery output gt 3 V Battery life is calculated from 8 2 Software Specifications 27 battery capacity in Ah Total current through the system u 3600 10 3 Ah 0 5 10 3A 750 10 6 A 270 10 64 21 2 10 3 A From these specifications it is possible to design implement and test every part of the x 159h analogue system 8 2 Software Specifications This section will provide the specifications of requirements of the software in the project The requirements have been divided into two groups user requirements and other requirements The user requirements have been illustrated by use case diagrams 8 2 1 User Requirements These are requirements set by the user of the system In this case the care taker or the music therapist In this section there will be a description of the functional requi
41. B 1 S55 100 37 7 OdB ao 100 21 2 46 1 1dB sae x100 18 1 259 When the front of the radio is pointed towards the AP it is the 1 dB amplification which loses fewest packages and the 12 dB amplification loses most packages Then the average value is calculated when the back of the radio is pointed towards the AP 39 38 12dB x1 15 44 d a 00 5 44 50 15 B 1 19 Od 255 100 9 67 33 39 1dB x100 13 08 259 C 4 Pilot Experiment 4 Package Loss over Distance 117 When the back of the radio is pointed towards the AP the 1 dB amplification loses fewest packages and the 0 dB amplification loses most packages Discussion When the front of the radio is pointed toward the AP the ED can connect to the AP at a longer distance than when the back of the radio is pointed towards the AP In theory this should be the opposite because when the antenna is pointing toward the AP it should give the best connection at a longer distance The amplification of the radio is important because the stronger it is the fewer packages is lost between the radio and the AP Conclusion On the basis of this experiment it is chosen to use the amplification 1 dB because the range between the AP and ED is longer than at 12 dB and the loss of data is less than at both 12 dB and 0 dB in both experiments Except from a single out layer the result from the 1 dB amplifications had the least loss
42. C where the data was recorded for off line analysis using the GUI 4 The data was analysed using the developed Matlab script 5 The real gait events phases and parameters were identified in the signal visually and compared to the events phases and parameters that was identified by the data analysis The results can be seen in the following subsections 11 2 Results Normal Walking at Low Velocity In this test the subject was asked to walk with a low velocity The subject walked the distance of 13 meters in 24 71 seconds hence walking with an average velocity of 0 53 m s or 1 9 km h The results of the test can be seen in table 11 1 Event Visually True Deviation False Percentage Registered Registered Registered False of True Heel Strikes 14 14 0 0 0 Toe Offs 13 13 0 0 0 Strides 13 13 0 Table 11 1 Low Velocity The first column shows the type of gait event or parameter The second column shows the number of visually identified gait events the true number The third column shows the number of gait events registered correctly by the system The fourth column shows the deviation between the second and the third column The fifth column shows the total number of the different events registered by the system that is the number of correct identifications plus the number of incorrect identifications The sixth column shows the number of gait events registered by the system which did not take place The s
43. CSCTL2 SELM_1 4 BCSCTL2 amp SELS 5 BCSCTL2 DIVS_1 Line 1 the basic clock system control 1 BCSCTL1 is set to run with 8 MHz Line 2 the internal digitally controlled oscillator control register DCOCTL is set to run with 8 MHz Line 3 the main clock is selected as DCOCLK at 8 MHz The usage of a bitwise OR ensures the register to get the value 1 Line 4 the sub main clock source is selected to be DCOCLK The bitwise AND ensures the main clock to remain as DCOCLK Line 5 the sub main clock is divided by two to produce a frequency of 4 MHz This is done to set TACCRO as high as possible to obtain a more precise frequency Configuration of I O Ports On the uC there are four available digital I O ports each having eight I O pins To control these ports each of them must be configured Unused pins are configured as output pins to prevent a floating input and reduce power consumption 1 P1DIR BIT2 2 P1REN BIT2 3 P10UT BIT2 4 P1IE BIT2 5 P1IES BIT2 6 P1IFG amp BIT2 7 P2DIR BITO BIT6 BIT7 8 P2REN BITO 9 P20UT BITO 10 P3DIR OxFF 11 P30UT 0x00 50 Chapter 9 Design and Implementation 12 P4DIR 13 P40UT OxFF 0x00 Line 1 sets P1 2 General purpose digital I O pin as input This corresponds to the push button The rest is set as output P1 0 and P1 1 are equal to the LEDs Line 2 Enables pullup pulldown resistor on P1 2 Line 3
44. Chapter 10 Test of the System The data processing function of the GUI is also tested When the Data Analysis button is pressed the heel strikes toe offs cadence and the swing stance ratios are calculated From the test it is concluded that the GUI functions correctly since the different functions are performed successfully Chapter 1 1 Test of the Entire System In this chapter the entire system was tested The purpose of the test was to determine the ability of the system to identify the different gait events and phases To do this a number of tests were performed The tests are described in the following sections 11 1 Method 1 The system was placed lateral on the ankle of a healthy subject see figure 11 1 Figure 11 1 Shows how the system is placed on the subject in the tests 2 The subject was instructed to walk a certain distance in one of the following ways e Normal walking at low velocity e Normal walking at normal velocity e Normal walking at high velocity e Walking with knee lifts e Walking on the front of the feet 83 84 Chapter 11 Test of the Entire System e Walking lateral e Walking backwards The distance covered and the time consumed was registered to calculate the velocity The distance covered was measured to be 13 meters The time consumption was derived from the number of samples recorded in the different tests 3 Data were transmitted live to the AP that were connected to the P
45. Examination MMSE or the Clock Drawing Test which are being used to assess the mental status of the patients 29 The MMSE consists of 11 questions regarding five areas of cognitive dysfunctions orientation registration attention and calculation recall and language The test takes about 10 minutes and the maximum score is 30 points If the patient has a score of 23 or below it is a indication of cognitive dysfunction The other test The Clock Drawing Test is also used to quickly test for cognitive dysfunctions The patient is asked to draw the face of a clock and put in the numbers 1 12 Afterwards the patient is asked to add the arms so that the time for instance is 11 10 The Clock Drawing Test indicates if the patients may have a cognitive dysfunction The Clock Drawing Test is often used in combination with the MMSE 38 Even though these tests are being used dementia cannot be diagnosed on the basis of them alone 24 25 1 Physiologically a widespread loss of nerve cells associated with the shrinkage of brain tis sue is associated with dementia 4 Many diseases can trigger this but often the reason is unknown 37 The most common reasons are e Alzheimer s is the main reason It causes neurons in parts of the brain to slowly die e Multi infarct Dementia is caused by a large number of emboli in the brain that prevent the supply of oxygen to the brain cells 36 e Parkinson s Disease e Alcoholism The widespread
46. Principles of Biomechanics amp Motion Analysis Lippincott Williams amp Wilkins first edition Rubak et al Jens M Klarringsrapport for Identifikation og udredning af demens og demenslignede tilstande i almen praksis Dansk selskab for almen medicin 2001 Rubak et al Jens M Klinisk vejledning Demens i almen praksis Dansk selskab for almen medicin 2006 Stokholm Jette Frontaldemens en handbog melin e olsen rb http www ugeskriftet dk portal page portal LAEGERDK UGESKRIFT_FOR_LAEGER TIDLIGERE_NUMRE 2006 UFL_EKCMA_2006_42 UFL_EKCMA_2006_42_50195 2006 Webster John G Medical Intrumentation Application and Design John Wiley amp Sons Inc third edition 1998 ISBN 0 471 15368 0 Robinson et al L Effectiveness and acceptability of non pharmacological interventions to reduce wandering in dementia a systematic review International Journal of Geri atric Psychiatry 2006 Wallace Lenore Kurlowicz Meredith The mini mental state examination mmse The Hartford Institute for Geriatric Nursing 1999 Karpantschof Line Margrete Normann Miriam Hvad er musikterapi http musikterapi eu page_id 45 Biometrics Ltd Goniometers and torsiometers http www biometricsltd com y 20gonio htm 2008 Everett Marion Trew Tony Human Movement an Introductory Text Churchill Liv ingstone fourth edition 2007 Hansen et al Mette Tandrup Musikterapi http www cancer dk Alt om kraeft behandling alternativ behan
47. Readfromflash Vocstabilisationtime see sec sec radioef fect SMPL_ SUCCESS 3 6ms 178us 74 4us 15 75 0 5ms 4 37ms It is seen that the total execution time of the functions is less than the time period between each sample 14 2 ms Flash Memory used by Code By using IRA Embedded Workbench IDE it is possible to determine the amount of flash memory used by the code The memory map of the ED showed that there is used 7 8 kB of memory The memory map of the AP showed that there is 6 6 kB memory These two amounts could however be reduced since there is still comments to the code included sPeerFrameSem To test the execution time of sPeerFrameSem aphore in the AP port P4 3 is toggled while the semaphore is set to one To perform this test port P4 3 must first be set as an output port P4DIR BIT3 The time consumed in the semaphore is obtained on an oscilloscope and can be seen in figure 10 7 This execution time is less than the time period between each sample which ensures that no stack overflow will occur ADC In order to test the ADC resolution known DC voltages were sent into the ADC The DC voltages varied from 0 V to 3 5 V To verify the input voltages a multimeter was used The code was adjusted so the ADC could be tested separately i e no digital filter was included The test was performed by connecting ED to the COM port and using the debugger mode in IAR Embedded Workbench The results could there
48. SR_register LPM1_bits msg 0 Flash_ptr b if SMPL_SUCCESS SMPL_Send linkID1 msg sizeof msg BSP_TOGGLE_LED2 while b 0 __bis_SR_register LPM1_bits BSP_TOGGLE_LED1 BSP_TOGGLE_LED2 56 Chapter 9 Design and Implementation Before entering the while loop the variable Flash_ptr is set to point at the address OxAA10 which is the same address as when beginning to write to flash memory msg 0 will at this point contain the values from the A D conversion just performed msg 0 Flash_ptr will overwrite msg 0 with the value from the initial flash address 1 which is OxAA11 This procedure is repeated 10 times not shown in the code copying 10 samples into the array of msg When the 10 samples are copied the value b is decremented and msg is transmitted to the AP the same way as in pushbuttonmode 3 see section 9 3 When b reaches zero the program will enter the while loop where the uC enters low power mode 1 and flashes both LEDs The program will be in this state until power is reset and the uC will execute the main function from the top By letting b count down from where it is set in pushbuttonmode 5 section 9 3 no data will be read from the flash memory where no data have been written to Digital Filter It is chosen to use a digital filter to remove noise that may occur after the anti aliasing filter and to further specify the signal Filter Design As stated in
49. Systems Acceleration board schematic http www mikroe com pdf accel_board_schematic pdf Tekscan Flexiforce user manual http www tekscan com pdfs FlexiforceUserManual pdf 2005 Appendix A Interview Guide Interview with Music Therapist Hanne Mette Ochsner Ridder The initial problem of the project is that music therapy for a long time has been used as a part of the treatment in patients suffering from dementia At Aalborg University music therapists have been researching this kind of music therapy and it has been observed that the therapy helps the patients suffering from dementia to relax and defeat their tendency to wander The music therapists desire a technology which makes it possible to document the effect of music therapy with more quantitative measurements Our object with this project is to develop and implement a system for wireless monitoring of the activity level in people with severe dementia This is the occasion for us wanting to meet you to get a discussion about the subject Our supervisor has told us that you have been doing some research in exactly music therapy directed at dementia affected people We are hoping that a meeting with you can give us a better understanding of the issue and wish to discuss the following e Briefly about what music therapy is in generel e Music therapy applied on people suffering from dementia Which kind of dementia What is their characteristics How does a sequence o
50. a day and will thereby not be able to monitor the patients at all time Therefore quantitative tests are needed The collected data of the questionnaires revealed a fall in the restless behavior but the questionnaires had inadequate data and could therefore not be used in statistics None of these tests are suitable for the Cochrane database because of the need of quantitative data The effects of music therapy are to increase life quality and provide peace and quiet for the patient It is desirable to show that the patient is becoming more relaxed This is a subjective decision and cannot be measured A system to measure unrelaxed walk could be a solution The question is when is it a negative way of walking around It could indicate that the patient have higher life quality if the patient is more relaxed but it does not tell the whole truth An idea could be to monitor the circadian rhythm or the walk rate of the patients For instance it would be positive if the patient is walking in the morning and the afternoon and is calm during the evening and night There has to be made some definitions on positive and negative behavior Constant wandering must be assumed to be negative Sometimes the patients tend to be so exhausted by wandering that they fall asleep right after they sit down They can also be very restless and do not have the peace to be sitting down for a while Some patients get a bed guard to avoid them from falling out of the bed because
51. aa 2 at zero g see figure 9 2 11 The ADXL311 is capable of measuring both positive and negative accelerations to at least 2 g The accelerometer is capable of measuring static acceleration forces such as gravity allowing it to be used as a tilt sensor The quiescent supply current is typically 0 4 mA 11 37 38 Chapter 9 Design and Implementation Micro Acce Common Figure 9 1 Diagram of the power supply The 4 5 V of the batteries are regulated through the 3 V regulator and distributed to the C and the evaluations board accelerometer via a double dip switch PIN 8 XouT 1 326 V Your 1 500 V PINS XouT 1 500 V Yout 1 674 V m PIN 8 Xout 1 500 V Your 1 326 V m XourT 1 500 V Yout 1 500 V PIN 8 Xout 1 674 V Your 1 500 V EARTH S SURFACE Figure 9 2 The figure shows the theoretical output response according to the orientation of the accelerometer at rest 11 9 1 2 Accelerometer 39 Le Vop Karr ERST Yon 2 NC NC 151 a L3 t COM NC NOCONNECT 2 ADXL311 BOTTOM VIEW Figure 9 3 Pin configuration of the ADXL311 11 The pin configuration of the ADXL311 is shown in figure 9 3 and the pin function description is given in table 9 1 Pin No Mnemonic Description 1 ST Self Test 2 4 5 NC Do Not Connect 3 COM Common 6 Yori Y Channel Output T Xout X Channel Output 8 Vpp 2 4 V to 5 25 V Table 9 1 Pin function description
52. activity level of patients suffering from frontotem poral dementia who tends to wander was developed The system is a prototype and this chapter is about further developing of the system There are both advantage and disadvantages at the developed system With the system it is possible to measure the activity level of patients suffering from frontotemporal dementia It will then be possible to measure how much music therapy influence the patients It is also possible to detect the swing and stance phases of the gait There are several aspects which have to be optimised before the system can be used in a clinic setup Optimised system In the current system the accelerometer the batteries and the ED are placed on a veroboard This has to be attached to the ankle which is done by taping the system to the ankle There has to be a more permanent solution so it is possible to sleep with the system and walk around without altering the orientation of the axis on the accelerometer The current system is equipped with only one accelerometer and only using one axis which means that it is not possible to make a full gait analysis If a full gait analysis is wanted the system has to be expanded with more accelerometers for instance on both ankles It will then be possible to detect more gait events for example midstance acceleration midswing and deceleration If the system is expanded it could be used to detect pathological walk and not only measuri
53. alise the data Furthermore it will be possible manual to compare data 9 2 3 Graphical User Interface in Matlab 47 collected before and after sessions of music therapy In figure 9 11 an overview of the func tions in Matlab is given Receive Data i x a Save Load Vata ps dla Figure 9 11 The processes in Matlab Matlab recieves data from the AP and it is being visualised right away It is then possible to go to different modules The user can choose to save or load data or to analyse the data When the data have been saved it is also possible to compare data from a previous data collection Receive Data This module receives data from the AP Save Load Data This module allows the user to save or load data Analyse Data This module identifies events of heel strike and toe off These parameters are being used to calculate the ratio of swing stance phase Furthermore the cadence is being calculated Compare Data This module allows the user to compare data received before and after sessions of music therapy Visualise Data This module visualises the results of the received data 48 Chapter 9 Design and Implementation 9 3 Design and Implementation of Functions on End Device In the following section the design of the most important functions in ED and AP will be described These sections are based on 21 and 22 For each function there will be a short explanatio
54. ality can differ from person to person Some people exhibit apathy while others become overactive 13 In this project the focus will be on the last group These patients tend to hide their jewelery and other personal belongings because they want to be sure of not loosing it but they forget that they did it Some of the patients do not like to let the staff bath them or help them to the toilet so the staff let the patients do it on their own 1 The patients can also suffer from depression or present minor mood alterations The memory and the sense of direction are either influenced late in the process or not at all Frontotempo ral dementia starts slowly and the symptoms are gradually deteriorating until death occurs The average course of the syndrome spans around ten years from the first symptoms to 3 2 Frontotemporal Dementia 9 death 13 There has not been found a cure for frontotemporal dementia but the patients receive medicine to be calmed down 15 Music therapy is an alternative to medicine and it is also used to calm down the patients 1 Chapter 4 Music Therapy 4 1 Music Therapy in General Music therapy is a method that uses musical interaction in order to help people with mental or physical illness and to enhance quality of life 14 In certain cases music therapy can support some treatments by e g strengthening the immune system by dissipating tension It has been proved that the therapy has positive effects o
55. ameSem aphore is decremented 9 5 Data Analysis In the following section the analysis of the acceleration signal will be explained Matlab receives the filtered acceleration signal from the AP and the data analysis is then executed in Matlab The objectives of the analysis are e to identify the points of heel strike e to count the number of strides e to identify the points of toe off e to calculate cadence e to calculate swing stance ratios The acceleration signal and the different gait events and phases can be seen in figure 9 17 9 5 Data Analysis 63 actual heel strike detected toe off TOFF actual toe off HS2 detected heel strike HS stance phase StP swing phase SwP i stride ST Figure 9 17 The figure shows the x axis acceleration signal of a complete gait cycle one stride The actual and detectable gait events the calculated gait phases and the threshold values that are used in the data analysis are marked Identifying Heel Strike and Counting Strides In appendix C 5 the heel strike has been identified in the acceleration signal The heel strike is visually detectable as a bend in the curve succeeded by a negative peak see figure 9 17 Using simple algorithms in Matlab it is easier to detect the peak than the bend Identifying the heel strike as the peak instead of the bend will only provide a marginal delay to the detected heel strike compared to the actual heel strike 1 2
56. an at 0 dB amplification Figure C 6 shows what percentage of the packages is lost when the ED is sending data to the AP from different distances The percentage of lost packages varies for the 0 dB 12 dB and 1 dB amplification In the figure C 7 the same three graphs can be seen This time the experiment has been made with the back of the radio pointed toward the AP Again the 12 dB amplification lost the ability to connect to the AP first this time at a distance of 7 meters At 0 dB and 1 dB amplification the ED this time connected and sent up to 25 meter from the AP 116 Appendix C Pilot Experiments Loss of Data back En T T T T 0B H dB 12 dB Loss of Data in 5 T 15 Distance in Meter Figure C 7 Results from the second experiment where it again can be seen that the amplification at 1 dB loses less packages To see which amplification is the best the average values for the 12 dB 0 dB and 1 dB amplification are calculated This is done by adding the package loss at the different distances dividing by the number of packages 255 that were sent By doing this the average package loss for every amplification was found Afterwards the result is divided with the number of packages and multiplied by 100 so that the result is in percent First the average value is calculated when the front of the radio is pointed towards the AP 96 17 12d
57. and saved into a new array tmp When the entire array is full the variable counter will be equal to 10 and the if statement will be entered In this loop the entire array tmp is copied into the array msg place by place When the 10 sample is copied counter is reset and the uC enters low power mode 1 Port 1 Interrupt Service Routine When there is an input on P1 2 i e the button has been pushed down the port 1 interrupt service routine will be called The following code shows the procedure for the interrupt service routine __interrupt void Port_1 void volatile long 1 pushbottonmodet for 1 0x186A0 1 gt 0 1 P1IFG amp BIT2 __bic_SR_register_on_exit LPM1_bits When the push button has been pushed the pushbuttonmode will proceed to the next mode After this a delay will ensure the pushbuttonmode only to be added by one while the in terrupt activates on a falling edge and therefore could register more than one input After the delay 250 ms the interrupt flag is cleared for a new interrupt to set Timer A Interrupt Service Routine The timer AO interrupt service routine is called every time the timer A control has counted to TACCRO 57143 which corresponds to 70 Hz The following code shows the timer AO interrupt service routine procedure __interrupt void Timer_A void ADC10CTLO ADC10SC 60 Chapter 9 Design and Implementation This starts sample and conversion Thus sample an
58. and thereby produce unreliable data 10 7 5 Electromyography Electromyography EMG is a measure of muscle action potentials The method can be performed both invasive and non invasive The invasive method uses needle electrodes that are inserted directly into the muscle The output signal has an amplitude off 0 1 5 mV 27 This procedure may be connected with pain and the inserting point may become inflamed if used over a longer period The non invasive technique called surface electromyography sEMG uses skin surface electrodes to measure action potentials in the muscle The surface electrode can be placed on specific leg muscles used while walking e g Gastrocnemius me dialis Tibialis anterior or Rectus femoris By measuring the action potentials it is possible to register each time a step is taken There is however some drawbacks when using surface electrodes the amplitude of the measured signals is smaller than when measured directly in the muscle This means that the need for signal amplification is greater than in invasive measurements In addition artifacts from e g skin impedance other action potentials and electrical interference have to be removed before analysing the signal 27 7 6 Accelerometer An accelerometer is an electromechanical device that measures acceleration forces There are two types of these forces static like the constant force of gravity and dynamic caused by moving or vibrating an object By sensi
59. ange Objective The objective of this pilot experiment was to determine the range of reach from the AP to the ED Materials e ED e AP e Computer e Measuring tape Procedure In IAR Embedded Workbench the eZ430 RF2500 Sensor Monitor Demo v1 02 was turned on and the AP was connected to the ED Initially the ED was placed right next to the AP to observe the signal strength Afterwards the ED was moved slowly away from the AP to observe how far away it could be from the AP without losing connection Results When the ED was placed right next to the AP the signal strength was 73 When moved out to maximum distance the strength fell down to 33 The distance reached before the connection was lost was 26 5 m Figure C 4 Distance from AP to ED Discussion The experiment was not made through walls It is expected that the distance would be shorter if it was tested in this manner This could be tested the same way if found usable A way to minimise the loss of packages is to include a handshake system between ED and AP This means that each package is given an ID which is incremented for each package When AP receives a package it controls that the ID number is one higher then the last If this is not the case e g if the number is two higher than the last received AP will send a message to ED instructing it to resend the missing package This will however not be a problem in this project since all data are saved in flash memo
60. appendix C 5 a digital low pass filter is chosen An IIR filter is chosen for this application since it has a shorter execution time and since the order of the filter becomes smaller than when using a FIR filter The equation of the filter that is being implemented is as follows y n boz n bein 1 azy n 1 Where y n is the output y n 1 is the previous output bo b and a are the filter coefficients x n is the input and x n 1 the previous input The flow of the signal in the first order IIR filter can be seen in figure 9 13 bo 2 x n y n x n 1 y n 1 Figure 9 13 Signal flow graph of the first order IIR filter The code is being implemented in ED and since the uC has only 32 kB memory the code has to be as compact as possible The filter coefficients were found by using the functions showed below Fs 70 n 1 Wn 0 5714 c a butter n Wn c 0 5563 0 5563 9 3 Design and Implementation of Functions on End Device 57 a 1 0000 0 1126 where n is the order of the filter Wn is the 3 dB frequency in rad which are calculated from 20 Fs 2 A and c are the filter coefficients which are used to design the filter in C Phase response of Digital 1th Order Butterworth Filter Phase degrees 100 i i i fi i i 0 5 10 15 20 25 30 35 Frequency Hz Figure 9 14 The figure shows a linear phase response which means that all frequencies experience the same time delay
61. arity bit an address bit address bit mode and one or two stop bits see figure E 7 The UCMSB bit controls the direction of the transfer and selects LSB or MSB first where LSB Appendix E MSP430f2274RHA 133 first is typically required for UART communication The period of the bit is defined from the chosen clock source and the configuration of the baud rate registers Mark sT ER E E 2nd Stop Bit UCSPB 1 Parity Bit UCPEN 1 Address Bit UCMODEx 10 Optional Bit Condition 8th Data Bit UC7BIT 0 Figure E 7 The character format of the UART 22 The UART has two interrupt vectors one for transmitting and one for receiving data For transmitting data an interrupt flag is set by the transmitter which indicates that the char acters can be transfered to the transmit buffer For receiving data the interrupt flag is set each time a character is received and loaded into the receive buffer 22 Interrupts The following subsection describes the interrupts of the uC The nearer a module is to the CPU the higher the priority which means that if two interrupts are requested at the same time the interrupt with the highest priority is taken There are three types of interrupts e System reset e Non maskable NMI e Maskable The Non maskable NMI interrupts can not be masked by any general interrupt enable bits and can only be generated by three sources which is if a fault in an oscillator occurs if
62. ble for the user to change the threshold in the GUI Physical Dimensions and Weight As described in the problem analysis patients who suffer from frontotemporal dementia tends to hide or destroy jewelry and similar objects so the system has to be discreet and should not bother the patient because otherwise they will remove it The current system is small but still not that small that it is unnoticed The system also has to be fastened with tape so it does not move when the patient is walking Because of screws which the accelerometer is fasten with it is a bit painful to wear the accelerometer so in fact the patient would be likely to notice it quickly Chapter 1 3 Conclusion In this project a system to measure the activity level is developed In this chapter it will be concluded whether the system fulfil the specifications This chapter will focus on the results of the entire test Patients suffering from frontotemporal dementia often get a personality disturbance starts wandering may behave different and often their ability to speak is affected Some patients become overactive and tend to wander restless around To calm the patients down the patients are being medicated but another method would be more appropriate for instance music therapy Music therapy is being used to calm the patients down without medication but it is difficult to prove that music therapy has an effect on the patients This has lead to the following
63. celeration and thus the output voltage of the fixed accelerometer should be zero The recorded signals does not reveal any visible difference in noise density or amplitude between the different signals Conclusion Neither of the signals revealed any noise of significant magnitude Furthermore no difference in noise between the signals that was disturbed by movement and the signals which wires were at rest Therefore it can be concluded that the signal is not affected by mechanical noise induced by movement of the signal carrying wires giving that the recorded experimental data in the following pilot experiments are valid 114 Appendix C Pilot Experiments Mechanical Noise X axis Wires at Rest x axis Wires under Movement Voltage v 0 50 100 150 200 250 300 350 400 450 500 Voltage v 0 580 100 150 200 250 300 350 400 450 500 Samples Figure C 5 The upper figure shows the signals from the X axis with and without distur bance of the wires The lower figure shows the signals from the Y axis with and without disturbance of the wires C 4 Pilot Experiment 4 Package Loss over Distance Objective The objective of this experiment was to test how much data the CC2500 radio loses and test which amplification is to be used in the CC2500 radio Materials e uC e Matlab e Measuring tape e Computer Procedure A subject was holding the ED at different distances from the AP On the ED the antenna was placed on the
64. column shows the total number of the different events registered by the system that is the number of correct identifications plus the number of incorrect identifications The sixth column shows the number of gait events registered by the system which did not take place The seventh column shows the percentage of incorrect identifications compared to correct identifications Precisely 34 strides were definitely performed by the subject They were counted by the subject and by observers Part III Summary 89 Chapter 1 2 Discussion In the problem analysis it was described that patients who suffer from frontotemporal de mentia tend to wander restless around The problem statement of the project is how it is possible to measure the activity level of the patients This system was developed to provide a mean to test if music therapy had an effect on the patients using the wandering behaviour as an indicator In the following sections it is discussed whether the system complies with the problem statement Overall Functionality The system can calculate the number of strides taken by patients and also calculate the swing stance ratio In the problem analysis it was described that the patients tends to wander restless around It is not a problem that the patients walk around but it becomes a problem if they do it at night or have a restless or apathetic gait The current system cannot differentiate between these types of gait Therefo
65. components of the evaluation board are placed on both sides of the board To offer an overview of the placement of the components figure 9 8 has been created CDC2 100nF J 8 t O 2170901 OJO Figure 9 8 Component sketch of the evaluation board The left half of the figure represents the top view of the evalutaion board with the pins 1 through 4 placed to the right In the right half of the figure the board has been flipped over thus representing the bottom view of the evaluation board with the pins placed to the left The two red lines represent the two connections which intersects the evaluation board 44 9 2 Software Design 43 9 2 Software Design According to the use cases in section 8 2 the system has been split up in different processes In the following section the different processes in the ED the AP and in Matlab will be described These process designs have been made based on the software requirement speci fication In the first subsection the process design on the ED will be described the next subsection deals with the AP and the third subsection is about the GUI 9 2 1 End Device The main objective of the ED is to receive data filter the received data save it to flash memory and transmit it to the AP when sampling period is done In the following an overview of the other function
66. d conversion is done with a frequency of 70 Hz 9 4 Design and Implementations of Functions on Access Point Basic Configuration of Microcontroller The MCU _Init function perform necessary initialisations for the AP The following code shows how the function is called and the basic clock and DCO Digitally Controlled Oscillator are set to run at 8 MHz This is done the same way as on the ED BCSCTL1 CALBC1_8MHZ DCOCTL CALDCO_8MHZ In the following code the USCI clock source is selected to be the sub main clock SMCLK that runs with 8 MHz After this the USCI_ AO baud rate control register is set to 9600 Baud Then the USCI_ AO control register is set to run with sub main clock by setting UCSWRST Then interrupts are enabled on USCI_ AO RX UCAOCTL1 UCSSEL_2 UCAOBRO 0x41 UCAOBR1 0x3 UCAOMCTL UCBRS_2 UCAOCTL1 amp UCSWRST IE2 UCAORXIE __enable_interrupt Initialise Network After the uC and the radio on the AP have been initialised the network is initialised by calling the following function SMPL_Init sCB BSP_TURN_ON_LED1 The sCB parameter semaphore callback is a function pointer to a callback function which is executed when a message has been received by the AP The Red LED is toggled to indicate the network have been correct initialised The following code shows the sCB callback function static uint8_t sCB linkID_t lid 9 4 Design and Implementations of Functions on Acces
67. d out while the circuit was supplied by the batteries and several measurements where carried out with declining input voltages from 5 00 V to 1 58 V with a power supply The results can be seen in table 10 1 Regulator Input Regulator Output 5 00 V 3 00 V 4 50 V 3 00 V 4 00 V 3 00 V 3 50 V 3 00 V 3 30 V 3 00 V 3 20 V 3 00 V 3 10 V 3 00 V 3 00 V 2 97 V 2 40 V 2 13 V 2 03 V 1 81 V 1 65 V 1 47 V 1 58 V 0 10 V Table 10 1 Regulator output response means that this is the measurement which was supplied with the batteries 71 72 Chapter 10 Test of the System It can be concluded that the voltage regulator successfully regulates the battery supplied voltage from a voltage of up to 4 50 V to a voltage of 3 00 V which is satisfactory to meet the requirements of the accelerometer It is also seen that if the battery voltage declines to 3 00 V or below the output of the regulator is affected From 3 00 V to 1 65 V the output of the regulator is on average 0 23 V lower than the input max 0 27 V min 0 18 V In at least some of this range the wC will still be able to function but the signal from the accelerometer will be invalid When the input voltage declines to 1 58 V or below the output voltage is approximately zero and will not be sufficient to supply the uC Test of the Output Response of the Accelerometer The output response of the accelerometer was tested by probing the X output and the Y output of the eval
68. dling behandlingsformer musikterapi 2007 Martine Michael Simpliciti for simple low power small rf networks http jartiuch wordpress com 2007 09 25 simpliciti for simple low power small rf networks 2007 101 35 36 37 38 39 40 41 42 43 44 45 IT og Telestyrelsen Goniometers and torsiometers http www it borger dk sikkerhed mobiltelefoner og straling radiobolger og mobilstraling 2006 Davidsen Ole Multi infarct dementia http www netdoctor co uk diseases facts multiinfarctdementia htm 2005 Davidsen Ole Demens http www netdoktor dk sygdomme fakta demens htm 2007 Braunberger Peter The clock drawing test http www neurosurvival ca ClinicalAssistant scales clock_drawing_test htm 2001 Johannesen Peter Frontotemporal demens http www demensnet dk universe1 dementiaforms frontotemporal Medline Plus Dementia http www nlm nih gov medlineplus dementia html 2008 American Cancer Society Music therapy http www cancer org docroot ETO content ETO_5_3X_Music_Therapy asp 2007 Smith Stanley Wolf Richard F M Student Reference Manual for Electronic Instru mentation Laboratories Pearson Prentice Hall second edition 2004 Mark Susanne Ardahl Edith Kemisk fiksering er en uansteendig behandling http www kristeligt dagblad dk artikel 83350 Debat Kemisk fiksering er en uanstaendig behandling 2005 MikroElektronika Development
69. e connected with the uC and therefore have to be taken into consideration while configuring the I O ports of the uC see figure E 8 The CC2500 is a low cost low power transceiver which has a software configurable frequency band 2400 2483 5 MHz The data rate can be configured from 1 2 to 500 kBaud with a programmable output power from 20 to 1 dBm The CC2500 supports amplitude frequency and phase shift modulation formats e Amplitude shift keying ASK e On off keying OOK e Frequency shift keying FSK e Binary FSK 2 FSK e Gaussian frequency GFSK e Minimum frequency shift keying MSK 119 RADIO CONTROL DEMODULATOR GDOO ATEST GDO2 x w gt lt w a 14 uu o w u PACKET HANDLER DIGITAL INTERFACE TO MCU MODULATOR RBIAS XOSC_Q1 XOSC_Q2 Figure E 8 The simplified block diagram of the CC2500 transceiver 19 Appendix E MSP430f2274RHA 135 SimpliciTI The radio of the uC uses a wireless network protocol called SimpliciTI SimpliciTT is e low cost e low power e simple e flexible e low data rate and low duty cycle e ease of use Wireless technology can use radio waves instead of cable to carry data from one point to another The data is modified from an electric signal to electric waves sent and then modified back to an electric signal when received 35 The technology was designed so that it would be easy to implement and deploy The protocol reduces power consum
70. e detected The figure contains the signal and two straight lines which represent the preset threshold values It is seen that the signal never intersects tresholdHS and that it has no general resemblance with the normal gait signal 88 Chapter 11 Test of the Entire System Stride Counter In addition to the other tests the stride counter was tested To test the stride counter the subject was instructed to take a certain number of strides at normal gait and moderate velocity The test was performed as the tests described above only the subject was asked to perform 34 steps rather than walk 13 meters The 34 strides were counted by the subject and by observers of the experiment To verify the stride counter the registered steps were compared to the known number of steps that were taken The data from this test was also used to verify the identification of heel strike and toe off see table 11 4 Event Visually True Deviation False Percentage Registered Registered Registered False of True Heel Strikes 35 35 0 0 0 Toe Offs 34 29 14 7 5 17 24 Strides 34 34 0 Table 11 4 Stride Counter The first column shows the type of gait event or parameter The second column shows the number of visually identified gait events the true number The third column shows the number of gait events registered correctly by the system The fourth column shows the deviation between the second and the third column The fifth
71. e patient not to walk around as much as earlier and partly due to medicin partly to a very quick progression of her illness Pick s Disease the patient tends to fall and has developed an unhealthy posture The patient group is often highly medicated to calm them down This high intake of medicine may result in more patients falling causing broken bones including teethes Another method could be physical restrainment of the patient but this is not allowed These are some of the main reasons why it is important to find a way to calm down the patients without pacifying them If the medicine is not dosed very precisely it can pacify the patients which is another problem It would be positive to keep the patients calm in a natural way without medicine During music therapy the calming element in the voice is used instead of medicine When the songs are being chosen there has been a conversation with the relatives to find out what kind of music the patient enjoys and would be able to recognise Often the effect of the song is larger if the patient knows the song but even unknown songs might be effective as the voice has a calming effect itself when the therapist sings The therapist sings what is going to happen instead of saying it because the patient finds it easier to relate to a song A session always begins with the same song and ends with the same song During a session the therapist sings for the patient for about 20 30 minutes Patients with
72. e selectable as LFXTICLK VLOCLK or DCO CLK and selectable for individual peripheral modules All of the clock signals can be divided by 1 2 4 or 8 to obtain the wanted frequency 21 22 132 Appendix E MSP430f2274RHA Input Output Ports The uC has four 8 bit I O ports P1 P2 P3 and P4 Each of these 32 bits can be individually programed to produce any combination of input output and interrupts Furthermore each I O has an individual pullup pulldown resistor and independent I O data registers It is however not possible to use all port and their bits as inputs because the eZ430 RF2500T target board only has 18 pinouts see figure E 6 Three bits are however dedicated to the two LEDs red and green and a push button for manual interrupts The red LED is located at P1 0 and the green at P1 1 The push button is located at P1 2 21 22 Of these 18 pins pins 13 18 are dedicated to test the connection between the wC and the 2 4 GHz radio frequency transceiver Pin 1 and 2 are ground reference and supply voltage respectively These pins are by default set to ground and Vcc and do not need setup Battery Board N fi Over a eZ430 RF2500T Oman Target Board N f eo Om PS mi ICANTADE UDA TRIMS 1 3 TOBA 9 000000000 000000000 jJ 18 available development pins Figure E 6 eZ430 RF2500T target board with 18 pinouts 20 From the accelerometer one signal is obtained Since the accelerome
73. eceiving information The time between point 3 and 4 is the time where the data was transmitted and SMPL_ SUCCES SMPL_ Send ends The voltage drop of Vcc were measured to 34 mV with two AAA batteries and 25 mV with three AAA batteries The profile of Vcc where the target board and uC were powered from three AAA batteries contain some oscillations of the spike between reception and transmission and after transmission ends The oscillations after transmission end effects Voc after SMPL_ SUCCES SMPL_Send was completed The time was approximately 0 5 ms A A Petty Petey om Figure C 10 The result from the test using 2 AAA batteries The upped signal is Voc and the lower is port P4 3 while toggled The total time consumed is 3 68 ms Discussion The data transmission time was shown to be approximately 3 7 ms The payload of these transmissions was 10 bytes per transmission This is by default the maximum but this is possible to alter by changing the settings of the radio An increase of the payload will increase the time of each transmission or the execution time of the function SMPL_ SUCCES SMPL_ Send The main time of the transmission period is when the radio is listening whether another device is transmitting to AP If it was known that only one ED was able to connect to each AP this time consumption could be reduced The time of the actual transmission can be 122 Appendix C Pilot Experiments Ho EM N AX 3 660
74. ensors which are able to measure the level of activity When selecting the sensor to use in this project several parameters stated in chapter 6 have to be considered These parameters are e Placement e Cost e Size e Analogue signal processing e Possibility for gait analysis These parameters together with the different sensors have been placed in table 7 1 The sensors have been given a score from one to three for each parameter in order to determine how well the specific sensor would do in this project e 1 was given if the sensor would perform with zero or few complications or disadvantages in relation to the parameter e 2 was given if the sensor would perform with some or moderate complications or disadvantages in relation to the parameter e 3 was given if the sensor would perform with several or severe complications or disad vantages in relation to the parameter 7 7 Selecting a Method of Measurement Sensor Place Costs Size Analogue Possibility for ment Signal Processing Gait Analysis Pedometri 2 1 2 1 3 Goniometer 1 3 2 2 1 FSR 1 1 1 2 2 GPS 1 2 1 1 3 EMG 3 1 2 3 2 Accelerometer 1 1 1 2 1 Table 7 1 The table shows the results of the evaluation of the different methods From the considerations in table 7 1 it is concluded that the sensor which will be used is the accelerometer An accelerometer can be placed anywhere on the body surface with different outpu
75. est of the Software 75 Test of Sampling Frequency Each time an interrupt from timer A interrupt service routine is received the sampling and conversion of the ADC is started see section 9 3 To test the sampling frequency 70 Hz the frequency of timer A interrupt is tested The test is performed by toggling an output port each time an interrupt is received by the timer A interrupt service routine Port P4 3 is used to show the frequency since this is already an output port The following code is used to toggle the port P40UT BITS P40UT amp BIT3 Figure 10 2 shows that the result from the test of the sampling frequency is 70 4 Hz PE 1 AX 70 423Hz AYC1 0 00V _ Figure 10 2 The figure shows the time between each toggle of port P4 3 The time is 14 2 ms which is equal to a sampling frequency of 70 4 Hz Execution Time of SMPL_SUCCESS SMPL_Send To test the execution time of the function SMPL_SUCCESS SMPL_Send in the ED port P4 3 is toggled while sending data to AP This is done the same way as explained in the previous test The time consumed is 3 6 ms and is obtained on an oscilloscope see figure 10 3 Execution Time of Save to Flash Memory To test the execution time of save to flash memory in the ED the port P4 3 is set while saving to the flash memory The time consumed is obtained on an oscilloscope and can be seen in figure 10 4 Execution Time of Filter To test the execution time of
76. eventh column shows the percentage of incorrect identifications compared to correct identifications Normal Walking at Moderate Velocity In this test the subject was asked to walk with a moderate velocity The subject walked the distance of 13 meters in 14 seconds hence walking with an average velocity of 0 93 m s or 3 3 km h The results of the test can be seen in table 11 2 11 2 Results 85 Event Visually True Deviation False Percentage Registered Registered Registered False of True Heel Strikes 12 10 16 7 1 10 Toe Offs 8 1 87 5 1 100 Strides 11 10 9 1 Table 11 2 Moderate Velocity The first column shows the type of gait event or pa rameter The second column shows the number of visually identified gait events the true number The third column shows the number of gait events registered correctly by the system The fourth column shows the deviation between the second and the third column The fifth column shows the total number of the different events registered by the system that is the number of correct identifications plus the number of incorrect identifications The sixth column shows the number of gait events registered by the system which did not take place The seventh column shows the percentage of incorrect identifications compared to correct identifications Normal Walking at High Velocity In this test the subject was asked to walk with a low velocity The subject walked the dis
77. f therapy proceed Etc e The effect of music therapy How does the therapy affect the people suffering from dementia How does the therapy affect the wandering and night sleep How does the therapy affect the generel activity and stress level of the dementia affected people Etc Based on the meeting we are hoping to identify and specify the requirements to a technology which can be used for the issue 103 Appendix B Interview Summary of Interview Interview with Hanne Mette Ochsner Ridder music therapist at Institute for Communication at Aalborg University Hanne Mette Ochsner Ridder has worked with patients who suffer from frontotemporal de mentia which is the group who tends to get restless and aggressive This behavior can be measured by observations and questionnaires but this demands that the staff is there to measure which is difficult At the moment there is a group from Architecture and Design who has been working with a project where they were trying to measure how much people are walking in parks in the city with help from GPS This is an obvious method to use on patients with dementia and they now try if this might be used indoor by placing several sensors in each room of the nursing home or care center Such kind of monitoring may however cause ethical problems Some patients with Alzheimer s disease can also develop tendency to wander but this is typically not the case Some leaves the home for long wa
78. fore be read in the flash memory section When using the debugger mode the ED is powered by the COM port resulting in a measured reference of 3 69 V The results can be seen in table 10 2 10 2 Test of the Software 79 13 64Hz Figure 10 7 The figure shows the execution time of the sPeerFrameSemlaphore It can be seen that the time consumed is 8 8 ms Input Expected 10 bit After 2 Expected hexa Measured hexa Deviation 0 0 V 0 0 0 0 0 0 5 V 138 34 22 23 29 1 0 V 277 69 45 47 2 9 1 5 V 415 103 67 6A 2 9 2 0 V 554 138 8A 90 4 3 2 5 V 693 173 AD B4 4 0 3 0 V 831 207 CF DA 5 3 3 5 V 970 242 F2 F6 1 7 Table 10 2 The table shows the input voltages to the ADC the value expected with a 10 bit ADC the value after right bit shift by two the expected hexa value and in the last column the measured valued From table 10 2 it can be seen that the measured value is very close to the expected value The deviation from the expected values can be caused by the right bit shift by two which leads to a loss of data It is however more likely that the deviation is caused by the input voltage which also should be taken into consideration It is also concluded that recording data and saving in the flash memory are performed successfully since the data in the flash memory are as expected 80 Chapter 10 Test of the System Digital Filter Test To test t
79. fterwards It is at any time possible to use the RESET and EXIT button the system of co ordinates which give the user an overview of which patient the user is working with Afterwards the chosen COM port is opened and the data collection begins The data which Matlab is getting from the uC is plotted in the system of co ordinates In this process it is important that the uC is connected to the computer and that a connection between the AP and ED is established otherwise Matlab will get a timeout after 10 seconds if no data is received A timeout will result in a fatal error in Matlab which means that Matlab have to be rebooted and the uC has to be reset This means that the ED must be reset because AP creates a new network which must be joined and thereby loosing potential recorded data If the check box Autoscale Y is check marked Matlab automatically adjusts the axes Close COM port When the data collection is over the function Close COM port should be used The connec tion between the computer and the uC is then disconnected After the COM port is closed it is possible to slide through all the data which have been collected by using the slider beneath the system of co ordinates It is also possible to slide in the vertical direction if the signal fill more than the plot window Save Data After the COM port is closed it is possible to save the data The name of the file is gener ated to be the civil registration number of the patient
80. g give an operating frequency of 40000004 z a 363 6kHz 9 2 which is within the desired range Line 2 defines the variable Flash ptr to char 0xAA10 The data type char defines the size of the data to be save each time a sample is saved in flash A char contains 8 bits which is equal to the output of the ADC after compressing the result see section 9 3 OxAA10 and the pointer points to the address where the first sample is written Line 3 initialises the Flash Memory Control Register 3 FCTL3 By setting FWKEY the rest of the register is set to 0 This includes LOCK which when it is unlocked makes it possible to write to flash Push button Mode 1 Join Network The variable pushbuttonmode is defined as a char with the value zero during the initialization After the basic configuration of the uC the program enters low power mode 1 LPMI in the following code while pushbuttonmode 1 __bis_SR_register LPM1_bits While the ED is waiting for new interrupt from the push button it is in LPM1 to minimise the consumption of current The operation mode LPM1 is chosen since the SMCLK is still active When an interrupt from the push button is received pushbuttonmode increments and the program leaves the while loop Afterwards the timer A is initialised and ED keeps on trying to join the network which is created by the AP By the following while loop the network is attempted to joined while SMPL_NO_JOIN SMPL_I
81. ge output sensitivity matches the values from the data sheet which is 1 74 mV g 15 74 Chapter 10 Test of the System 10 2 Test of the Software In this section the software will be tested The tests have been split into two parts 1 test of the uCs and 2 test of the GUI In the following there will be an overview of the tested parts followed by an explanation of each test The following parts are tested e In the uC it is tested whether the sampling frequency Fs is 70 Hz whether the ADC performs as expected whether the system is able to transmit data live whether data recording and data saving in flash memory are performed success fully whether the data stored in the flash memory is identical to the data saved by Matlab after being sent whether the digital filter fulfils the specifications whether the codes to the wCs are smaller than 32 kB whether it is possible to get a stack overflow This is done by testing the execution time of the following functions x Filter Save to Flash Memory x SMPL_ SUCCESS SMPL_ Send Read from Flash Memory x sPeerFrameSem e Regarding the GUI the following functions are tested Create connection to AP and read data Save data Load data Visualise data Continually Saved data x Results regarding processed data The Micro Controllers This subsection describes how the tests regarding the uC are performed and presents the results 10 2 T
82. he filter the filter code was implemented in AP which was plugged in the USB of the computer Signals with various frequencies from 1 Hz to 35 Hz and a fixed magnitude of 100 was sent through the wC from Matlab The peak to peak output magnitude was measured from each frequency When all the frequencies were tested the bode magnitude plot of the filter was plotted see figure 10 8 In figure 10 8 it can be seen that the cutoff frequency is approximately 20 Hz where the signal is attenuated 3 3 dB Magnitude response of Digital 1th Order Butterworth Filter 1 9 0 0 0 0 gt gt 9 6 T theoretical bode plot practical bode plot H dB Hz Figure 10 8 The figure shows the result from the test the red dots and the theoretical bode magnitude plot the blue line The practical bode plot matches the theoretical bode plot 10 2 Test of the Software 81 Test of Graphical User Interface There are several functions to test in the GUI It is tested if the PC has established connection to the AP and thereby showing data If the GUI is receiving data in the system of co ordinates when the START button is used the connection between the PC and the AP is established This also tests if the GUI visualises the data correctly This is shown in figure 10 9 coma w Enter Name test2steffen Enter civil registration number test2steffen35 al T T j T T 7 1 T START
83. he following instruction These steps are called the fetch decode execute cycle Analog to Digital Converter In the uC a 10 bit Analog to Digital Converter ADC10 is implemented The ADC10 module is integrated with the reference and data transfer catalogue DTC The DTC can prevent CPU intervention so the ADC10 samples can be converted and stored in ADC10 Memory ADC10MEM The method which is used to convert analog signals into digital form is successive approximation This method is very fast and has a high resolution The Appendix E MSP430f2274RHA 129 ADC10 tests if the signal is in the upper or the lower half of the spectrum 0 1023 If the signal is over 512 the first bit will be set to 1 otherwise it will be set to 0 on the place for the most significant bit The interval in which the signal is within is split in half and the signal is again tested in the upper and lower interval Since it is a 10 bit ADC it performs 10 estimates and makes the closest possible approximation to the voltage of the signal see figure E 3 42 This is just an approximation and it will be more accurate the more bits the ADC has The digital output Napc when using straight binary format can be calculated from equation E 1 22 Vin Vpr Napc 1023 Va Vi Vr and Vp are the upper and lower limits of the conversion and V is the input voltage When Vin gt Vr the Napc is 1023 and zero when Vin lt Vr 22 E 1
84. he foot is in contact with the floor or swinging forward to prepare for the next step respectively In walking there is always a period of time at which both feet are in contact with the floor simultaneously this period is called double stance see figure D 2 5 RIGHT LEFT LEFT RIGHT RIGHT LEFT INITIAL PRE SWING INITIAL PRE SWING INITIAL PRE SWING CONTACT CONTACT CONTACT Time percent of cycle l l f Double le p si Double support R Single support Al L Single support gt I f 1 10 15 45 apa 100 R Stance er A Swing phase I e Swing phase mage are Stance phase gt O 40 55 85 100 I l E 1 I Double upp Figure D 2 Terminology and timing of the gait cycle 32 The Stance Phase At an average gait velocity the stance phase accounts for about 60 of the gait cycle At lower velocities the stance phase may constitute more than 70 of the gait cycle Also the period of double stance increases with decreased velocity When walking very slowly the double stance period may last as long as 46 of the gait cycle In very fast gait the double stance period can be reduced to 14 of the gait cycle Appendix D Gait 125 The following stages are present during the stance phase The stages can be seen on figure D 2 e Heel Strike When walking normally the initial contact between the foot and the floor consists of the leading limb striking the floor with the heel
85. he given system Thus the actors are outside the system but interacts with the system In the diagrams the actors will be notated as in figure 8 2 Actor 2 Figure 8 2 Notation of an actor in the use case diagrams The use cases will be notated by ovals see figure 8 3 If a function is included in several use cases this will be notated by an arrow from the use case including the function to the other use case which is being included This is illustrated in figure 8 3 Actor Use Caset ee fe Figure 8 3 Use case diagrams notated by ovals Use case 1 includes use case 2 8 2 3 End Device Receive Data Receive data from the accelerometer Scenario 1 Collect data from accelerometer 8 2 3 End Device 29 Patient Accelerometer MSP430 Access Point includes Figure 8 4 The use case diagram for the ED Exceptions The accelerometer is removed or damaged The battery is empty Filter Data Receives data from the accelerometer and filter the data Scenario 1 Receive data from accelerometer include Receive data 2 Filter data Exceptions The accelerometer is removed or damaged The battery is empty Save Data to Flash Memory Data received from the accelerometer will be saved in flash memory and transmitted to AP when all data have been collected Scenario 1 Receive data includes Filter Data 2 Save the data in flash memory Exceptions No data
86. hout medicine This is where music therapy can be useful During a music therapy session the calming element in the voice is used instead of medicine 1 9 The songs are being chosen together with the relatives but even unknown songs might be effective as the voice itself has a calming effect when the therapist sings 1 In a music therapy session the therapist sings what is going to happen instead of saying it because the patient finds it easier to relate to a song A session always begins with the a song and ends with the same song During a session the therapist sings for the patient for 11 12 Chapter 4 Music Therapy about 20 30 minutes Patients with dementia recognise the songs and the music therapist which sooths the patient The patient sometimes starts the session with restless wandering but often will the patient sit down next to the therapist and sometimes even fall asleep It is different from patient to patient how many sessions of music therapy they need to get the soothing effect Patients with severe dementia receive sessions on a daily basis but for patients suffering from a milder form of dementia one session a week will be sufficient 1 To show the effects of music therapy music therapist Hanne Mette Ochsner Ridder mu sic therapist with area of specialisation in dementia has measured the heart rate of six patients 1 In the study heart rate was measured at the same time every day one week prior to receiving mu
87. i is lower than HS2 h 25 it is examined if the value of the current sample xout is higher than a preset threshold value thresholdTOFF If xout is lower than or equal to thresholdTOFF the next sample is examined by counting i up by one If xout is higher than thresholdTOFF p is assigned the value of i 1 Now it is examined if xout is higher than the value of the successive sample q 1 p If xout is lower than or equal to q 1 p the next sample is examined by counting i up by one If xout is higher than q 1 p the point of the toe off is registered by assigning the value TOFF h with the value of i and 3 is added to i 66 Chapter 9 Design and Implementation Calculating Cadence The common way to determine and express the cadence of gait is to count the number of steps performed per minute thus expressing the cadence in strides min This method however will only give an updated expression of the cadence every minute A way to get a more frequent estimate of the cadence is to divide 60 seconds with the duration of every given stride in seconds thus revealing an expression of the cadence for every single stride To determine the duration of a particular stride ST n the point of heel strike is subtracted from the point of the successive heel strike ST n HS2 n HS n In this case the duration of the stride is given in samples Therefore the cadence of particular stride in strides per minute Cadence n is found by dividi
88. ing phase the swinging limb moves in front of the stance limb in order for forward movement to take place To swing succesfully the limb must be shortened to ensure clearence between the foot and the floor This is achieved by flexion of the hip and knee joint and dorsi flexion of the ankle To conserve energy the swinging limb is not lifted further from the ground than necessary In normal gait the average clearance in mid swing phase is around 2 cm The following three stages is present during the swing phase The stages can be seen on figure D 2 e Acceleration The force generated by the hip flexors and the plantar flexors acceler ates the swinging limb forwards e Mid swing Mid swing happens simultaneous with mid stance e Deceleration Towards the end of the swing the lower limb muscles actively work to decelerate the limb preparing it for heel strike The muscle activity in the deceleration requires less energy than in acceleration 32 126 Appendix D Gait Other Temporal Components e Cadence When considering abnormal gait it is important to have knowledge about the step rate The term cadence is used to indicate the number of steps per minute The cadance is mainly dependent of the velocity of walking At low velocity a cadence of 40 50 steps per minute is normal As velocity increases so does cadence at moderate velocity the cadence is about 110 steps per minute and this number increases until running occurs If a patient has jo
89. int stiffnes pain muscle weaknes or poor balance a decrease in cadence is expected 32 23 Spatial Components e Stride Length is the distance between two consecutive foot floor contacts e Step Length is the distance between the feet when both are in contact with the floor Stride and step length depend on multiple factors such as the length of the lower limb the age of the subject and the velocity of walking Short lower limbs high age and low velocity reduces the step and stride length 5 32 Gait Changes with Age The changes in gait that occur between old and young people are easy to detect Even though gait itself varies among people a change in the pattern can be seen With age the velocity decreases together with the stride length and cadence which is reduced in older people In young people the length of strides were in 1969 found to be 89 of their height and this length was reduced down to 79 in people over 80 years The angle of the foot and the width in stride was found increased in older people which is held together with their reduction in balance ability Usually there is a loss in spinal rotation and arm swing which contribute to reduction in velocity and cause a reduction in step length and sometimes in the cadence Factor Effect of Ageing Step length Decreases Stride length Decreases Stride width Increases Cadence Little change or a decrease Single stance period Decreases Double stance period Increases
90. ions by setting a time interval if the time interval is expired the watchdog will reboot the system The watchdog timer can however also be used to other purposes if the watchdog function is not needed The watchdog timer can be programmed to create interrupts in given time intervals the same way as timer A and B In this project the watchdog timer is not used and is therefore stopped Basic Clock Module In the uC the basic clock module is designed to meet the requirements of low system costs and low power consumption By using three internal clock signals it is possible to find the best balance between system performance and power consumption The basic clock module consists of the following three clock sources e LFXTICLK is a low frequency high frequency oscillator e DCOCLK is an internal digitally controlled oscillator DCO which is a fast turn on clock and stabilices in less than 1 us e VLOCLK is an internal very low power low frequency oscillator From the clock sources the following three clocks signals are available e Auxiliary clock ACLK sourced from a 32768 Hz watch crystal a high frequency crystal or from the internal very low power low frequency oscillator ACLK is software selectable as LFXT1CLK or VLOCLK and selectable for individual peripheral modules Main master clock MCLK is software selectable as LFXT1ICLK VLOCLK or DCO CLK and is the system clock used by the CPU e Sub main clock SMCLK is softwar
91. is subtracted from the output response of the X axis at gravity 1 g This yields the sensitivity to positive acceleration on the X axis 11 62V 1 44V 0 18V 10 1 The output response of the X axis at 0 g is subtracted from the output response of the X axis at minus gravity 1 g This yields the sensitivity to negative acceleration on the X axis 1 27V 1 44V 0 17V 10 2 The average output response on the X axis is calculated 0 17V 0 18V 2 0 175V 10 3 Equivalent calculations are carried out for the Y axis Positive acceleration on the Y axis 1 68V 1 50V 0 18V 10 4 10 1 Test of the Hardware 73 PIN 8 Xout 1 27V Y out 1 50V PIN 8 XouT 71 62 V Y 1 50V Xout 1 44V OUT Y out 150V EARTH S SURFACE Figure 10 1 The figure shows the measured output response according to the orientation of the accelerometer at rest 11 Negative acceleration on the Y axis 1 33V 1 50V 0 17V 10 5 Average output response on the Y axis ae 0 175V 10 6 It can be concluded that the output response corresponding to 0 g is 1 44 V on the X axis and 1 50 V on the Y axis In addition the average output sensitivity has been determined to be 175 mV g on both axes As mentioned in 9 1 the normal range for the output corresponding to 0 g is 1 5 V on both axis This does not match the measured output response of the X axis In this application however this is acceptable The the avera
92. k 4 km per hour placed at the ankle Voltage V Time sec Figure C 2 A result from the 1 7 g accelerometer is shown It shows that the signal is saturated at about four volts at four km per hour placed on the ankle C 1 Pilot Experiment 1 Accelerometer Saturation Test 111 6 km per hour placed at the ankle Voltage V Time sec Figure C 3 A results from one of the tests with the 2 0 g accelerometer is shown It shows that the signal is not saturated at six km per hour and placed on the ankle Discussion The output voltage could still attain a level where it would saturate if a person stomps When using the 2 0 g accelerometer the axis can be orientated in all three ways since it did not saturate in any of the tests made Further analyses about this is necessary to make a decision Conclusion By analysing the results from all the tests it was found that the signal from the 2 0 g accelerometer was not saturated not even when raising the velocity up to six km per hour Though the signal was not saturated at six km per hour this is not a guarantee that a patient cannot make a move that will cause the output to saturate but still this accelerometer is found operable in this project The selection of orientation will be made in a later section 112 Appendix C Pilot Experiments C 2 Pilot Experiment 2 End Device Max R
93. le to measure these changes but especially with this group of patients there are certain complications connected to some of these methods By analysing the possibilities and limitations of the considered methods of measurement it should be possible to decide which method would be suitable for this purpose The following methods will be discussed in this chapter e Pedometer e Goniometer e Force Sensing Resistor e Global Positioning System e Electromyography e Accelerometer 7 1 Pedometer A pedometer is a small device that registers and counts number of steps This however can be difficult to place on the patient without the patient either noticing removing and in worse case hiding or breaking it Furthermore the pedometer is not the most exact way to measure the activity level since it counts the total number of steps in a given period of time It is not possible to determine when each step is performed This data does not contain enough information about the gait to describe the effects of music therapy Walking itself is not harmful to the patient and therefore knowing only the total number of steps is not useful in this case 1 To increase accuracy the pedometer has to be placed at the hip which is in the immediate range of reach of the patient As stated in chapter 3 patients suffering from frontotemporal dementia sometimes wander around at night 1 This would be difficult to register with a pedometer since it is not possible
94. lks Music therapy is not meant to make the patients walk less if they have a need of walk ing around That is why it is difficult to decide when the walking can be classified as unwanted It is difficult to get quantitative tests because it demands estimations The walking frequency has to be reduced to a healthy level which has to be defined in a sub jective manner A way to test whether the person is suffering from dementia is by asking the patient to e g do the clock test by drawing a watch Some patients with dementia may draw all the numbers in one corner and therefore not cope with the task It is not possible to give a diagnosis from these tests alone Another test is called the Mini Mental State Examination which is used by general practitioner Hanne Mette Ochsner Ridder showed a video from a session of music therapy The pa tient in the video suffers from frontotemporal dementia and does not have any language which often is seen in these types of patients The only word she uses is bingo which she uses with a different tone of voice to express herself The patient in the video lives in a 105 106 Appendix B Interview special care center in which it is possible to walk around in the corridors There is a garden in the center and corridors around this where she can walk The walks may happen at night time but the patient in the video primarily walks around at day time The patient receives medicine which causes th
95. memory and 1KB RAM In figure E 2 the blockdiagram of the wC is shown Each block will be described in the 127 128 Appendix E MSP430f2274RHA P1x P2 x P3 x P4 x ADC10 Ports P1 P2 10 Bit Ports P3 P4 2x8 1 0 12 Interrupt 2x8 I O Channels capability fpull up dow Autoscan pull up downi resistors resistors Basic Clock System MCLK 28P AO JTAG Brownout WOT IrDA SPI Interface fe Protection 3CC USCI BO SPI T2C Watchdog Timer_A3 15 16 Bit Registers Spy Bi Wire annnnnunnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn ST NMI Figure E 2 The block diagram of the MSP430F2274RHA following subsections Central Processing Unit The uC contains a central processing unit CPU which is the brain of the computer The architecture of the uC combined with its five low power modes is optimised to achieve extended battery life in portable measurement applications The CPU consists of a control unit registers 1 16 and the ALU Arithmetic Logic Unit The CPU executes programs which are stored in the main memory The CPU executes the instructions one after another by the following steps e Fetch the next instruction from memory into the instruction register e Change the program counter to point to the following instruction e Determine the type of instruction just fetched e If the instruction uses a word in memory determine where it is e Execute the instruction e Start over to begin executing t
96. meter and an evaluation board The different parts of the analogue circuit will be explained in the following sections 9 1 1 Power Supply The power supply supplies the evaluation board including the accelerometer and the uC The power supply consist of three batteries a voltage regulator and a dual dip switch The batteries are regular AAA batteries The AAA batteries are alkaline batteries with a nominal voltage of 1 5 V giving a total voltage of 4 5 V The rated capacity of a battery is 1200 mAh giving a total of 2600 mAh The voltage regulator is of type LE30CZ from ST Microelectronics It has a typical output voltage of 3 V The voltage from the battery is regulated and then lead to a double dip switch which enables the user to turn on or off the power of the evaluation board that includes the accelerometer and the uC individually A diagram of the power supply can be seen in figure 9 1 9 1 2 Accelerometer The accelerometer that is used in this project is the AD XL311 The ADXL311 is a dual axis acceleration measurement system on a single monolithic integrated circuit Dual axis means that the accelerometer is capable of measuring acceleration in two directions simul taneously The two output signals are analogue voltages proportional to acceleration in the two directions X and Y At the typical input voltage Via 3V the sensistivity at X and Y is 174mV g with a tolerance of 15 and at all input voltages the output is nominally V
97. ms 1 AX 273 22Hz AYC2 Mode a Source x Y JO Y1 gt Bere Yan Figure C 11 The result from the test using 3 AAA batteries The upped signal is Vcc and the lower is port P4 3 while toggled The total time consumed is 3 66 ms reduced or extended by adjusting the baud rate As default the baud rate is set to 250 kbit s but it can be adjusted within the range of 10k to 500k bit s A side effect of reducing the baud rate is that the radio will be active over a longer period of time which will increase the current consumption When ED is powered by three AAA batteries it was shown that there are some oscillations on Voc These oscillations persist to after the function SMPL_SUCCES SMPL_ Send ends This has to be taken into consideration when estimating the time of active functions between each sample There should approximately be added 0 5 ms to the execution time of SMPL_SUCCES SMPL_ Send The oscillations in itself is not harmful to the system as long as they do not appear while performing any operations that relay on a steady Vcc e g an AD conversion If Voc drops under a specified voltage the result may by a Power Up Clear PUC which will result in a system reset Therefore may the oscillations be harmful for the system An oscillation may result in a PUC which will lead to a system reset and a loss of all recorded data Conclusion It can be concluded that there should be added 0 5 ms to the execution time of the function SMPL_
98. n Basic Configuration of Microcontroller Configuration of the Analog to Digital Converter When power supply is connected to the uC the basic configuration is automatically initialised since these functions are placed before any interrupts are allowed Therefore no actions have to be taken to setup the uC besides having an AP started A single channel from the accelerometer is A D converted the X axis to be used in the data processing The ADC is configured by the following code 1 ADC1OCTLO ADC1OSHT_3 ADC100N ADC10IE ENC 2 ADC1OCTL1 INCH_O Line 1 In the ADC10 control register 0 the ADC10SHT _3 ADCIOON ADCI0IE and ENC are set ADC10SHT _3 controls the sample and hold time which in this case is 64 x ADC10CLKs The commands ADC10ON and ADCIOIE turn on the ADC10 and enable interrupts from the ADC10 The command ENC enables conversions This must be set to 1 before any conversion can take place In the ADC10 control register 0 the reference to the ADC is selected with the command SREF _x The reference is by default set to Vr Veco and Vr Vss and will therefore not be changed Line 2 In the ADC10 control register 1 INCH _0 is selected While the ADC is running in single channel mode INCH _x selects the channel to be converted In this case INCH _0 is equal to channel AO or pin3 on the evaluation board The command ADC10SC start conversion is placed in ADCIOCTLO in timer_A inter rupt service routine see section 9 3
99. n quality of life and also on patients in connection with operations chemotherapy and in reducing anxiety 33 Music therapists are working with a variety of physical and psychological symptoms The therapists design the music sessions for individuals based on need and music preferences 41 In a music therapy session music can be used both actively and passively Active music therapy includes instruments and passive music therapy includes singing and listening to music Mostly the therapist starts singing and sometimes the patient starts singing along It is not necessary that the patients can play an instruments or sing the important thing is that the patients feel that they are seen and heard during the session Music therapy can take place in group sessions or individual sessions 30 Music therapy is e g used with patients suffering from frontotemporal dementia to calm them down This will be further described in the following section 4 2 Music Therapy and Dementia The patient group suffering from frontotemporal dementia is often highly medicated to calm them down This high intake of medicine may result in patients falling causing broken bones and teeth These are some of the main reasons why it is important to find a way to calm the patients down without pacifying them and without medication Otherwise there can be consequences if the medicine is not dosed very precisely It would be positive to keep the patients calm in a natural way wit
100. n though the system could not find every heel strike when the subject was walking with a moderate velocity the test of the entire system showed that the system functioned It was possible to collect data from the accelerometer to the ED which transmitted the filtered 95 96 Chapter 13 Conclusion data to the AP wireless The AP then transmitted the data to the PC where the data was being visualised in the GUI in the shape of a graph The graph showed the gait events heel strike and toe off clearly It has not been possible to test the system on a patient suffering from frontotemporal de mentia and it is then an assumption that the system could be used by the target group The system requires that the user know what the signal contains so that it is possible to compare data from before during and after a music therapy session The system is simple and easy to use together with the GUI The user only has to place the system on the ankle connect the AP to the computer use the push button at the ED to establish connection to the AP and transmit data and interact with the GUI It is a procedure which do not require any literacy from the user The user only has to type the name and civil registration number in the GUI and then start the transmission From this chapter it is concluded that it is possible to measure the activity level with the developed system Chapter 1 4 Future Perspectives In this project a system for measuring the
101. nclude the DCO and MCLK are set to run at 8 MHz the Baud rate is set to 9600 and interrupts are enabled see appendix C 5 Initialise board and drivers This function initialises the communication between both the wP and the CC2500 radio and the LEDs switches Initialise Network This function initialises the AP as the network hub Listen for a link This function listens for a link request from the ED When this link request is received a successful link has been created sNumCurrentPeers This function increments the number of devices that the AP recognise as part of the network sJoinSem This function decrements sJoinSem for another device to set Define input buffer This function defines a message buffer in which to store the current frame This is done every time the sPeerFrameSem has been set or incremented that is every time the AP receives a frame from the ED Process all waiting frames This function loops through its input queues searching for frames until it has processed all waiting frames Transmit data to PC This function transmits frames to the PC When doing so the green LED will be toggled and the sPeerFrameSem will decrement 9 2 3 Graphical User Interface in Matlab In this subsection the design of the user graphical user interface GUI will be described The GUI has been implemented in Matlab The main objective in Matlab is to receive data from the AP analyse the data save or load data and visu
102. nding and the impact on the patients is not scientifically proved Therefore it is difficult to convince the relatives that music therapy is beneficial for the patients There is a need for quantitative research which can prove that music therapy helps to calm the patients down resulting in less wandering at night This has lead to the following problem statement How is it possible to develop a system which can measure the activity level of patients suffering from frontotemporal dementia who tend to wander 13 14 Chapter 5 Problem Statement Under the problem solving this statement will be attempted to be answered Through the problem analysis some general requirements regarding the system have been specified this will lead to the choice of a measurement method and sensor that will be used in this project Part II Problem Solving Chapter 6 System Requirements In the previous part the initiating problem of the project has been analysed This analysis has made it possible to do an overall requirement specification In the following there will be an analysis of the requirements which will result in some more specific requirements These have been ordered into two groups e Functional requirements e Other requirements The functional requirements are functional demands to the system as output calculations etc while other requirements impose constraints to the design of the system e g place ment size
103. ng 4200 with the duration of the stride 4200 60s 70 Hz Cadence n 4200 St n Calculating Swing Stance Ratio To calculate the swing stance ratio of a particular stride N the duration of the stance phase and the swing phase is determinated using the four values HS n HS2 n TOFF n and ST n see figure 9 17 The duration of the stance phase of the stride StP n is determined by subtracting the point of heel strike from the point of toe off StP n TOFF n HS n 9 3 The duration of the swing phase of the stride SwP n is determined by subtracting the point of toe of from the point of the successive heel strike SwP n HS2 n TOFF n Now the stance and swing ratios Stanceratio n and Swingratio n can be calculated Stanceratio n 100 StP n ST n Swingratio n 100 SwP n ST n If no toe off between to particular heel strikes is registered StP and SwP thus Stanceratio and Swingratio are assigned the value zero As mentioned in section 9 5 and 9 5 heel strike and toe off is registered 1 or 2 samples later than the actual events If this delay is equal in both heel strike and toe off detection it will not have an effect on the swing stance ratio calculation If one of the delays is longer than the other the swing stance ratio will be miscalculated A typical stride has a duration of 90 samples and a stance phase with a duration of 54 samples This gives a swing stance ratio of 40 60 If a heel strike
104. ng bit shifted two to the right after the A D conversion With a power supply voltage reference to the ADC of 3V these values are equal to 1 43 V and 1 48 V since the system is not plane because of bolts to the accelerometer If the system had been plane the values would be equal to 1 5 V This test will thereby indicate if the accelerometer is connected and functions correctly The power supply is indirectly tested If the power supply is lower than 3V the result from the ADC will not be within the stated range since the ADC uses the supply voltage as reference Push button Mode 3 Continual Transmit Data to Access Point When an interrupt is received from the push button pushbuttonmode will now be equal to 3 and enter the following while loop while pushbuttonmode 3 __bis_SR_register LPM1_bits if SMPL_SUCCESS SMPL_Send linkID1 msg sizeof msg BSP_TOGGLE_LED2 54 Chapter 9 Design and Implementation In the loop the program will first make the uC enter low power mode 1 with interrupts enabled The program will leave low power mode when an interrupt is set from the ADC10 interrupt service routine This will happen each time 10 samples have been collected and saved in the variable msg This means that the if statement will be completed at a frequency of 7 Hz Each time the if statement is completed the green LED will be toggled as an indicator of successive transmission Push button Mode 4 Save
105. ng faster and amplitude of each peak corresponding to how aggressively the patient is walking It is not possible to calculate the distance traveled 7 4 Global Positioning System 21 7 4 Global Positioning System Global Positioning System GPS can be used to determine the position of the patient The position is determined by the use of GPS satellites circling in the atmosphere of the earth The accuracy can be affected by different spherical disturbances in general the precision is approximately 15 m varying from model to model By knowing the position of the patient at all time it is possible to calculate the average velocity of the walk The GPS has the advantage that it does not use a specific biomedical signal and can be placed anywhere it is convenient e g under a wrist watch or in ashoe Furthermore it will be possible to locate the patient if he she leaves the nursing home using the GPS A project from Architecture and Design at Aalborg University has examined the possibilities in using GPS for determining the activity level of people walking in parks in the city The project had some problem in determining the indoor wandering due to disturbances from walls and concrete 1 16 Furthermore some other problem may occur namely if the patient is wandering around in a circle and the GPS is unable to register that the patient is moving the wandering will not be registered These deviations will result on inaccurate calculations
106. ng the activity level of the patients The system is now taped to the ankle as described earlier This means that the accelerom eter is not placed at the exact same location every time To provide this it could be an advantage to place it directly on the bone This is though a risky procedure especially for elderly patients This is because it is a very invasive procedure and an operation is always dangerous to elderly people because of the general anaesthesia At elderly weakened pa tients it is a hard load on the body to be operated and afterwards many become seriously ill which can cause death 6 Another permanent method to fixate the system is therefore needed 97 98 Chapter 14 Future Perspectives The accelerometer has a self test function By sending a voltage into the X axis and Y axis pins the output response should be 50 mV corresponding to 0 290 g The uC can be set up to do this before a measurement is started Then the functionality of the accelerometer would be tested on a regular basis 11 At the AP the antenna could be replaced by a better and more expensive antenna The signal strength will be better and therefore the range between the ED and AP would be larger and the loss of data would be reduced The uC contain 32KB 256B Flash Memory and IKB RAM see appendix E It means that the code in the uC has to be as compact as possible If the uC could get more memory it could be possible to make a lot more featu
107. ng the amount of dynamic acceleration it is possible to analyse the way the device is moving 8 Acceleration is defined as the time rate of change of velocity In other words accelera tion is a measure of how fast the speed of an object is changing Acceleration is measured in m s Sometimes acceleration is denoted with a g which is a unit of acceleration equal to Earth s gravity at sea level 18 In analysing human gait measurement of dynamic acceleration could be applied By placing 22 Chapter 7 Methods to Measure Level of Activity an accelerometer on a subject it would be possible to collect a voltage signal corresponding to the acceleration of the subject By applying computer algorithms using e g Matlab this signal could be analysed It would be possible to identify the heel strikes of the subject and thereby count the number of steps performed By placing the accelerometer on the leg of the subject e g on the ankle it would be possible to register any tremors of the leg and possibly identify and differentiate between various types of gait and gait events Furthermore the accelerometers property of measuring static acceleration could be used to measure tilt with respect to gravity Accelerometers are available as relatively small 0 5 mm times 0 5 mm low cost 200 DKR and durable integrated circuits 11 7 7 Selecting a Method of Measurement In the previous section there has been a description of different types of s
108. nit uint8_t linkID_t 0 __bis_SR_register LPM1_bits After the network has been joined the ED keeps trying to link to the AP with the following while loop while SMPL_SUCCESS SMPL_Link amp linkID1 __bis_SR_register LPM1_bits 52 Chapter 9 Design and Implementation Each time the ED sends a frame to the AP a linkID is placed in the beginning of the frame A frame is ten samples which is also called the payload This linkID is send to make the AP recognise whether the frame is a join request or a frame containing data from an already known ED A linkID equal to zero is interpreted as a join request and a linkID larger than zero is interpreted as data frame reception see section 9 4 for further description After the network is joined by the ED and the link to the AP is created the program enters the following while loop while pushbuttonmode 1 __bis_SR_register LPMi_bits As long as pushbuttonmode is equal to 1 the uC is in low power mode 1 The program will wait in this loop until another interrupt from the push button is received Push button Mode 2 End Device Self Test When an interrupt is received from the push button pushbuttonmode will now be equal to 2 The purpose of this mode is to verify that the signal from the accelerometer is operating as intended This will be done by performing a self test While testing the ED must be placed on a horizontal plane surface In figure
109. of the test can be seen in figure C 8 Neither of the signals have been digitally filtered Discussion In figure C 8 only the X axis is shown The reason for this is that it was found that the different gait events where most distinct in the signal from the X axis The heel strike would be easy to identify by detecting the negative peak that occurs one or two samples after the actual heel strike This would only marginally decrease the length of the stance phase The toe off is seen as a positive peak and should be readily detectable In Matlab different digital filters have been implemented Low pass filters with corner frequencies from 10 35 Hz and stop band frequencies from 15 40 Hz has been implemented in different combinations In C 5 Pilot Experiment 5 Gait Event Identification 119 Acceleration and Forces Samples Figure C 8 At point aa heel strike occurs In the acceleration signal the heel strike is seen as a bend in the curve followed by a negative peak a few samples later Toe on and heel off occurs at point b and point c respectively These events are not visible in the acceleration signal At d toe off occurs In the acceleration signal this is seen as a positive peak The stance phase is from a to d and the swing phase is from d to e the following heel strike The phase from a to e is a complete stride addition a high pass filter was implemented to provide pass band filtering Different pass bands in
110. of their restless behavior at night During walks inside the care center the staff cannot follow the patient around because it makes the patient anxious When the patient is outside the perimeter of the care center the staff follows the patient In regular nursing homes there is no possibility to walk around and doors with a coding system are no allowed The feeling of the patients of not being allowed to walk around might make the patient restless or aggressive The patients are able to get far away from their room during their walks By putting GPS sensors in their shoes it is possibly to see the coordinates of the patients This gives the patients a lot more freedom to walk around Music therapy is more widely used in Germany England and Norway than in Denmark This might be because of the duration of the education in Denmark five years Some of the music therapy trainig programmes in other countries is not as long The number of music therapists in Denmark is increasing Appendix C Pilot Experiments C 1 Pilot Experiment 1 Accelerometer Saturation Test Objective The objectives of this experiment were to test if the signal from the 1 7 g accelerometer saturate during normal gait activities and whether it would be necessary to replace it with a 2 0 g accelerometer By testing the signal it should be possible to recognise the frequency and amplitude characteristics of the signal and analyse how the signal changes with changed veloci
111. ometer simply by changing the value of the two capacitors Cz and Cy This filtering improves measurement resolution and prevent aliasing The higher the value the narrower the bandwidth The equation for the corner frequency is 1 Me 271 32k0 C 7 y 42 Chapter 9 Design and Implementation In this project it has been chosen to set the band width to 20 Hz C 5 thus Cz and Cy can be calculated as 1 F Hz __ 022 BRN Oea Ciz y 0 2494 F 1 C and Cy should be 0 2494 F The surface mounted capacitors with the nearest nominal values is a 0 270uF capacitor and a 0 220uF capacitor The 0 220uF capacitor is physically smaller and would be easier to mount in the given slots on the evaluation board therefore this is chosen This gives a corner frequency 22 6 Hz which is satisfactory see equation 9 1 1 F 21 32k0 2204F The function of the three 470 resistors R Ra and Rg are unknown as is the function of the 220kQ resistor Ra which is coupled between the Do Not Connect pin of the accelerometer and ground x 22 6Hz 9 1 The capacitors C and Cs are both 0 1uF capacitors and are applied to decouple the oper ational amplifier and the accelerometer from noise on the power supply The OP284 acts as a unity gain current buffer on the X and the Y signal after the low pass filtration The OP284 is a single supply dual op amp and has a current consumption of 1 35mA at Vag 3V The
112. pecifications Receive Data Receive data from AP Scenario 1 Find the AP 2 Receive data from AP Exceptions Fails to connect to AP or no signal to receive Visualise Data Display saved data or analysed data on a screen through a graphical user interface GUI Scenario 1 Read data 2 Display data Exceptions No data received no data stored Load Patient Data Load information on the patient given by the user via the GUI Scenario 1 Receive patient information 2 Save data Exceptions No data given by the user Save data A record is created where the patient information given from the user the received data analysed data and the results from the comparison Scenario 1 Create the record named after the patients civil registration number include receive patient data 2 Save the data received from AP in the record include receive data 8 3 Accept Test of the Hardware 33 Exceptions No data to save Analyse data The user chooses analysis to be carried out Scenario 1 Create the record named after the patients civil registration number include receive patient data 2 Save the data received from AP in the record include receive data Exceptions No data to analyse 8 3 Accept Test of the Hardware In section 8 1 the hardware specifications are introduced In this section it is explained how these specifications will be tested 8 3 1 Regulator The regulator inpu
113. problem statement of chapter 5 1 How is it possible to develop a system which can measure the activity level of patients suffering from frontotemporal dementia who tend to wander The system basicly contains an accelerometer and a uC The system can detect gait events like heel strike and toe off which indicate that a step has been taken The data analysis part of the system also calculates the swing stance ratio from the heel strike and toe off When testing these functions small complications occurred When the subject walked with moderate and high velocity 3 3 km h and 4 8 km h the data processing sometimes had dif ficulties analysing the data Sometimes a heel strike peak was missing which may be caused by a to low sampling frequency see chapter 12 Also if the subject moved differently than straight forward the data analysis could not detect the gait events because the system was not designed for this type of walk but it was still possible to see that the subject was moving The functionality of the data analysis was optimal when the subject was walking slow with 1 9 km h see chapter 11 In appendix C 5 it is described that gait changes with age for ex ample changes in velocity This means that when elderly people are walking with moderate velocity they walk slower than when the subject was walking with moderate velocity This means that it is possible that the data analysis will find all the gait events in elderly patients Eve
114. ption memory usage lowers system cost and is quick and easy to design with 34
115. pulls up the pin at P1 2 which will ensure that the signal at the port to the push button always is stabil high Line 4 enables interrupts at P1 2 Line 5 sets the PIIFG2 flag with a high to low transition Thus there will be an interrupt on the falling edge Line 6 clears the interrupt flag register IFG for a new interrupt This is done after each push button interrupt see subsection 9 3 Line 7 sets P2 0 P2 6 and P2 7 as input P2 0 corresponds to pin 3 on the eZ430 RF2500T target board P2 6 and P2 7 are used by the CC2500 All other ports are set as output Line 8 enables pullup pulldown resistor on P2 0 Line 9 pulls down the pin at P2 0 which will ensure that there is no signal at pin P2 0 Line 10 sets all P3 pins as output since none of these are used Line 11 sets the output low in the output register thus nothing can be measured at the pins Line 12 sets all P4 pins as output since none of these are used Line 13 sets the output low on the output register Configuration of Flash Memory The flash module of the uC contains 32000 bytes of memory In this memory both code and data have to be stored Therefore it is important to control that the data is not stored in memory adresses where code is located If data from the A D conversions overwrites memory where code is located the results may be a reset of the wC loosing all previous data unpredictable flash writing making it impossible to read flash memory without e
116. ration more than one of the two square wave signals get coupled into the moving plate and the resulting signal at the output of the movable plate is a square wave signal whose amplitude is proportional to the magnitude of the acceleration and whose phase is indicative of the direction of the acceleration 8 The signal is then fed into a buffer amplifier and further into a phase sensitive demodulator which acts as a full wave rectifier The output is a low frequency signal whose amplitude and polarity are proportional to acceleration and direction respectively See the block diagram of the accelerometer in figure 9 6 The two internal 32 kQ resistors have a tolerance of 15 and can be used to set the band width of the accelerometer by adding capacitors 11 This is explained in section 9 1 3 9 1 3 Evaluation Board 41 FUNCTIONAL BLOCK DIAGRAM SELF TEST cbc Figure 9 6 Functional block diagram of the ADXL311 11 9 1 3 Evaluation Board The evaluation board consists of a dual single supply operational amplifier and various resistors and capacitors The accelerometer is also mounted on the evaluation board The diagram of the evaluation board is shown in figure 9 7 1 Vdd 3 vYoOuT ADXL311 2 Xx OUT 4 COMMON Figure 9 7 Diagram of the evaluation board 44 0 220nF SEL HH O 220nF SEL On the evaluation board it is possible to increase or decrease the bandwidth of the ac celer
117. re it has to be optimised to comply with this specific target group If the system should be able to identify unwanted gait there should have been more focus on gait analysis with accelerometers and how the signal behaves Then it could be pos sible to compare the signal with the signal from the literature With the current system the user has to know the normal gait of the patients before it is possible to see if the gait changes Testing and Calibrating Conditions In chapter 11 the system was not only tested during normal walk but also when the subject walked slow fast lateral backwards on the front feet and with knee lifts It was possible for the data analysis function to detect heel strikes and toe offs when the subject was walking slow normal or fast When the subject walked on the front feet it was not possible to detect heel strikes This was expected since no heel strikes occur during this kind of gait Because the data analysis is using heel strikes to find the toe offs it was not possible to detect them either even though they do occur When the subject walked with knee lifts it was possible to detect the heel strikes but not the correct toe offs Thus if patients walk different than normal slow and fast the data analysis becomes unreliable but it is still possible to see if the patients are moving 91 92 Chapter 12 Discussion To calculate the correct swing stance ratio the correct heel strikes and toe offs have
118. rements and a description of other requirements Functional Requirements It should be e calculate swing and stance phase e possible to detect strides taken by the patient and count these e able to perform self test on the system and indicate result to the user Self test should react to low battery false signal from accelerometer false AP ED setup e visualise data Other Requirements The other requirements are e The system should be able to work on the MSP430f2274RHA pC e Matlab should be used for the graphical user interface on the computer e The size of the program has to be as small as possible occupying a maximum of 32 kB 22 e The system should be able to read data from the accelerometer 28 Chapter 8 Specifications e The system should be able to save data on the ED Filter Specification It is chosen to use a digital filter to remove noise The specifications of the digital filter is chosen in C 5 e Cut off frequency is set to 20 Hz e Stopband edge frequency is set to 35 Hz e The sampling frequency is 70 Hz 8 2 2 Use Cases In this section the functional requirements will be illustrated in use case diagrams There will be separate use case diagrams for the ED the AP and the Matlab program The use case diagrams will be followed by an explanation of the functions The diagrams consist of actors and functions performed by the system to the actors The actors interface with t
119. res in the program Also it is a problem to save a lot of data with the current memory With the current system it is possible to save about 5 minutes of data It was a requirement to the system that it should be able to save data up to 24 hours If this requirement is to be fulfilled the memory of the wC should be extended When data are sent from ED to AP and into Matlab the procedure takes just as long as when data is saved in the flash memory Meaning that 24 hours data will take 24 hours to transmit from ED to AP and Matlab Therefore it is important to decrease this time if the system is to be used in a clinic setup The CC2500 operates at a frequency of 2 4 GHz If there are other devices close to the uC which also runs on a frequency of 2 4 GHZ such as microwave ovens mobile telephones or other uCs a collision will happen This means that when the ED needs to transmit data to the AP it listens if there are other devices which communicate with the AP If there are other devices on the line the ED will wait to transmit data until the channel is unoccupied This is called Clear Channel Assessment CCA This means that data will be lost when the ED transmits data if the AP is listening to another device This could be prevented if the AP only is able to connect to one ED The system could be expanded so that the wC can detect things by its own For instance the uC can learn the patients walk and detect if something changes in the patients
120. rest of the register is reset Making it impossible to write to flash All interrupts are now enabled The loop ends with asking if the variable b has been incremented to the value 2100 When b reaches 2100 21000 samples have been written to flash which is the maximum capacity When this event occurs pushbuttonmode 9 3 Design and Implementation of Functions on End Device 55 is incremented and it will not be possible to enter the write to flash mode again If b has not yet reached 2100 the while loop will continue to run for maximum 5 minutes Push button Mode 5 Low Power Waiting mode When an interrupt is received from the push button or the variable b has reached the value 2100 pushbuttonmode will now be equal to 5 The following while loop will therefore run while pushbuttonmode 5 __bis_SR_register LPM1_bits BSP_TOGGLE_LED1 BSP_TOGGLE_LED2 In the loop the program will make the uC enter the low power mode 1 with interrupts enabled Both the green and the red LED are then toggled This state indicates that the entire flash memory has been filled with data from 5 minutes of recording or the user has ended the prior recording Push button Mode 6 Transmit Data Saved in Flash Memory to Access Point When an interrupt is received from the push button pushbuttonmode will now be equal to 6 The following while loop will therefore run Flash_ptr char 0xAA10 while pushbuttonmode 6 __bis_
121. rrors or the uC can even be destroyed so that it can not be reprogrammed When using IAR Embedded Workbench IDE it is possible to create a memory map of the device being programmed This feature allows the programmer to get a clear overview of where in the flash memory data can be saved without any risk of overwriting code This tool showed that it was possible to save data in the range from OxAA10 43536 to OxFC18 64536 In this range it is possible to save 21000 8 bit conversions as hexadecimals When sampling at 70 Hz it makes it possible to save up to 300 seconds of data in the flash memory To save data in the flash memory the flash module has to be initialised This is performed by the following code 1 FCTL2 FWKEY FSSEL_2 FN3 FN1 2 Flash_ptr char OxAA10 3 FCTL3 FWKEY All write and erase operations are controlled by the flash memory timing generator The operating frequency frrcg of the generator must be in the range 257 kHz 476 kHz frre is set in Flash Memory Control Register 2 Line 1 initialises the Flash Memory Control Register 2 FCTL2 In this register a password FWKEY for the register is set This must be set each time a register has to be altered 9 3 Design and Implementation of Functions on End Device 51 In the register the flash controller clock source FSSEL _ 2 is selected to SMCLK which is 4 MHz Furthermore the flash controller clock divider FN3 and FN1 is set to 11 These two settin
122. ry Conclusion The distance the ED can be away from the AP is 26 5 meter under the given circumstances C 3 Pilot Experiment 3 Mechanical Noise 113 C 3 Pilot Experiment 3 Mechanical Noise Objective The objective of this experiment was to test whether the signal from the experimental setup is affected by mechanical noise created by movement of the wires connecting the accelerometer to the ADC The experiment is conducted solely in order to validate our experimental data In the final system the wires from the accelerometer to the ADC the uC will be short and roughly immobile thus eliminating potential mechanical noise Materials e Accelerometer e ADC e Computer e ScopeLogger Procedure In all the measurements the accelerometer was placed in a vice ensuring that the accelerom eter was completely stationary Two measurements were then carried out First the signal carrying wires were left at rest and the signal from the two outputs where recorded During the second measurement movement where applied to the signal carrying wires thus disturb ing them as it is the case when a subject wears the wires during gait measurement The signals where recorded with ScopeLogger and then visualised in Matlab Results The results of the experiment can be seen in figure C 5 Discussion In figure C 5 it is clearly seen that the amplitude of all the signals are changing This must be interpreted as noise as the dynamic ac
123. s 11 The self test pin controls the accelerometer s self test feature When this pin is set to Vpp the resulting signal output is used to test if the accelerometer is functional The typical change in output is 0 290 g corresponding to 50 mV This pin can be left open circuit or connected to common in normal use In this application the self test pin is grounded see section 9 1 3 11 The Function of the ADXL311 Accelerometers are constructed in many ways Some use the piezoelectric effect they contain microscopic crystal structures that get stressed by accelerative forces which causes a voltage to be generated Another method is to sense changes in capacitance If two microstructures are placed next to each other they have a certain capacitance between them If an accel erative force moves one of the structures then the capacitance will change The ADXL311 senses changes in capacitance It consists of a variable differential air capacitor whose plates are etched into a suspended polysilicon layer The moving plate of the capacitor is formed by a large number of fingers extending from a beam a proof mass supported by tethers anchored to the substrate Tethers provide the mechanical spring constant that forces the proof mass to return to its original position when at rest or at constant velocity The fixed plates of the capacitor are formed by a number of matching pairs of fixed fingers positioned AO Chapter 9 Design and Implementa
124. s Point 61 if lid sPeerFrameSem else sJoinSemt return 0 The callback function identifies the received packet from ED as either a join request or a packet from an ED that has already established connection to the network If the received packet is from an already known ED lid 4 0 the sPeerFrameSem aphore will be incre mented If the linkID received is equal to 0 it will be identified as a join request and the sJoinSem aphore will be incremented Thus the ED sends a linkID of 0 until connection to AP has been established When ED has established connection to AP the AP assigns an incremental linkID to the ED sJoinSem After the network has been initialised the program enters a while 1 loop which runs an infinite number of times Thus the network will only be initialised once The following if statement will be entered when the sJoinSem aphore has been incremented in the sCB callback function and the number of EDs connected to the network is lower than the max number NUM_ CONNECTIONS which is defined in smpl_config dat to be eight connec tions by default if sJoinSem amp amp sNumCurrentPeers lt NUM_CONNECTIONS BSP_TURN_OFF_LED1 SMPL_LinkListen amp sLID sNumCurrentPeers sNumCurrentPeerst if sJoinSem sJoinSem After entering the loop the SMPL_LinkListen function will be called This function will not return until a successful link has been created When a succes
125. s in the ED is given see figure 9 9 Initialise Radio This function initialises the communication between both the uC and the CC2500 radio and the switches Initialise Micro Controller This function performs further initializations for the wC These include the DCO and MCLK are set to run at 8 MHz Timer A is set to trigger interrupts at 1 70 second intervals see appendix D for further explanation Initialise join network This function establish connection between ED and AP Link to Access Point This function sends a link request to the AP When the link request creates a successful link between the ED and the AP the ED becomes part of the network created by AP End Device Self Test This function tests whether the ED receives data from the accelerometer and whether the data is within acceptable limits If this is not the case the red LED will be turned on and indicate an error If the data is acceptable the green LED will be turned on If the uC is not initialised correctly no LEDs will be turned on Read Acceleration This function reads data from the accelerometer on port P2 0 and makes an A D conversion using a 10 bits successive approximation register ADC Filter Data This function filters the data using an IIR filter see section 9 3 44 Chapter 9 Design and Implementation Figure 9 9 The processes in ED is illustrated in a flowchart The arrows indicate the direction of the data flow The first interrupt from
126. s range from once a week to every day for a period Music therapy sessions typically last 20 30 minutes The music therapists see qualitative beneficial effects therefore they wish to propagate the therapy The effectiveness of music therapy has however not been proved with quantitative studies 28 The initiating problem is stated by the following question which through the problem ana lysis is discussed and clarified Does music therapy have an effect on patients with frontotemporal dementia Part I Problem Analysis Chapter 2 Method for Problem Analysis Problem Processing To achieve an understanding of the problem an analysis of the physiology of the patients with severe dementia with focus on the types of dementia that may lead to unwanted restless wandering is performed Furthermore an analysis of how music therapy improves the life quality of the patients is devised When the problem has been analysed it is summarised in a synthesis which leads to the problem statement Means to Carry Out the Problem Processing Knowledge about the characteristic physiological properties of the patients with different types of dementia that may lead to unwanted wandering is obtained through educational textbooks and articles Knowledge about existing methods and techniques for measurement of the activity level is likewise obtained through educational textbooks and articles Knowledge about the effects of music therapy on the life
127. s the main memory and the 256KB is for information memory The information memory is divided into four segments of 64 bytes each The only difference between these two memory sections are the size of the segments and the physical addresses In either section both code and data can be located Random Access Memory 1KB RAM is available on the MSP430f2274 Both data and code can be stored on the RAM module Operational Amplifier In the MSP430f2274 device there is implemented two identical operational amplifiers OA The OAs can be configured as an inverting amplifier a non inverting amplifier or combined with each other to form differential amplifiers With the OAFCx bits the amplifiers can be configured for different functions such as e General purpose opamp e Unity gain buffer for three opamp differential amplifier e Unity gain buffer e Comparator Appendix E MSP430f2274RHA 131 e Non inverting PGA amplifier e Cascaded non inverting PGA amplifier e Inverting PGA amplifier e Differential amplifier Timer A and B The uC contains two 16 bit counters timers A and B which each has three capture compare registers The registers can be used to generate interrupts in a chosen interval of time Timer A is used to control the frequency of the ADC conversions 21 22 Watchdog Timer The uC contains a watchdog timer which primary function is to perform a controlled system restart if a software error occurs This operation funct
128. sful link has been created the sNumCurrentPeers will be incremented and the sJoinSem aphore will be decremented and thereby be ready for a new ED connection sPeerFrameSem The following if statement will be entered every time the sPeerFrameSem aphore is incre mented in the sCB callback function This will happen every time AP receives a frame from ED 62 Chapter 9 Design and Implementation if sPeerFrameSem uint8_t msg MAX_APP_PAYLOAD len i for i 0 i lt sNumCurrentPeers i if SMPL_Receive sLID i msg amp len SMPL_SUCCESS while IFG2XUCAOTXIFG UCAOTXBUF msg 0 BSP_TOGGLE_LED2 sPeerFrameSem After entering the loop three variables are defined Then there is a for loop which runs a number of times equal to the number of EDs connected to the AP This loop separately receives data from the ED connected to the network The way this is done is by checking if the linkID message and length of message are received The statement UCAOTXIFG is set in the register IFG2 when the UCAO transmit buffer is empty This means that the program will enter the while loop IFG2 amp UCAOTXIFG and wait here until the buffer is empty and the flag is removed When the flag is removed the value from the array msg on place 0 is copied into the buffer This procedure is repeated 10 times to copy the entire array into the buffer not showed in the code Once the entire array have been copied the sPeerFr
129. sic therapy Afterwards the patient received music therapy for four weeks five times a week During the sessions the heart rate was measured An entire week after the last session the heart rate was measured again showing a significant fall in heart rate compared to the heart rate measured before the music therapy session This test has only been performed in a single case design on six patients and it is not enough to meet the requirements for entering the Cochrane database because the test has to be scientifically proved 38 clinical empirical studies made from 1986 to 1998 show that music therapy can be structured effectively to e g decrease behavioral problems 9 Even though music therapy seems useful on patients suffering from sorrow depression schizophren dementia or some other disorder it is not wide spread in Denmark In other countries music therapy are wide spread but in Denmark only about 12 students are ac cepted at the education in music therapy every year since 1982 80 of them graduate 7 Music therapy sessions are rather expensive because of the low numbers of therapists in Denmark Since the sessions are so expensive the relatives of the patient or the patient itself often would not pay the price for something which is not scientifically proved Chapter 5 Problem Statement 5 1 Synthesis of Problem Analysis The prevalence and incidence of dementia were estimated to 78 900 and 13 300 respectively in Denmark in
130. straight lines which represent the preset threshold values It is seen that the signal never intersects tresholdHS and that the baseline of the signal is positioned above thresholdTOFF Walking Laterally Walking Laterally Acceleration Signal thresholdHS thresholdTOFF Voltage v 1 3 F 7 12 fp E 1 1 AEAAAAA NAAA _ A AAA 250 300 350 400 450 Samples Figure 11 3 In the experiment where the subject walked laterally no heel strikes or toe offs were detected The figure contains the signal and two straight lines which represent the preset threshold values It is seen that the signal never intersects tresholdHS and that it has no general resemblance with the normal gait signal 11 2 Results 87 Walking with Knee Lifts Walking with Knee Lifts Acceleration Signal 4 thresholdHS thresholdTOFF Voltage V 0 8 1000 1050 1100 1150 1200 1250 1300 1350 Samples Figure 11 4 In the experiment where the subject walked with knee lifts only heel strikes were detected correctly No correct toe offs were registered The figure contains the signal and two straight lines which represent the preset threshold values Walking Backwards Walking Backwards Acceleration Signal thresholdHS thresholdTOFF Voltage V 250 300 350 400 450 500 560 Samples Figure 11 5 In the experiment where the subject walked backwards no heel strikes or toe offs wer
131. t should be over 3 V 1 Measure the total voltage of the three batteries used The output of the regulator should be 3 V 1 Apply different voltages to the regulator 2 Measure the output of the regulator 8 3 2 Evaluation Board Accelerometer Input on evaluation board accelerometer should be 3 V 1 Verify the output from the regulator is equal to 3 V Evaluation board accelerometer Output up to 3 V 1 Verify the input on evaluation board accelerometer is 3 V 2 The accelerometer can only give an output up to Vec hence the output will not exceed 3 V 34 Chapter 8 Specifications 8 4 Accept Test Software In section 8 2 a number of software specifications are introduced In this section it is explained how these specifications will be tested 8 4 1 Functional Requirements The functional requirements will be tested as follows It should be possible to detect strides taken by the patient and count these 1 Place system on person 2 Walk x number of steps 3 See how many strides the system has detected and counted It should be able to compare data regarding before during and after a music therapy session 1 Record data in three different times 2 Load data It should be able to perform self test on the system and indicate result to the user 1 Start up system 2 Perform self test 3 Observe result on LEDs It should be able to visualise potential errors 1 Disconnect the accelerometer from the
132. t signals it is inexpensive small and does not need complicated analogue signal processing In this project it is chosen to place the accelerometer on the ankle because it is out of reach of the patient Also it is chosen to do the test with bare feet and on a hard surface Chapter 8 Specifications 8 1 Hardware Specifications The purpose of this chapter is to set the specifications for the hardware of the system Figure 8 1 shows an overview of the system where the hardware part is specified Accelerometer and Evaluation board The accelerometer used in this project is the ADXL311 The ADXL311 is capable of mea suring both positive and negative accelerations to at least 2 0 g see appendix C 1 for further explanation The accelerometer is mounted on an evaluation board which has an adjustable bandwidth provided by a 1 order low pass filter for further explanation see section 9 1 3 The bandwidth is set to 20 Hz to minimise noise and to avoid aliasing e Evaluation board accelerometer input from power supply 3 V e Accelerometer output range at Vag 3 V 1 152 1 848 V e Accelerometer current consumption typical current consumption at 3 V is 400 yA e Evaluation board bandwidth 0 20 Hz Micro Controller and Evaluation Board The pC used in this project is MSP430f2274RHA The uC is mounted on an evaluation board named eZ430 RF2500 e uC signal input range 0 Vec e uC current consumption Active Mode 2
133. tance of 13 meters in 9 71 seconds hence walking with a average velocity of 1 34 m s or 4 8 km h The results of the test can be seen in table 11 3 Event Visually True Deviation False Percentage Registered Registered Registered False of True Heel Strikes 9 8 11 1 4 50 Toe Offs 8 1 87 5 1 100 Strides 11 8 37 5 Table 11 3 High Velocity The first column shows the type of gait event or parameter The second column shows the number of visually identified gait events the true number The third column shows the number of gait events registered correctly by the system The fourth column shows the deviation between the second and the third column The fifth column shows the total number of the different events registered by the system that is the number of correct identifications plus the number of incorrect identifications The sixth column shows the number of gait events registered by the system which did not take place The seventh column shows the percentage of incorrect identifications compared to correct identifications 86 Chapter 11 Test of the Entire System Walking on the Front of the Feet Walking on the Front Feet Acceleration Signal thresholdHS thresholdTOFF Voltage V 200 250 300 350 400 450 500 Samples Figure 11 2 In the experiment where the subject walked on the front of the feet no heel strikes or toe offs were detected The figure contains the signal and two
134. ter and the wC run on the same power supply the signals from the accelerometer are not able to exceed Vcc 3 V Therefore it is possible to connect the output from the accelerometer directly to the input pins of uC the without electrical protection The port chosen for this purpose is P2 0 AO which is available at pin 3 The connection between PC and AP is set with port P3 4 as output from AP and P3 5 as input 20 Universal Serial Communication Interface UART mode A Universal Asynchronous Receiver Transmitter UART is used to implement serial com munication The universal serial communication interface USCI supports two modes The synchronous peripheral interface SPI mode and the asynchronous UART mode In SPI mode the uC can communicate with several extern systems and in UART mode it can only communicate with one extern system In this project it is only necessary to communi cate with the PC and therefore the UART mode is chosen To transmit and receive data between the wC and the PC the UART mode is used see ap pendix E When the uC is in the UART mode the USCI transmits and receives characters at a bit rate which is asynchronous to the other device The time for each character is based on the selected baud rate of the USCI which is the speed the uC can transmit with The transmit and receive functions use the same baud rate frequency The UART character format consists of a start bit seven or eight data bits an even odd no p
135. that identifies the heel strikes The loop runs as long as the current sample number i is lower than the total number of samples a It is examined if the value of the current sample xout is lower than a preset threshold value thresholdHS If xout is higher than or equal to thresholdHS the next sample is examined by incrementing i If xout is lower than thresholdHS p is assigned the value of i 1 Now it is examined if xout is lower than the value of the sample q 1 p If xout is higher than or equal to q 1 p the next sample is examined by incrementing i up by one If xout is lower than q 1 p the value stride is added by one the point of the heel strike is registered by assigning the value HS stride with the value of i and 21 is added to i to skip analysis of the oscillations following the heel strike the delay of the detected heel strike see section 9 5 To identify the toe off a threshold is set in Matlab See thresholdTOFF in figure 9 17 The toe off occurs in the time span between one particular heel strike HS h and the suc cessive heel strike HS2 h HS is already identified and HS2 is found simply by assigning it with the value corresponding to HS h 1 Matlab is set to search for the toe off between HS h 21 and HS2 h 21 thus narrowing the search field see figure 9 17 When the value of the acceleration signal is higher than the threshold value it is compared if each current value is higher than its successive
136. tion on either side of the moving fingers attached to the beam and anchored to the substrate see figure 9 4 8 Tether Beam Fixed Anchors Outer Plates Figure 9 4 Model of a acceleration sensor during zero acceleration 8 When responding to an applied acceleration or under gravity the proof mass inertia causes it to move along a predetermined axis relative to the rest of the chip As the fingers extending from the beam move between the fixed fingers capacitance change is being sensed and used to measure the amplitude of the force that led to the displacement of the beam In other words as soon as the chip experiences acceleration the distance between the fixed plates and the movable plates increases At the same time the distance between the other fixed plate and the movable plate decreases resulting in capacitance imbalance see figure 9 5 8 Applied Acceleration Beam Motion Figure 9 5 Model of a acceleration sensor during acceleration 8 To sense the change in capacitance between the fixed and moving plates two square wave signals of equal amplitude but 180 out of phase from each other are applied to the fingers forming the fixed plates of the capacitor At rest the space between each one of the fixed plates and the moving plate is the same and both signals are coupled to the movable plate where they subtract from each other resulting in a waveform of zero amplitude During accele
137. to be found or else this function will not work In section 7 7 it was chosen to do tests with bare feet on a hard surface This means that the system not has been tested on different surfaces and with footwear yet This might be a source of error since the patients do not walk around in bare feet all the time and they also walk on different surfaces as carpets gravel etc The data analysis is not calibrated for these conditions and therefore the system is not capable of executing the data analysis Sampling Frequencies and Filtration Even though the patients walk normal the system may loose data see section 11 2 or figure 12 1 ot 3 4 120 bei pt N ur J 100 F 4 90 4 70 f 1 1 1 1 1 f 1 820 840 860 880 900 920 940 960 980 Figure 12 1 A portion of the signal when the subject was walking at normal speed approx 3 km h The signal shows two heel strikes and two toe offs It starts with a heel strike at sample number 840 and there is a heel strike again at sample number 920 In figure 12 1 two heel strikes and two toe offs are shown At the first heel strike it is easy to see that there is a peak down to 70 and up to 170 This peak is what the data analysis is using to find the heel strikes At the other heel strike at about 920 samples there is no peak so the data analysis cannot find the heel strike at this point This is problematic because if the system cannot find a heel strike it cannot find the
138. to register when a specific step is performed 19 20 Chapter 7 Methods to Measure Level of Activity 7 2 Goniometer A goniometer is an instrument for measuring the angle over a joint e g elbow knee hip or ankle By placing a goniometer at the knee ankle or hip joint it is possible to register each time a stride is performed Thereby it is possible to register whether the subject is walking or not Furthermore it would be possible to analyse the output using e g Matlab to determine how fast the patient walks but not the distance covered There are some limitations when using the goniometer on this group of patients As described in chapter 3 some of the patients will remove the goniometer if they find it annoying Therefore it will not be possible to use a goniometer placed at the hip and possibly not at the knee By placing it at the ankle joint less of the patients would be able to reach the goniometer and remove it The goniometers available for this project are the SG150 and SG110 A from Biometric Ltd The weight of these models are 19 g and 20 g respectively and can be mounted using double sided tape The lifetime of the sensors is approximately 600 000 cycles The goniometers all functions the same way only differentiating in size to fit different joints SG150 is specialised for the hip and the knee The SG110 A is used on the ankle where the measured output is dorsiflexion plantarflexion and inversion eversion movements The
139. ty Furthermore the test should make it possible to decide how to orientate the accelerometer in the most reasonable way Material e ADXL203 1 7 g accelerometer e ADXL311 2 0 g accelerometer e Double sided tape e Lineariser e Nine volt battery e Channel distributer e Evaluation board ADXL311 EB e Evaluation board ADX203 EB e ADC USB6009 e PC e Treadmill 109 110 Appendix C Pilot Experiments a b c Figure C 1 The orientations of the accelerometer Procedure One subject was tested Three orientations of the two accelerometers were tested At first the accelerometer was placed like in figure C la on the ankle Four velocities were used No movement one four and six km per hour Each signal was recorded between 10 and 15 seconds The signal was sampled by the ADC and saved on the computer using ScopeLogger The same procedure was performed when orienting the accelerometer as shown in figure C 1b and afterwards as shown in figure C 1c After the measurements were carried out the data were processed in Matlab Results In figure C 2 and C 3 results from the test with the 1 7 g and 2 0 g accelerometer can be seen In the figures the max and min output voltages can be seen At four km per hour with the 1 7 g accelerometer the signal is saturated which can be seen by the flat peak instead of a tip At six km per hour using the 2 0 g accelerometer the signal is not saturated and it has a tip instead of a flat pea
140. uation board while keeping the accelerometer at rest in five different orientations The accelerometer was battery supplied through the voltage regulator ensuring a Vag of 3 00 V The orientations and the corresponding output voltages can be seen in figure 10 1 The theoretical output responses at Vag 3 00 V can be seen in section 9 1 2 in figure 9 2 In the test where the accelerometer is oriented with both the X axis and the Y axis hori zontally the response from the respective axes should in theory be identical and equal to Yaa In this test ay 1 50V as neither of the axes are subjected to gravity and 0g Maa As seen in figure 10 1 this is not the case When the accelerometer is oriented with both axes horizontally and at rest non of the axes are affected by acceleration or grav ity hence the output response of the axis is corresponding to 0 g The output voltage of the Y axis is the expected 1 50 V The output response of the X axis however is 1 44 V The reason for this anomaly could be the degree of accuracy in the test It is difficult to determine whether the small 5 mm 5 mm accelerometer is mounted completely in paral lel to the surface of the evaluation board If it is not this would have an effect on the results The theoretical output sensitivity of the accelerometer is 174 mV g at Vag 3 0V To find the real output sensitivity the following calculations are carried out The output response of the X axis at 0 g
141. when passing through the filter After the coefficients were found the phase response were checked out see figure 9 14 and so were the poles and zeros in the z plane see figure 9 15 1 fi fi 05 o 05 1 Real Part Figure 9 15 The pole the cross and zero the dot in the z plane which shows that the filter is stable since the pole is in the left half plane and lay inside the unit circle Implementation Below the filter code can be seen The flow diagram 9 16 shows what the code does step by step define FILTER_LENGTH 3 float x FILTER_LENGTH 0 0 0 float y FILTER_LENGTH 0 0 0 float a FILTER_LENGTH 1 0 1126 float c FILTER_LENGTH 0 5563 0 5563 int n 58 Chapter 9 Design and Implementation x 2 templcounter y 2 c 0 x 2 c 1 x 1 a 1 y 1 for n 0 n lt 1 n x n x n 1 yn y n 1 x 2 temp counter tmp counter signed char y 2 Figure 9 16 The flow diagram shows the code step by step from when the input is retrieved until the filter is done processing it First X and Y where X is the input and Y is the output are set to an array of three zeros so that the filter equation has some previous values for both input and output in the beginning Afterwards the filter coefficients a and c are stated x 2 temp counter gets a value which is sent through the filter equation The value y 2 is first put in an array on the second place to be
142. who suffer from frontotemporal dementia often have tendency to wander restless around The prevalence and incidence of dementia in general were estimated to 78 900 and 13 300 respectively in Denmark in 2004 3 Frontotemporal dementia counts for approxi mately 5 10 of the cases 26 In Denmark treatment of patients with severe dementia has mainly been based on medica ments It is critical that the medication is dosed to each patients personal demand This however can cause some patients to be over medicated Over medication may cause the pa tients to fall which can result in broken bones and loss of teeth 1 Furthermore over medi cation can cause sedation of the patient which is ethically problematic 43 The medicine can cause an inhibition of the restless wandering which is positive but the sedative effect of the medicine also affects the general activity level of the patients It is healthy for the patients to walk only the restless wandering is harmful to the patients 1 Alternative treatments are therefore desirable Music therapy is an acceptable method for treating dementia with no ethical issues and without the use of medication The object of music therapy is to create contact to the pa tients and establish communication with the patients who are unable to or do not dare to express themselves 28 Depending on how severe the dementia is the number of sessions needed is assessed by the music therapist The number of session

System to Monitor the Level of Activity of People with Severe

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