Home

NeXus-10

1. 33 Version 1 32 NeXus 10 manual The Blood Volume Pulse Sensor NX BVP1A The NeXus 10 BVP finger sensor measures relative blood flow using optical electronics that measure near infrared light During each heart beat blood flows through the arteries and blood vessels At the peak of blood flow the BVP signal peaks as well The height of the peaks indicate the relative bloodflow which correlates with the level of vasodilation vasoconstriction at that point The distance between the peaks can be used to obtain the absolute heart rate HR or interbeat interval IBI The BVP signal is usually sampled at frequencies of up to 128 SPS If greater precision in HR or IBI is required for instance for research purposes we advise using an HR computed from an ECG signal which can be sampled at up to 2048 SPS Samples per second For clinical applications the BVP sensor usually is sufficient and usually more comfortable since it can be worn on the fingers Note however that the BVP sensor Is sensitive to movement artifact Movement and gravity may impact the BVP signal Therefore we advise that during a session the subject sit comfortably and still On the next page two examples of BVP signals are shown 6 34 Version 1 32 NeXus 10 manual Below a typical BVP signal is shown with no artifacts and a strong pulse The pulse amplitude shown below 16 about 200 millivolts mV I JL 500 0 550 0 00 0 F
2. Black 2 Negative Black 1 Figure 15 SCP electrode placement For ground reference we advise that the NX Ref1 SCP cable be used This is also a sintered electrode and may be placed anywhere on the face or in the neck shoulder area Sintered electrodes provide a greater DC stability and therefore are more suitable for SCP recordings Before each use please prepare the skin carefully with alcohol skin prep NuPrep and EEG paste 10 20 It usually takes some time before the electrodes are stabilized so we advise you to wait 5 10 minutes before you start the actual SCP recording After use gently clean the electrodes with warm water and tippex to remove the EEG Paste from the electrode cups This cable can be used to measure SCP and the EEG simultaneously 6 28 Version 1 32 NeXus 10 manual The dual channel EEG Cable NX EEG2 This bi polar cable uses standard 10 mm EEG cup electrodes with silver silverchloride coating It has two negative cups labeled black and two positive cups labeled red The cups labeled with the number 1 are used for channel A or channel C red1 black1 The cups labeled with the number 2 are used for channel B or channel D red2 black2 Figure 16 EEG electrode cable Please note that this cable is bi polar and it can be used for 1 channel of EEG or for 2 channels of EEG In both cases a ground reference cable must be placed on the body The ground cable may in this case also
3. FRONTAL CENTRAL EAR PARIETAL OCCIPITAL Figure 8 the 10 20 Electrode System 6 20 Version 1 32 NeXus 10 manual For 1 or 2 channel Neurofeedback C3 and C4 are also often used With NeXus 10 you can record up to 4 channels of EEG Recording EEG signals with the NX EXG2 Snap cable NeXus 10 requires snap on EEG electrodes In this case the 2RT3 electrodes were used Before applying these electrodes the skin should be prepared with skin prep and electrode paste Please refer to professional publications and literature on EEG and neurofeedback for more information on the 10 20 system skin preparation and electrode locations Please contact your NeXus 10 reseller for information on these or compatible electrodes skin preparation and electrode paste products C Ess 21 Version 1 32 NeXus 10 manual A sample surface EMG signal With the same NX1 EXG2 Snap cable you can record surface EMG signals In that case you will also need to place a positive negative and ground electrode on the body A sample of a single channel EMG signal is shown below during relaxation and during contraction The range shown is 500 microvolt pk pk A digital EMG bandpass filter was set to 20 500HZz in the PC software E 100 0 This signal was measured on the masseter jaw muscle using a triple pregelled electrode e e This electrode offers standard 20 mm distances between the electrode and is
4. Not to be immersed in any liquid If any liquids or moisture penetrate the system or any part thereof remove the batteries from NeXus 10 and have the system checked by an approved technician Take care in arranging patient and sensor cables to avoid risk of patient entanglement or strangulation When the distance between the Bluetooth PC receiver and the NeXus 10 is more then 10 meters or when there are conducting materials in the Straight line between the Bluetooth PC receiver and the NeXus 10 signal quality cannot be guaranteed Do not use an operating cellular phone within 30 cm of the NeXus 10 to avoid excessive noise on the signals Not to be connected to a patient undergoing MRI Electro surgery or defibrillation Not for critical patient monitoring Not defibrillator proof Sharp bends or winding the cables in a loop smaller than 5 cm may damage the cables Dispose of batteries according to local regulations The NeXus 10 contains recyclable materials that can be harmful for the environment Specialized companies can separate these materials when the apparatus is disassembled Before disposing of the apparatus enquire about the local waste management regulations 6 8 Version 1 32 NeXus 10 manual Caution e When the NeXus 10 is not in use for more than a week the batteries have to be removed to prevent damage in case they start leaking e Except for the batteries there are no user serviceable parts within the NeXus 10
5. Red electrode and ground electrode can also be placed on the left wrist and the negative Black electrode on the right wrist This placement will pick up EMG artifact A sample of such an ECG with wrist placement is shown below l E 200 0 200 0 100 0 pee Tl ogy 00 422 0043 Notice that the range of the ECG signal now is smaller in this case 400 microvolts peak to peak and that the signal looks much noisier The noise in this example is EMG activity that is picked up by the same electrodes When the EMG noise becomes too strong the R peak may no longer be visible and the heart rate HR may in such a case not be computed correctly by the PC software To reduce EMG artifact the subject should relax arm and chest muscles Ground t white Neg Black N Figure 12 ECG wrist placement front view A sample EOG DC signal Ess 25 Version 1 32 NeXus 10 manual The same NX1 EXG2 Snap cable may be used to measure the EOG electro oculogram which is a DC signal that shows the electrical activity when the eyeball moves The EOG can be measured ina horizontal fashion for detection of eyeball movements from left to right In the sample below the EOG was measured vertically Eyeball movement Up and Down Notice the negative DC offset about 8000 microvolts E Eyes looking Up 7500 0 7750 0 8000 0 This short 2 second trace shows the eyeball in neutral position then looking u
6. User Manual for the NeXus 10 Manufactured in Europe Worldwide distributor Mind Media B V schepersweg 2B NL 6049CV ROERMOND HERTEN WWW MINDMEDIA NL Email info mindmedia nl Tel 31 0475 410123 Fax 31 475 330602 Distributed in the USA by Stens Corporation 3020 Kerner Blvd Suite D San Rafael CA 94901 5444 Phone 800 257 8367 415 455 0111 Fax 415 455 0333 Email sales stens biofeedback com Web www stens biofeedback com NeXus 10 manual 6 Version 1 32 June 2005 Code 92 0298 001 0 1 32 6 2 Version 1 32 Contents 1 2 FA ANA ADA A A CW INTRODUCTION PRODUCT DESCRIPTION INTENDED USE PRODUCT LIABILITY LIMITATION OF LIABILITY ABOUT THIS MANUAL PRECAUTIONARY MEASURES WARNINGS amp CAUTIONS Warnings Caution CONTENTS OF THE PACKAGING IDENTIFICATION OF IMPORTANT PARTS INSTALLATION OPERATING INSTRUCTIONS TECHNICAL BACKGROUND MAINTENANCE TROUBLE SHOOTING The light does not go on when switching on the NeXus 10 The light stays orange No Bluetooth connection possible Bad signal no signal on channels with electrodes Recording error on SD Orange blink 10 SPECIFICATIONS 3 NeXus 10 manual ONnNANAN N DANS A gt N m Aa a N Ja p KK KR KR A KROQ RON NON aN Ua Version 1 32 NeXus 10 manual 1 Introduction Product description The NeXus 10 is a 10 channel physiological monitoring and biofeedback pl
7. NeXus 10 This will result in the light going off In some situations the NeXus 10 will not switch off by pressing the button 1 When a PC connection is active or when an ambulatory recording is active the latter is indicated by a blinking green light You will first have to stop the session on the PC or stop the ambulatory recording The ambulatory session can be stopped by pressing down the button for 4 seconds or longer 2 When the battery cover is removed the NeXus 10 will always switch off regardless of its status Note that this can result in undesired effects so always switch the NeXus 10 off before removing the battery cover Attaching connectors The connectors are protected against wrong entry so make sure the red dot on top of the connector is positioned directly across from the red dot on the connector in the NeXus 10 Do not apply too much force the need for force indicates wrong alignment so check this first Using Patient electrode leads Always use one unipolar shielded cable Snap connector or fixed Ag AgCl electrode cup for patient ground Gnd connection Connect the electrodes for physiological measurements to input A B C or D For a good recording make sure the electrodes make good contact with the patient The patient ground electrode is especially important in this case Using other sensors Connect the sensor to one of the auxiliary inputs E F G or H 6 15 Version 1 32 NeXus 10 manual Using th
8. Repairs can only be performed by the manufacturer e The design of the NeXus 10 is such that no calibrations are needed e There are no known side effects from the use of this equipment 6 9 Version 1 32 NeXus 10 manual 3 Contents of the packaging Standard contents NeXus 10 package NX10EH 95 0928 0 0 NeXus 10 95 0007 001 Bluetooth USB module MSI or LinkSys 75 0924 001 Suitcase for the device and optional accessories 07 1000 100 Leather carrying case Optional accessories NX EXG2 Snap 2 channel EEG EMG EKG EQG sensor cable NX REF1 Snap EEG EMG EKG EQOG ground reference cable NX EEG2 2 channel EEG sensor cable NX REF1 EEG EEG ground reference cable NX SCP1A 2 channel SCP sensor cable NX REF1 SCP SCP ground reference cable NX TMP1A skin temperature sensor NX AUX1A Skin Potential sensor NX GSR1A SC GSR sensor NX BVP1A Blood Volume Pulse sensor NX RSP1A Respiration sensor 95 200 15 Finger electrodes for SC GSR sensor NX SPO2 Nonin Oximetry finger Sensor 6 10 Version 1 32 NeXus 10 manual 4 Identification of important parts a as D2 Mare fy Hi On Off Button Bluetooth USB interface Indication Light Patient ground connector Bipolar inputs A B C amp D Auxiliary inputs E F G amp H Battery compartment MultiMedia card slot Nonin Oximetry and Trigger input 0 Battery cover OONDOOFWND gt C Ess 11 Version 1 32 NeXus 10 manual 5 Installation Install th
9. be the snap on cable Type NX EXG Ref1 Snap An example of a single bi polar channel use would be to place the ground reference cable on one of the mastoids the positive cup red 1 on the C3 and the negative cup black 1 on C4 The other two electrodes red2 black2 would not be used See fig 17 on the next page An example of a dual channel bi polar montage would be C3 F3 channel 1 and C4 F4 channel 2 See fig 18 on the next page Please note that the in the EEG literature many different electrode placements are published most of which are supported by this cable 6 29 Version 1 32 NeXus 10 manual NASION Negative Positive Black 1 Red 1 Ground Ref On Ear or Mastoid Figure 17 single channel bi polar placement example NASION Negative Black 2 Negative Black 1 Channel 2 Channel 1 Right Left A2 Ground Ref Positive Positive Red 1 Red 2 INION Figure 18 dual channel bi polar placement example 6 30 Version 1 32 CE NeXus 10 manual The SC GSR Sensor NX GSR1A The NeXus 10 skin conductance sensor or GSR for galvanic skin response measures the sweat gland activity which is a sensitive indicator of arousal Skin conductance is expressed in micro mho or micro siemens and increases when the arousal level increases During relaxation the SC level normally decreases Because of the NeXus 10 ultra high 24 bit resolution changes of up to 0 001
10. micro mho can be detected in the range from 0 1 to 1000 micro mho N G Figure 19 Skin Conductance Sensor This sensor requires Ag AgCl finger electrodes that snap into the two connectors Polarity of the electrodes is not important The sensor is designed to measure minute relative changes in skin conductance A sample of the placement of the finger electrodes is shown on the next page 31 Version 1 32 NeXus 10 manual The signal below shows a sample skin conductance signal during relaxation At 00 07 there is a temporary increase of the SC signal the general trend however is downwards I FI 6 20 6 00 5 00 5 60 00 ggo ggg 00 06 ggg gpg 10 oo p014 oo 16 Figure 20 Example of SC signal 6 32 Version 1 32 NeXus 10 manual The Skin Temperature Sensor NX TMP1A The NeXus 10 temperature sensor supports very high resolution temperature reading from the skin It measures relative changes of up to 1 1000 degree Fahrenheit or Celsius in the range from 10 40 C 50 104 F Skin temperature is often measured on the fingertips and changes rather slowly The sensor can best be placed on the finger using medical self adhesive tape In the sample below the temperature changes less than 0 01 degrees Fahrenheit over 15 seconds E 97 575 97 550 97 525 gg 3g gag gg gg l gg gg g gg ga 4g 04 50 0 52 g ia Figure 21 Example of a temperature signal Fahrenheit
11. pre gelled so it has improved skin contact For wide EMG placements single surface electrodes may also be used 6 22 Version 1 32 NeXus 10 manual AA D fea PD fea SA Ground Ref JE aJ White JE Figure 9 Triple Gel electrode on Masseter Negative Black Positive Red Ground White Figure 10 Wide placement on Upper Trapezius For wide placements of EMG electrodes single electrodes should be used Please contact your reseller for more information on these or compatible EMG electrodes We advise you to use pre gelled electrodes 6 23 Version 1 32 NeXus 10 manual A sample ECG EKG signal The NX1 EXG2 Snap cable also enables heart rate detection through ECG signals A sample signal of an ECG signal on input B is shown below Notice that the R peak of the QRS complex should be pointing upwards for the HR detection in the PC software to work correctly E 14000 0 123000 0 12000 04 11000 04 pt TIL 00102 00103 ooo In this case the signal is displayed in a range of 3000 microvolts peak to peak and has a DC offset of 12000 microvolts This signal was obtained from a vertical electrode position as shown below also called Lead II Ground Ref white Negative Black Positive Red Figure 11 ECG Lead II Chest Placement C Ess 24 Version 1 32 NeXus 10 manual When a chest placement is not possible or not desirable the positive
12. 1 General requirements for safety EC 60601 1 2 2001 Medical electrical equipment Part 1 2 Electromagnetic compatibility safety class according to IEC 60601 1 internally powered type CF Dimensions 11 4 x 9 8 x 3 7 cm I x b x d Weight 234 gram Internal power supply Batteries 2 x AA type rechargeable NiCad or NiMH 1 2V or disposable alkaline 1 5V Battery low indication level 2 1V 0 1V Battery empty shut down level 1 9V 0 1V Duration on average 10 20 hours depending on sensor configuration Bipolar inputs EEG ECG EOG EMG etc Typical noise level lt 0 8 uV rms 256 SPS EEG Range 1 45Hz Gain 19 5 x Input signal difference lt 0 1V Input common mode range 2V 2V Inout impedance gt 10 Q CMRR 100 dB Connector LEMO 6 pin Accuracy 2 C Eass 43 Version 1 32 AUX inputs Gain Input signal range diff Input common mode range Input impedance CMRR Output voltage Connector Accuracy Sampling Resolution Bluetooth communication Bluetooth 1 1 class 2 Used profile Line of sight range C Geos NeXus 10 manual 1x 2V 2V 2V 2V gt 10 Q 80 dB 5V 5V max 5mA per channel LEMO 5 pin 2 24 bits Bipolar 12 2 nV per bit AUX 0 238 uV per bit Sample frequency Fs Bipolar 2048 Hz Aux 128 Hz amp Bluetooth Serial port profile 10 meter 44 Version 1 32 NeXus 10 manual NeXus 10 is exclusively manufactured for Mind Media by TMS In
13. aced simultaneously and all have to be of the same type Note the orientation of the batteries It is advised to place fresh batteries before each use to make sure the system operates long enough e When using rechargeable batteries always charge according to instructions of the battery manufacturer e This system is not suitable for use in an inflammable mixture of anesthetics and air oxygen or nitrous oxide e This system is not suitable for sterilization e Do not use aggressive chemicals to clean the system e Do not expose the system to direct sunlight heat from a source of thermal radiation excessive amounts of dust moisture vibrations or mechanical shocks 6 7 Version 1 32 NeXus 10 manual The NeXus 10 is totally isolated from the mains 110 220V due to battery operations but make sure the PC is installed according to local regulations and safety precautions Disposable electrodes which are used for EMG measurement etc may be a biohazard Handle and when applicable dispose of these materials in accordance with accepted medical practice and any applicable local State and federal laws and regulations Reusable electrodes present a potential risk of cross infection especially when used on abraded skin unless they are restricted to a single patient or sterilized between patients When sterilizing electrodes employ only gas sterilization Store electrodes within separate bag within the packaging to prevent contamination
14. atform that utilizes Bluetooth 1 1 class 2 wireless communication and flash memory technologies NeXus 10 offers data acquisition at up to 2048 samples per second The advanced technology preamps enjoy independent 24 bit A D converters per channel with DC coupled amplifiers allowing DC to 800 Hz 4dB recording including EEG ECG EMG EOG true DC and slow cortical potentials Because this system uses carbon cables with active shielding movement and noise levels are very low by design Figure 1 NeXus 10 The first four channels operate at a sample frequency of 2048 Hz and can be used for EEG EMG ECG EOG and SCP Slow cortical potentials measurements The second four channels operate at a sample frequency of 128 Hz and can be used for RSP BVP SC EDR Skin Potentials and Skin Temperature measurements The remaining two channels are available for SpO2 oximetry and or pulse or event synchronization 6 4 Version 1 32 NeXus 10 manual ee Intended use The NeXus 10 is a battery powered biofeedback device intended to monitor and feed back physiological parameters on the human body for relaxation training muscle reeducation and prescription use Please note the system is NOT intended for use in a life supporting system or for vital monitoring For USA based customers end users The NeXus 10 Biofeedback Units are available BY PRESCRIPTION ONLY Please consult with your clinician to find out if they are appropriate for your in
15. dividual situation 6 5 Version 1 32 NeXus 10 manual Product liability Limitation of liability Insofar as is maximally permitted under the applicable prescriptive law neither Mind Media nor its suppliers or dealers are liable under any circumstances for any indirect exceptional incidental or consequential damages arising from the use of the product or from the inability to use it including but not restricted to the damage arising from loss of goodwill work interruption computer defects or faults or any other damage or losses consequential upon business interruption even if the possibility of these occurring had been mentioned and irrespective of the legal or impartial theory agreement unlawful act or otherwise on which the losses are based In any case and pursuant to any of the provisions of the present agreement the total liability of Mind Media is limited in its entirety to the sum of the price that was paid for this product and the fee for the product support granted by Mind Media under a possible separate support contract with the exception of death or personal injury arising from negligence by Mind Media insofar as the applicable prescriptive law forbids limitation of damages in such cases Mind Media cannot be held liable tor the consequences of any incorrect information furnished by its staff or for any errors in this user guide and or other accompanying documentation including trade documentation The ot
16. e Bluetooth interface according to the PC software manual Install the PC software according to the PC software manual Remove the battery cover from the NeXus 10 by pressing the marked area on the bottom of the cover while sliding the cover backwards Figure 2 Opening battery cover NeXus 10 Place the two batteries according to the details shown inside the battery area and close the cover again Make sure that no patient is attached to the NeXus 10 when replacing batteries C Ess 12 Version 1 32 NeXus 10 manual 20 E Ta Figure 3 Battery placement NeXus 10 The NeXus 10 will not operate when the battery cover is not closed Press the button on top of the NeXus 10 and check the light in the front When the light shows orange followed by a green light the NeXus 10 is operational Figure 4 Front of switched on NeXus 10 When the light does not turn on check the batteries and the battery cover When the light stays orange the NeXus 10 is not functioning correctly see chapter 10 for details on what to do next 6 13 Version 1 32 NeXus 10 manual Follow the directions in the software manual to install the BlueTooth drivers These are supplied with the PC software After installation of the BlueTooth environment search for new BlueTooth devices and add the device to the list When connecting the NeXus 10 to the PC for the first time you will be asked for a passkey sometimes also called a pinc
17. e pulse oximeter optional Apply the sensor to the patient as indicated by the Nonin instruction manual Connect the sensor to the XPOD module Connect the XPOD module to the Nonin trigger connection The red light in the sensor should be visible Using the On Off button as a Marker button The button can be pressed during connection with the PC software and ambulatory measurements to record special moments or situations Note that pressing the button for more than 4 seconds will start stop the ambulatory recording Recording signals There are 2 main ways to use the NeXus 10 stationary and ambulatory Stationary use In stationary use the signals that are measured by the NeXus 10 are sent to the PC by Bluetooth and processed and or recorded by the PC software Ambulatory use In ambulatory use the signals that are measured by the NeXus 10 are sent to a prepared flash card Secure Digital format that is placed inside the NeXus 10 First the PC software 16 required to initialize the flash card see the PC software manual for more details Then place the initialized flash card into the NeXus 10 Switch off the NeXus 10 and open the battery cover Then place the flash card with the label of the card towards the top of the NeXus 10 and press to enable the reader lock To remove the flash card press again to release the card Then connect all desired sensors and start up the NeXus 10 as described above Then press the ON OFF butto
18. el RSP sensor positioned on the chest RSP Sensor positioned on the abdomen E 1650 0 1600 0 Figure 24 Example of an abdominal respiration curve 6 37 Version 1 32 NeXus 10 manual 8 Technical background In the NeXus 10 the following items can be found connectors analog inputs A D for electroohysiological signals m connectors analog inputs E H for auxiliary signals Real Time Clock RTC Battery compartment Bluetooth serial connection Auxiliary input stage Each auxiliary input has a 5 pin connector Signals on this connector are 5V output 5V output GND signal input and signal input The 5V 5V GND pins are used to power an active sensor The and inputs are connected to an instrumentation amplifier with a gain of 1 An unconnected input will automatically be switched off i e will show a zero signal without noise The output of the amplifier goes to the ADCs without any filtering Real Time Clock RTC The RTC continuously keeps time even if no batteries or external power are connected The RTC uses its own button cell battery for power backup Lifetime of this button cell is at least 5 years Batteries Batteries are used as the power source for the NeXus 10 The NeXus 10 can work with both rechargeable and disposable batteries Maximum operating time depends strongly on the type of battery chosen Rechargeable batteries have both lower voltage as well as lower capacity mA
19. es is usually indicated on the battery itself 6 39 Version 1 32 NeXus 10 manual 9 Maintenance There are no user serviceable parts within the NeXus 10 Maintenance is limited to regular cleaning Cleaning of the NeXus 10 can be done with a slightly damp soft cloth Before cleaning make sure the NeXus 10 is turned off and not in contact with a patient 6 40 Version 1 32 NeXus 10 manual 10 Trouble shooting The light does not go on when switching on the NeXus 10 The most likely reason is that there is no power available from the batteries Make sure the batteries are charged and that the battery cover is undamaged and closed correctly The light stays orange This indicates that the NeXus 10 is unable to start up correctly First check the batteries If the problem still occurs send the NeXus 10 back for repair No Bluetooth connection possible Make sure the distance between the NeXus 10 and the Bluetooth interface is less then 10 meters When possible check the working of the Bluetooth interface with another Bluetooth device If it still does not work contact your supplier Sometimes it is necessary to remove and then again add the NeXus 10 device to your BlueTooth Windows environment so that it will be found again In that case you would use the Remove and Add buttons as shown in the picture below actual screen display may vary Bluetooth Devices Devices Options COM Ports Hardware All other d
20. evices NeXus 10 0928040019 Passkey enabled Remove Properties Under COM ports settings should preferably be between COM3 COMS9 C oss 41 Version 1 32 NeXus 10 manual Bad signal no signal on channels with electrodes Replace the electrodes on the skin of the patient If this does not work move the cable and check if this results in occasional signals on the PC If this happens the cable is broken and has to be replaced If it is still not working replace the cable with another cable and recheck If it is working use the new cable and dispose of the old cable If it still does not work check the working of the NeXus 10 with any available sensor or electrode If the NeXus 10 is not working send it for repair Otherwise replace non working cables Recording error on Flash Memory Light blinks orange Possible courses for this are e No valid Flash card Secure digital SD e The Flash card was not formatted correctly e The Flash card is missing the Flash initialization files e he Flash card is full C Ess 42 Version 1 32 NeXus 10 manual 11 Specifications NeXus 10 C Es This apparatus meets all the requirements of the Medical Device Directive 93 42 EEC Classification of medical device For Europe lla rule 10 For the USA Class 11 medical device 510K exempt FDA Sec 882 5050 Biofeedback Device Safety conforms to IEC 60601 1 1988 A1 1991 A2 1995 Medical electrical equipment Part
21. h Therefore the measurement time is lower than when Alkaline batteries are used The power consumption increases when more auxiliary sensors are added The measuring time will then decrease When good alkaline batteries for instance Duracell MN1500 are used on average the duration of battery power should be at least 10 hours when only the EXG sensors inputs A D are used 6 38 Version 1 32 NeXus 10 manual When batteries are changed make sure that all batteries are replaced at the same time Battery check the NeXus 10 monitors the voltage of the batteries Two thresholds are present The first ca 2 1 V 16 the battery low threshold If the total battery voltage comes under this level the orange light will start to blink At this point you may still have more than 30 minutes of battery life left but we advise you to stop the recording and replace the batteries lf the batteries are not replaced the battery voltage will eventually drop below the battery empty level ca 1 9 V Up to this point operation of the NeXus 10 is still normal When the bat empty level is passed the NeXus 10 will close the measurement file and shut itself down in an orderly fashion TIP in case you decide to use rechargeable batteries do NOT use NiCad batteries their capacity is too low Rather we advise you to use NIMH batteries with a capacity of at least 2200 mAh milli amp re hours The capacity of the rechargeable batteri
22. her party the user of the product of his or her representative must hold Mind Media harmless and indemnify it against any third party damages irrespective of their nature and irrespective of the relationship with the other party 6 6 Version 1 32 NeXus 10 manual 2 About this manual This manual which 16 intended for the user of the NeXus 10 contains general operating instructions precautionary measures maintenance instructions and information about components To maximize the safety service life and efficiency of the system it is important that you read this manual through carefully and familiarize yourself with the various controls and accessories before starting to use the system Precautionary measures This section contains general warnings and precautionary measures that are important for the safe use of the system AN manual contains important safety information M internally powered type CF Warnings amp cautions Warnings e Transport the NeXus 10 in its original case e See manual of the PC software for details about the PC specifications e Only use sensors and electrodes as described within this manual and specified by Mind Media e Do not combine the use of the NeXus 10 with any other electronic device except those specified in this manual e Before batteries are replaced disconnect the patient from the NeXus 10 Make sure that the NeXus 10 is switched off light is off All batteries have to be repl
23. igure 22 Example of a clean BVP signal The next picture shows a rather weak signal 10 mV amplitude containing movement artifact from 00 29 to 00 31 During such artifacts the heart rate HR usually cannot be computed correctly Preferably a BVP sensor should output at least 10 mV in order for the Signal to clear enough to measure HR and vasoconstriction levels J E aso nwo 2250 30 0 Figure 23 Example of BVP signal with artifact 35 Version 1 32 NeXus 10 manual The Respiration Sensor NX RSP1A The NeXus 10 respiration sensor measures the relative expansion of the abdomen or thorax during inhalation and exhalation It consists of an elastic belt that is worn around the body and a sensor part shown below The elastic belt comes in two sizes small and large The sensor can be worn on top of a shirt or sweater For best results we advise that there be only 1 or 2 layers of clothing between the sensor and the skin When recording the respiration activity the elastic belt always remain under some tension such that even during full exhalation the belt still won t be loose Since it measures relative movement the sensor does not need to be calibrated 6 36 Version 1 32 NeXus 10 manual In the picture below the positioning of the respiration sensor is shown on the thorax and on the abdomen When used on the abdomen the sensor part normally is placed around the position of the nav
24. n for more than 4 seconds The green light will Start blinking indicating that recording on the flash card is busy or if an error situation is present the light will blink orange to indicate this The recording can be stopped by pressing the ON OFF button again for more than 4 seconds After shutting down the NeXus 10 the flash card with the recorded signals can be read by a flash card reader on the PC for further processing C 6 16 Version 1 32 NeXus 10 manual 7 NeXus 10 Sensors The electrophysiological Sensors Inputs A B C and D acquire electrophysiological signals through the advanced DC instrumentation amplifiers that are built into the NeXus 10 Because of this design expensive active amplifiers are no longer required for each electrophysiological modality The DC instrumentation amplifiers amplify the difference between a plus and minus signal The patient ground reference electrode is required to keep patient potential and NeXus 10 potential at about the same level When using the inputs A D the ground reference electrode must always be used Its location on the body is not critical and depends on the application For EEG the ground reference is often put on the ear or elsewhere on the head Since the input impedance of the active channels is very high 10 Q the influence of electrode impedance is very small It should not be necessary to perform electrode impedance measurements Instead the NeXus 10 offe
25. ode This passkey consists of the last 4 digits of the serial number of your NeXus 10 This serial number will be listed by Windows and can also be found at the bottom of the NeXus 10 encoder 17 NeXus 10 SN 0928050124 Power 2xAA batt 0 5W CEs IA J Bluetooth REF 95 0928 008 0 7 Figure 5 Serial Number of NeXus 10 In the picture shown above the serial number is 0928050124 Thus the BlueTooth passkey would be 0124 In your case the passkey will be different but will still consist of the last 4 digits After installation of the NeXus 10 device Windows will designate 2 serial COM ports for the digital communication to your personal computer The Passkey normally has to be entered only once unless you connect your NeXus 10 or USB dongle to another computer In that case you need to re connect and thus re enter the passkey After entering the passkey you are ready to use your PC Software with NeXus 10 Please refer to the PC software manual for instruction on connecting and re connecting the NeXus 10 to the Windows BlueTooth environment C Ess 14 Version 1 32 NeXus 10 manual 6 Operating instructions Switching the NeXus 10 on The NeXus 10 can be switched on by briefly pressing the button on top of the NeXus 10 When the light goes from orange to green the NeXus 10 is ready for operation Switching the NeXus 10 off The NeXus 10 can be switched off by briefly pressing the button on top of the
26. p and then looking down and going back to neutral Standard single pre gelled electrodes were used Positive Red electrode Negative Black Figure 13 Vertical EOG placement 6 26 Version 1 32 NeXus 10 manual NX SCP1A sample SCP DC signal The NeXus 10 can record EEG and SCP signals simultaneously or in other words it can record signals between DC OHz and 40 100 Hz for EEG The SCP signal is usually averaged over a certain window so only the slow DC changes will visible Below a sample of an SCP signal is shown HOE 11425 11400 11375 Notice how this SCP signal has a DC offset of about 11400 microvolts pk pk and notice that negative values are plotted upwards This is a polarity convention in neurophysiology In this sample the trend of the SCP is in the positive direction the signal moves downwards positivity Figure 14 NX SCP1A cable C Ess 27 Version 1 32 NeXus 10 manual For SCPs the NX SCP1A cable is used with the RED electrode on the Cz the Black 1 electrode on the left mastoid and the Black 2 electrode on the right mastoid This cable is essentially a dual channel cable and can be used for obtaining 2 channel EEG data from the same electrodes left mastoid Cz and right mastoid Cz as well The positive Red 62 electrode combines the positive electrodes of channel 1 amp 2 This SCP cable uses high quality sintered electrodes Positive Red on Cz Negative
27. rs electrode OFFSET checking even while recording data A poor electrode contact results in a high electrode offset If the offset becomes too high NeXus 10 will flatline the signal The PC software may warn you during a live recording when the offset of an input is too high All electrode cables are shielded with the average of the plus and minus electrode signal active shielding This ensures a measurement that is virtually free of movement artifact Mains 110 220V interference 50 60HZ is hereby also reduced to a minimum After the first amplifier stage the signals go directly to the ADC No high pass or low pass filters that can cause signal phase shifts or filter overflows are present All further digital processing takes place on your PC or notebook computer C Ess 17 Version 1 32 NeXus 10 manual The dual channel EXG Snapon Cable NX EXG2 Sna This cable provides 4 standard snap on connectors for two bi polar inputs It can be used for electrophysiological signals between DC and 800 Hz such as EEG surface EMG ECG and EOG Figure 6 NX EXG2 Snap cable Please note we do not advise that this cable be used for SCP signals For Slow cortical potentials the NX SCP1A cable should be used For each input channel there is a RED positive and BLACK negative snapon When the cable is used for input A amp B the red and black connectors marked with 1 will record data for input A The ones marked wi
28. ternational BV Office address H ter Kuilestraat 181 7547 SK Enschede The Netherlands Mail address P O Box 1123 7500 BC Enschede The Netherlands Environmental conditions for transport and storage 10 C 70 C 10 90 500 hPa 1060 hPa Environmental conditions for normal use 10 C 40 C ese 10 90 500 hPa 1060 hPa Please note the manufacturer reserves the right to make technical changes without prior notice 6 45 Version 1 32
29. th 2 will record data for input B If sensor inputs C amp D are used connectors marked 1 will record on C and 2 will record on D 6 18 Version 1 32 NeXus 10 manual Because a bi polar input always requires a ground electrode you will need the snap on ground reference electrode shown below Figure 7 NX EXG Ref1 Snap cable This cable has a snap on electrode on one end and a micro coax connector on the other end Please connect the micro coax connector to the input marked Gnd On the NeXus 10 In the pictures on the next pages samples of EEG ECG and EMG signals are shown all recorded with this cable But different types of electrodes and different locations on the body are used 6 19 Version 1 32 NeXus 10 manual A sample EEG signal In the picture below a sample EEG signal is shown containing a mixture of Alpha waves and low amplitude Beta waves Raw EEG signals in the range of 1 45Hz typically show amplitudes between 10 and 50 microvolts pk pk E 50 0 w AA A Af Murry A Nf AW N al 00 02 00 03 ggg In this case the EEG signal was recorded on Input A with the ground reference electrode on the right mastoid A2 the positive electrode red marked with 1 on the Cz location and the negative black marked with 1 on the left mastoid A1 The picture of the 10 20 system below shows these locations NASION PRE FRONTAL

NeXus-10

Contents

Download Pdf Manuals

Related Search

Related Contents