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1. The installer is ready to install Setup on your computer Click Next to start the installation Cancel lt Back New A4 MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY APPENDIX Step 6 Application Install Security Warning A new installation window will appear showing a security warning Click Install to continue Peck cya Cd Name PressureSensor3 From C Program Files Griffith University Setup1 Publisher Unknown Publisher msa oon While applications can be useful they can potentially harm your computer If you do not trust the source do not install this software More Information Step 7 i Setup1 i p ojx The program will deploy and a confirmation screen will pop up showing that the program Installation Complete ge has been successfully installed in your computer Click Close to finish Setup has been successfully installed Click Close to exit Please use Windows Update to check for any critical updates to the INET Framework cot ee G JOURNAL OF ORTHOPAEDIC 3 SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 A5 __ __ TECHNICAL NOTE APPENDIX SETUP AND CALIBRATION Step 1 See Oe este To run the program simply go to Start gt Programs gt Griffith University and click on 3 Pressure Sensor 3 1 Step 2 HE Griffith University Australia2. MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY APPENDIX IMPORTANT If you experience problems during the calibration the value saturates even ifn ol x if you reduce the volume of your computer headphone jack you may need to alter the volume and or remove the boost of your microphone In order to do this go to Sound Options Help and Audio Devices Properties click on the Audio tab as described in step 2 and click on the Volume button of the Sound Recording The following control window will appear cue You can then alter the microphone volume Babri p 4 Volume V Select SoundMAX HD Audio To deselect the boost click in the Options menu and select Advanced Controls as shown E lol x Options Help Advanced Controls JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 AQ __ __ TECHNICAL NOTE 2 A new Advanced button at the bottom of the control window will appear Eee olx Options Help Click on it to access the Advance Controls for Microphone control window Deselect the Microphone boost as shown Et These settings can be used to make fine adjustments to your audio Tone Controls These settings control how the tone of your audio sounds Other Controls These settings make other changes to how your audio sounds See your hardware
3. _ _ TECHNICAL NOTE NEIL TUTTLE BSc GradDipAdvManipTher MPhil PhD e GUILLERMO JACUINDE MEngTech Design and Construction of a Novel Low Cost Device to Provide Feedback on Manually Applied Forces hysical therapists commonly use their hands to perform manual therapy techniques While the magnitude of the force applied during these techniques is thought to be important itcan vary between practitioners by as muchas 500 and sometimes approach potentially dangerous levels Providing students with contemporaneous feedback is one method that has been shown to improve the consistency of force application 7 Providing feedback for students is complicated by the nature of the tech niques performed Therapists typically use multiple points of contact with both hands while maintaining adequate sup port and control to produce the desired movement Some investigators have eval uated the net applied load by measuring STUDY DESIGN Design and evaluation techni cal note OBJECTIVES To describe the design of a simple low cost device for providing feedback of manually applied forces to the cervical spine and to assess the device against specific design criteria BACKGROUND The forces applied during manual therapy may vary by as much as 500 between practitioners But consistency can be improved in students when they are provided with contemporaneous feedback The current methods of providing feedback howe
4. Calibrate before each use WARNING This step will produce a high pitched sound coming out from your computer STEPI Pace oad ot apmroinatsy sigcv snr Nm speakers e Terpet ewons D E emene Press the Start button A high pitched sound will come out from your computer s speak 10 m ers If you can hear the sound please go to Step 3 f 20 NOTE If you cannot hear the sound 25 a e Unmute the computer o s e Adjust the volume Software by G JacuindeandN Tuttle Raw Count 0 Pouse NOTE If you still cannot hear the sound after the previous adjustments e Check the setting of your sound card e Open the Control Panel by going to Start gt Settings gt Settings gt 1 Control Panel gt Control Panel OH 42 ala Ln 66 Coll REC Windows XP Professid Once the Control Panel is opened double click in Sound and Audio Devices D search gt Foes S X 1 Er 70 Address G Control Panel amp Accessiblity Options Adjust your computer settings for vision hearing and mobity Instals and troubleshoots hardware and Windows components Z Add Hardware and Add or Remove Programs Instal or remove Administrative Tools Configure administrative settings for your computer Set up Windows to updates Tuning Adjust your text for easier K Configuration Manager View or Edt Configuration Manager settings for this computer 2 Date and Time Set the date time and time zone f
5. In addition JOSPT offers easy online access to special issues and features including a series on clinical practice guidelines that are linked to the International Classification of Functioning Disability and Health Please see Special Issues amp Features in the right hand column of the Journal website s home page JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 179 __ _ TECHNICAL NOTE INSTRUCTIONS Step 1 List of materials 1 Audio lead 3 5 mm 1 8 in stereo male to 3 5 mm stereo male plug 2 Strip connector block 3 Lead with 3 pin female plug square pin at 2 54 mm 0 1 in centers In this case Zalman ZM EC1 extension lead for computer fan Flexiforce A201 1 lb sensors Thin steel or brass washers 8 to 9 mm outer diameter 9 mm diameter silicone bumpers or thin washers of no more than a 9 mm outer diameter 7 Epoxy glue 8 Electrical tape or 2 short lengths of heat shrink 9 Wire clippers 10 Small screwdriver en ay SS Step 2 1 Glue washer to back side of sensor ensuring that the center hole is filled to produce a flat surface 2 Either attach self adhesive bumper or glue small washer to front of Flexiforce A201 ensuring that it does not extend beyond the active colored area JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 Al J TECHNICAL ore _ Step 3 1 Cut
6. radio button gt Advanced Ensure the microphone boost box is NOT selected Advanced Controls for Microphone zg These settings can be used to make fine adjustments to your audio Tone Controls These settings control how the tone of your audio sounds Bass Low High i 1 Low ee High Other Controls These settings make other changes to how your audio sounds See your hardware documentation for details 1 Microphone Boost JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 A3 __ _ _ _ TECHNICAL NoTE APPENDIX INSTALLATION INSTRUCTIONS Step 1 Once you have downloaded and saved the file double click on Pressure Sensor zip to extract the files Step 2 Once the files have been extracted navigate inside the Release folder and double click on setup exe Step 3 Read the license agreement select either I Agree or I Do Not Agree and click Next Step 4 Select the installation folder and the appropriate users in case there is more than one person using the computer To continue click Next Step 5 Click Next to confirm the installation Fle Edt Vew Favortes Toos Help QO pack O FP search E gt roders L5 gt X 19 Fay Address C Downloads Users Manual Template Folders x Name See Type Date Modified Desktop a D Pressure Sensor zip 3 983 KB Comp
7. audio lead in middle 2 Cut back 25 mm 1 in of outer insulation 3 Cut off outer wire shield and or foil shield Ensure that this shield does not contact the other wires Electrical tape or heat shrink may be useful here 4 Strip insulation from about 12 mm in of each of the inner insulated wires and twist together the 2 wires on each cable usually 1 red and 1 black NOTE The 2 halves of the audio cable will be identical but separate Step 4 1 Cut fan cable near male plug leaving a long length attached to the female plug 2 Clip off the middle red wire from the female plug leaving the 2 outside wires white and black 3 Strip insulation from about 12 mm 1 2 in off the ends of the white and black wires A2 MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY APPENDIX Step 5 1 Cut 2 sections off the connector block strip 2 Connect the 2 wires from the fan cable and the twisted wires from 2 of the audio cable to each side of the connector block NOTE These wires can be soldered rather than using screw connectors Baked Step 6 1 Plug sensor into female 3 pin plug 2 Plug 1 of the 3 5 mm audio leads into the headphone socket and the other into the mic socket on your computer If prompted select microphone as the input 3 Ensure microphone boost is off Double click on volume icon Click Options gt Properties gt select the Recording
8. magnitude RESULTS Accuracy HE MEAN SD DIFFERENCE BE tween the applied load and the reading on the device was 0 20 2 00 N or 0 3 14 9 The limits of agreement that indicate how closely 95 of measurements would be expected to approximate the actual applied load were 3 8 to 4 2 N or 29 5 to 30 1 Bland Altman plots show that the lim its of agreement in Newtons remained consistent from 5 to 45 N FIGURE 5A When expressed as percentages the dif ferences decreased with increasing force FIGURE 5B Due to the large percentage differences for forces of 5 N the limits of agreement in percentage were calculated for forces from 10 to 45 N as 22 6 FIGURE 5B The repeatability coefficients indicating the maximum difference be tween 95 of repeated measurements were 2 0 N or 12 1 FIGURE 6 Comparison With Design Criteria The device met most of the design crite ria 1 It was easy to use and calibrate with calibration taking less than a min ute 2 It cost less than 100 US dollars having been produced for approximately 30 US dollars 3 It allowed the tech niques to be performed in as normal a way possible as it could be placed be tween the patient and different parts of the therapist s hand and was thin enough 3 mm thick if 2 washers were used and 8 mm thick if 2 bumpers were used to be used with the therapist s hands in normal positions for most techniques 4 It was able to provide real t
9. the parameter of interest eg assessment of pressure pain thresholds or palpation of soft tissue swelling tender ness or surface anatomy For FSRs to measure force pressure must be evenly distributed over the sensor area using pucks such as the washers and bumpers used in the current device The device described in this paper minimizes the complexity cost and difficulty of use at some expense of ac curacy and range Though the device is configured for a specific purpose dis cussions with colleagues have raised a number of applications for which simi lar devices might be used These range from assessing forces applied through partial weight bearing casts to teach ing postural drainage for premature in fants The relatively slow response time of FSRs does not significantly affect their accuracy at loading rates commonly used in mobilization less than 2 Hz but could result in underestimation of force during more rapid techniques such as high velocity thrusts Hall et alf provide an in depth description of more complex configuration calibration and prepara tion procedures used for FSRs to maxi mize dynamic range and accuracy There are a variety of configurations between those used in this study and those de scribed by Hall et al that can be adapted for specific applications Some configura tions include using 1 a range of sensors to assess forces from tenths to hundreds of Newtons or applied over large
10. therapists during spinal mobilization Clin Biomech Bristol Avon ISSIR SoS Harms MC Milton AM Cusick G Bader DL Instrumentation of a mobilization couch for dynamic load measurement J Med Eng Technol 1995 19 119 122 Keating J Matyas TA Bach TM The effect of training on physical therapists ability to ap ply specified forces of palpation Phys Ther 1993 73 45 53 Lee M Moseley A Refshauge K Effect of feed back on learning a vertebral joint mobilization Skill Phys Ther 1990 70 97 102 discussion 103 104 Marcotte J Normand MC Black P Measurement of the pressure applied during motion palpa tion and reliability for cervical spine rotation J Manipulative Physiol Ther 2005 28 591 596 http dx dol org 10 1016 j jmpt 2005 08 003 Snodgrass SJ Rivett DA Robertson WJ Calibra tion of an instrumented treatment table for measuring manual therapy forces applied to the cervical spine Man Ther 2008 13 171 179 http dx doi org 10 1016 j math 200704 002 Snodgrass SJ Rivett DA Robertson VJ Sto janovski E A comparison of cervical spine mobilization forces applied by experienced and novice physiotherapists J Orthop Sports Phys Ther 40 392 401 http dx doi org 10 2519 jospt 2010 3274 11 12 13 14 15 16 Snodgrass SJ Rivett DA Robertson VJ Sto janovski E Forces applied to the cervical spine during posteroanterior mobilization J Manipula tive Physiol Ther
11. 2009 32 72 83 http dx doi org 10 1016 j jmpt 2008 09 012 Sran MM Khan KM Zhu Q McKay HA Oxland TR Failure characteristics of the thoracic spine with a posteroanterior load investigating the safety of spinal mobilization Spine Phila Pa 1976 2004 29 2382 2388 Tekscan Inc FlexiForce Sensors User Manual Available at http Avww tekscan com pdfs FlexiforceUserManual pdf Accessed 2010 Tuttle N Barrett R Laakso L Posteroanterior movements in tender and less tender locations of the cervical spine Man Ther 2009 14 28 35 http dx doi org 10 1016 math 2007 09 003 Tuttle N Barrett R Laakso L Relation between changes in posteroanterior stiffness and ac tive range of movement of the cervical spine following manual therapy treatment Spine 2003 33 E67 3 679 Waddington GS Adams RD Initial development of a device for controlling manually applied forces Man Ther 2007 12 133 138 http dx doi org 10 1016 j math 2006 06 009 MORE INFORMATION WWW JOSPT ORG BROWSE Collections of Articles on JOSPT s Website The Journal s website www jospt org sorts published articles into more than 50 distinct clinical collections which can be used as convenient entry points to clinical content by region of the body sport and other categories such as differential diagnosis and exercise or muscle physiology In each collection articles are cited in reverse chronological order with the most recent first
12. der the therapist These methods can accurately measure the net applied load but may not reflect the load applied to the structures of interest In addition these methods of measuring the net load are expensive and electronically and procedurally com plex Other investigators have measured the load applied at a single point the simplest example of which employed a hand dynamometer interposed between the therapist and the patient A sensor positioned between the therapist and the patient can accurately measure the load applied locally but a dynamometer due to its size may prevent the evaluation of some techniques and significantly alter the performance of others Although not reported as a means to provide feedback another method of as sessing forces applied at a single point of contact is the use of thin flexible force sensing resistors FSRs which mini mize interference with the therapist s performance of techniques and sensitiv ity FSRs have a reported repeatability of approximately 5 which would be more than sufficient to provide feedback for students however the accuracy of the system described would likely be re SUPPLEMENTAL VIDEO ONLINE 1Senior Lecturer in Musculoskeletal Physiotherapy School of Physiotherapy and Exercise Science Gold Coast Campus Griffith University Queensland Australia Senior Scientific Officer School of Physiotherapy and Exercise Science Gold Coast Campus Griffith Univers
13. documentation for details 1 Microphone Boost S Local Disk C Recordin Data Q pack O gt 3 search i routers gt gt X 19 Fe IMPORTANT If you need to record the data from the device first you have to create a new Ome ee ie 2 folder using Windows Explorer Open Windows Explorer and select the C drive Backup BJPrinter Calibration Data AlO MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC SPORTS PHYSICAL THERAPY APPENDIX Go to File gt New gt Folder and rename the new folder Force_Data Greate Shortcut Delete The system is ready to record your data in a coma separated value format csv which e Ne A Fi can be opened using Excel You can find your data files in the following directory C a STEP1 Place load of approximately 4 kg over sensor Force_Data To start recording simply press the Start Data Recording button To stop ee press the Stop Data Recording button To stop the high pitched sound press the pause ii n ae button remember that it will stop the data acquisition JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 All
14. dollars 3 allow the techniques to be performed in as normal a way as possible 4 be able to provide real time and archived feed back on force magnitude within 20 or 5 N for forces up to 45 N and 5 be constructed from readily available parts without requiring specialist skills The aim of this paper was to describe the design construction and repeatabil ity of measurements of this device and to assess the device against the stated de sign criteria METHODS Device Construction SRS ARE THIN 0 2 MM THICK LOW cost pressure sensors whose re sistance decreases with pressure applied on the sensor surface We used Flexiforce A201 sensors Tekscan Inc South Boston MA which are rated as having a 1 lb 0 454 kg range and a 9 53 mm diameter active area Glued to 2 sides of the sensor are rounded silicone bumpers and or metal washers to ensure that force is distributed over a constant area During development of the device we collected pilot data to determine what type of pucks when attached to the sen FIGURE 1 The components used to construct the device The parts shown are 1 an audio jumper lead with 2 male 3 5 mm plugs cut in half and wire ends stripped 2 a 2 element screw connector 3 a Zelman ZM EC1 cable Zalman USA Inc Garden Grove CA with the male plug removed and wire ends stripped and 4 a Flexiforce A201 1 lb sensor Tekscan Inc South Boston MA with an 11 mm diameter was
15. ect the device to the microphone and headphones jacks on your computer as shown in the picture If prompted by an audio system event pop up menu select microphone as the input Step 4 GS Griffith a E Tae Press down the force sensor resistor with your finger and check for any change in the raw SED Pn tpi stwora count value as shown m 2 a Start Data Stop Data Recording Recording Software by G Jacuindeand N Tuttle Rew Count 98 Pouse JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 A7 __ __ TECHNICAL NOTE 2 Step 5 Calibration Calibration is accomplished by applying a known load of 30 to 40 N to the sensor A 4 kg weight equals 39 2 N A full 4 L or 1 gal plastic drink bottle as shown at right produces loads of approximately 39 5 or 37 5 N respectively Once the known weight is placed on top of the force sensor resistor adjust the volume until you get the corresponding value on the graph sriffith Univer Australia Calibrate before each use Newtons STEP1 Place load of approximately 4 kg over sensor STEP2 Adjust volume until the output in Newtons is correct 1kg 9 8 Newtons 38 6 Force Force Pounds Target Newtons fp a Newtons 10 40 75 30 R 20 25 10 OF Time Seconds 5 Start Date Stop Data Recording Recording Software by G Jacuindeand N Tuttle Rew Count 215 Pause A8
16. es applied during motion palpation of the cervical spine ranged from 4 0 to 41 N cm One strength of the device is that it directly measures the force between the user and the patient however as a result it cannot measure net forces that include all points of contact Nor can its mea surements include contact between the user and patient that extends beyond the sensor such as other parts of the finger thumb or hand Compared to the device presented in this technical note other de vices used to provide feedback are more accurate and applicable over a larger range of forces but these are at least an order of magnitude more expensive and Difference From Applied Load N Applied Load N Difference From Applied Load 30 Applied Load N MMMM MlM FIGURE 5 Bland Altman plots of accuracy across all sensors computers and repeated trials For both plots the y axis indicates the difference between applied load and measured load with A differences in Newtons and B in percentages Dashed lines indicate the 95 limits of agreement The limits of agreement are shown for forces of 9 8 N and above due to the large variation with the lower load interfere more with the performance of techniques Force Versus Pressure There is an important difference be tween force as we have considered it up to this point and pressure as discussed by Marcotte et al Force is the relevant parameter if the movement o
17. f a vertebra is thought to be related to the magnitude and direction of the applied force Pres sure which is defined as force per unit area may be the relevant parameter with respect to tenderness eg pressure pain threshold or soft tissue characteristics such as swelling or lymphoedema The characteristics of FSRs are such that their resistance changes in response to the maximum pressure at any point on the sensor area Marcotte et al who used bare unmounted sensors rightly described their results as pressure rather than force We produced the effect of varying the distribution of force across a sensor by using either the pad or a fin gertip to apply force to an FSR resting on a scale to reach a series of target values The resistance of the bare FSRs differed by as much as 100 when pressure was applied by different parts of the finger JOURNAL OF ORTHOPAEDIC SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 177 Difference From Mean N o Mean Force N Difference From Mean 30 Mean Force N ees FIGURE 6 Bland Altman plots of repeatability for trials using the same condition same sensor and computer The y axis indicates the difference between measured load and mean for that condition shown on the x axis with A differences in Newtons and B in percentages Dashed lines indicate the 95 repeatability coefficients Therefore bare FSRs may be useful when pressure is
18. her affixed to one side by epoxy adhesive and a 79 mm diameter self adhesive silicone bumper Bumpon SJ 5302 3M St Paul MN on the other More detailed instructions for construction are contained in the APPENDIX available online at www jospt org The device is symmetrical so either plug can be inserted into the headphone socket and the other into the microphone socket on a PC or laptop sor would result in consistent changes in resistance of FSRs and to ensure that the silicone bumper and washer performed similarly whether forces were applied over soft tissue or bony prominences A typical configuration used for perform ing computer based measurements with an FSR includes external electronic components to condition the signal an analogue to digital converter to inter face with the computer and software to process the data We used simple wir ing without additional electronic compo nents and the computer s soundcard in place of an external analogue to digital converter Custom software was devel oped for signal processing which pro duces a continuous 1000 Hz sine wave output from the computer headphone jack The signal passes through the FSR and the modified signal returns via the microphone jack such that the FSR es sentially acts as a volume control The software reads the intensity of the re turn signal converts the value to a force equivalent and displays the force both as an instantaneous value and a time ser
19. hysical therapy students to perform manual techniques on the cervical spine The device met each of its design criteria as it was simple to use and calibrate cost less than 30 US dollars enabled a variety of techniques to be performed in a clinically relevant 178 MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC SPORTS PHYSICAL THERAPY manner provided both real time and ar chived feedback on force magnitude and was constructed from readily available materials without specialist skills It is anticipated that this and similar devices may be useful across a variety of appli cations in addition to teaching manual therapy skills 1 Chang JY Chang GL Chien CJ Chung KC Hsu AT Effectiveness of two forms of feedback on training of a joint mobilization skill by us ing a joint translation simulator Phys Ther 2007 87 418 430 http dx dol org 10 2522 pt 20060154 2 Chiradejnant A Maher CG Latimer J Develop ment of an instrumented couch to measure forces during manual physiotherapy treatment Man Ther 2001 6 229 234 http dx dol org 10 1054 math 2001 0418 3 Hall RS Desmoulin GT Milner TE A technique for conditioning and calibrating force sensing resistors for repeatable and reliable mea surement of compressive force J Biomech 2008 41 3492 3495 http dx doi org 10 1016 j jbiomech 2008 09 031 10 Harms MC Bader DL Variability of forces ap plied by experienced
20. ies graph A target force level can be displayed on the graph and if required Flexiforce sensor FIGURE 2 Wiring diagram One plug is inserted into the headphone socket and the other into the microphone socket of a standard computer soundcard The output from both channels of the headphones goes through the sensor and the modified signal returns as input to the microphone socket Note that a few computers with low specification sound cards will not produce sufficient power to operate the device fil Griffith University Australia Calibrate before each use STEP1 Place load of approximately 4 kg over sensor STEP2 Adjust volume until the output in Newtons is corect 1kg 9 8 Newtons 0 0 Force Target Newtons 27 4 Newtons FIGURE 3 Screenshot of the software in operation The force is shown in Newtons on the top right and a 5 second history of the applied force is shown on the graph A target force can be included on the graph and appears as a red horizontal line Start data and stop data recording buttons enable the data to be saved for viewing or analysis at a later time Sofware by G Jacuinde ar N Tuttle Raw Count 0 the force data can be saved for review The device the wiring diagram and a screenshot of the software are shown in FIGURES 1 2 and 3 respectively The APPENDIX available online at www jospt org presents a simple method of con struction that does not require any skills beyond c
21. ime and archived feedback on force magnitude within 20 or 5 N for forces up to 45 N with 176 MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY contemporaneous visual feedback and feedback from applied force data stored for later evaluation Its accuracy was within the design criteria except that the percentage variability for forces below 5 N were greater than the specified 20 5 It was either available off the shelf or could be constructed from readily avail able parts without specialist skills the device was made from parts that were readily available from electronic suppli ers and did not require specialist skills to construct DISCUSSION HE DESCRIBED DEVICE PROVIDES A low cost practical method for mea suring forces manually applied through 1 point of contact and is consid ered capable of providing useful feedback for students learning manual therapy skills The device is able to assess forces applied at 1 point and is only accurate over a relatively narrow range of forces 5 to 45 N A maximum force of 45 N was selected because the device was de signed primarily for use with the cervical spine Our previous research found that changes in stiffness of the cervical spine related to patient symptoms occur at forces as low as 4 N and predominantly at those below 25 N These findings are consistent with those of an earlier study by Marcotte et al who found that pres sur
22. instaled Symantec LiveUpdate This applet allows you to configure your LiveUpdate See information your computer system and change settings for hardware performance and automatic updates ek Taskbar and Start Menu Customize the Start Menu and the taskbar such as the types of Rems to be displayed and how they should appear 8 User Accounts Change user account settings and passwords for people who share this computer F windows CardSpace ane KE O register with websites and online services Windows Firewall Configure the Windows Firewall lt 2 Wrreess Network Setup Ward Set up or add to a wireless network for your home or office A6 MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY APPENDIX On the Sounds and Audio Devices Properties dialog box click on the Audio tab Select 2x the appropriate devices for your computer for Sound playback and Sound recording Volume Sounds Audio Voice Hardware NOTE if you have more than one sound card in your computer you should select the EER card with your microphone and headphone jacks on the front of your computer Defaut device SoundMAX HD Audio v Volume Advanced Sound recording Ay Default device o E Volume Advanced MIDI music playback Fas Default device Microsof GS Wavetable SW Synth z Volume About Use only default devices Step 3 Conn
23. ity Queensland Australia No grant support was received for the material presented in this manuscript The authors do not have a financial interest in the device or any components used in its construction Readers should ensure the suitability of the device for their computer before installing and using the device described in this article Address correspondence to Dr Neil Tuttle School of Physiotherapy and Exercise Science Griffith University Gold Coast Campus Queensland 4222 Australia E mail n tuttle griffith edu au 174 MARCH 2011 VOLUME 41 NUMBER 3 JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY duced due to the contact surface not be ing controlled In consultation with colleagues we found support for a simple low cost de vice to provide feedback on forces applied during manual therapy techniques to be used as a teaching tool Therefore we set out to develop a device that would mea sure display and store forces applied at a single point to the cervical spine in the performance of manual therapy tech niques The device had to be affordable and allow the user to perform most tech niques with minimal restriction With regard to its intended use as a means of providing feedback to students we con sidered it reasonable to sacrifice some accuracy for lower cost and greater ease of use The design criteria of the device were that it should 1 be simple to use and cal ibrate 2 cost less than 100 US
24. or your computer Change the appearance of desktop such as the background screen saver colors font sizes and screen resolution Folder Options Customize the display of files and folders change file associations and make network fies available offine Fonts Add change and manage fonts on computer Game Controters Add remove and configure game controler hardware such as joysticks and gamepads yinternet Options Configure your Internet display and connection settings Java Java TM Control Panel Keyboard Customize your keyboard settings such as the cursor bink rate and the character repeat rate R Customize your mouse settings such as the button configuration double cick speed mouse pointers and motion speed Network Connections Connects to other computers networks and the Internet TOM Configuration Controls PHANTOM hardware par e Phone and Modem Options Configure your telephone nuses and modem settings 5 Configure energy saving settings for your D Printers and Faxes Shows printers and fax printers and helps you add new ones Download Monitor Mai of Ce ration Scanners and Cameras Add remove and configure scanners and cameras EI Scheduled Tasks Schedule computer tasks to run Security Center View your current securty status and access important settings AudioESP SoundMAX AudioESP Change the sound scheme for your computer jure the settings for your speakers and recording devices to speech and for speech f
25. r areas 2 electronic circuitry to improve the linearity and range of response 3 more sophisticated analogue to digital con verters for simultaneously monitoring multiple channels or to achieve greater resolution and faster sampling rates and 4 wireless interfaces Positive feedback has been received on the device from both staff and stu dents of undergraduate and postgradu ate programs as well as students after short continuing education courses Us ing the sensors to measure applied forces before and after 2 continuing education courses therapists reduced the average force they applied during motion palpa tion by approximately 50 Preliminary feedback from clinical educators post graduate students and undergraduate students is that the device has been valu able in assisting students to more accu rately modulate forces applied during assessment and treatment techniques There is further research needed to de termine the effectiveness of this device in assisting students to produce consistent forces and in maintaining force applica tion skills over a period of months We are also investigating the repeatability of assessing pressure pain thresholds using the device as well as variations of the de vice using bare FSR sensors and or more sophisticated electronic interfaces CONCLUSION HIS TECHNICAL NOTE DESCRIBES A simple low cost device that fulfils the design criteria for providing feedback while teaching p
26. ressed zipped Folder 15 12 2010 3 05 PM E my Documents E My Computer Fie Edit View Favorites Toos Help GQ peck O iF seah gt rokers FX 19 Gy Packed S Hasa ___Sze _Ratio 184KB No 456KB 60 15 12 2010 2 51 PM 3 799 KB No 4 002 6 15 12 2010 2 51 PM License Agreement Please take a momentto read the license agreement now If you accept the terms below click I Agree then Next Otherwise click Cancel Pressure Sensor Via Sound Card is a program able to receive data from the Force sensor resistor via the computer s sound card Copyright C 2010 N Tuttle and G Jacuinde This program is free software you can redistribute it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation either version 3 of the License or any later version This program is distributed in the hove that it will be useful but 7 C IDo Not Agree Agree wa ceo ie ii Setup1 5 x N To install in this folder click Next To install to a different folder enter it below or click Browse Select Installation Folder The installer will install Setup1 to the following folder Eolder C Program Files Griffith University Setup1 Browse Disk Cost Install Setup1 for yourself or for anyone who uses this computer C Everyone Justme wo a E i Setup1 Confirm Installation Eh
27. udes of applied forces FIGURE 4 shows examples of how the device can be used while performing several techniques on the cervical spine If necessary the device can be held in place by double sided tape either on the therapist s hand or on the person being palpated Note that tape should not be placed over the top of the sensor as this will result in inaccurate readings Test of Accuracy After calibration as a vertical load known weights of 0 5 to 4 5 kg were ap plied at 0 5 kg intervals 3 times each using 4 different sensors on each of 3 dif ferent computers To assess the accuracy of the device Bland Altman plots were constructed for the mean differences be tween the actual values and those mea sured with the device across the 4 sensors and 3 computers The 95 limits of agreement the range within which 95 of the measures would fall were calculat ed in Newtons and percentage values To assess the repeatability of the device the repeatability coefficient was calculated and plots were constructed for the dif ferences between the repeated measures when using the same computer and sen sor The repeatability coefficient is similar to the limits of agreement except that it indicates how closely the repeated mea sures agree with each other rather than with a known value For example limits of agreement are relevant when a student intends to reproduce a force used by the instructor rather than a force of known
28. utting stripping and taping wires the use of a screwdriver and glu ing a washer to the sensor Alternatively the device can be hardwired and built ac cording to the wiring diagram presented in FIGURE 2 An installable version of the software is available online at www jospt org Calibration The sensor should be conditioned and calibrated prior to each session Condi tioning is accomplished by applying an JOURNAL OF ORTHOPAEDIC amp SPORTS PHYSICAL THERAPY VOLUME 41 NUMBER 3 MARCH 2011 175 FIGURE 4 Use of the device A The device in relation to a finger with the rounded bumper facing the finger B D The use of the device during 3 techniques to the cervical spine with an arrow indicating the location of the sensor approximately 5 kg load to the sensor 5 times for about 5 seconds each time Calibration consists of a 1 point proce dure using a mass of approximately 4 kg A full 4 liter or 1 gallon plastic bottle of milk or soft drink balanced upside down on the sensor can be used as a calibration mass producing approximately 39 5 and 37 5 N of force respectively including the weight of the bottle The volume control of the computer is then adjusted until the digital readout corresponds with the ap plied load Use The device is placed against a surface such as a desk or padded treatment ta ble and force is applied with a thumb or finger to assist students in gaining an ap preciation of the magnit
29. ver are expensive complex and or preclude their performance in a clinically relevant manner METHODS The design of the device was as sessed in accordance of the following criteria 1 ease of use 2 low cost 3 minimal interference with technique 4 ability to provide feedback with suitable accuracy at forces up to 50 N and 5 no requirement of specialized skills to construct RESULTS A device is described that interfaces with standard computers through the sound card and measures force using thin low cost force sensing resistors Evaluated against the design criteria the device 1 is easy to set up and use 2 can be produced for under 30 US dollars 3 creates minimal interference with performance of a variety of techniques 4 has limits of agreement from 3 8 to 4 2 N for forces of 5 to 45 N and repeatability coefficients of 2 0 N or 12 and 5 can be constructed without specialized skills or knowledge CONCLUSION A device is described that fulfils most of the design criteria for providing feedback on forces for physical therapy students and may have applications in other fields J Orthop Sports Phys Ther 2011 41 3 1 4 179 Epub 5 January 2011 doi 10 2519 jospt 2011 3461 KEY WORDS education force feedback manual therapy Ch force transmitted through the pa tient to the treatment table 579 or with the therapist on a force plat form the reduction of ground re action force un
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