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PROTOCOLS FOR INVESTIGATING NEUROMUSCULAR SYSTEM FUNCTIONS

All the protocols described below use equipment that is specifically designed for use with human subjects. This includes computers (e.g. „Powerlabs‟) running data acquisition software of various kinds depending on the signals to be recorded, and stimulators that are isolated from the mains. Where electrical stimulation is required, stimulus durations are preset to be short, to avoid reaching threshold for nociceptive (pain) fibres.

Student handbooks include detailed protocols. Exclusions for individual practicals are specified in these handbooks, as well as described in the introduction to each practical.

Informed consent is required, and subjects have the right to withdraw from the experiment at any time.

Data collection is anonymised.

For investigation of balance, all students will be instructed in standard manual handling techniques, so that they know how to manage any falls safely.

Where subjects perform several experiments in one (2-4 hour) session, appropriate rest breaks must be allowed.

Practicals carried out at external sites are governed by regulations at those establishments, and approved by the local Research Ethics Committee. They are not listed here.

List of protocols page

1) Nerve conduction studies .................................................................................................................. 2 1.1) Non-invasive measurement of Motor conduction in peripheral nerves. ....................................... 2

1.1.1) Version 1 for Ulnar nerve motor conduction velocity: ........................................................... 2 1.1.2) Version 2 for the Median nerve motor conduction velocity: .................................................. 2

1.2) Non-invasive recording of a sensory nerve conduction velocity .................................................. 3 1.2.1) Version 1 for Ulnar nerve, orthodromic sensory conduction: ................................................ 4 1.2.2) Version 2 for Ulnar nerve, antidromic sensory conduction: .................................................. 4 1.2.3) Version 3 for Median nerve, orthodromic sensory conduction: ............................................ 5 1.2.4) Version 4 for Median nerve, antidromic sensory conduction: ............................................... 5

2) Muscle force regulation and motor unit „recruitment‟ investigations using EMG recordings ............... 6 2.1) Version 1: EMG and recruitment ............................................................................................... 6 2.2) Version 2: Grip force and EMG during an isometric contraction .................................................. 7

3) Determination of the isometric contractile properties of the triceps surae using percutaneous stimulation. ........................................................................................................................................ 8 4) Knee extensor muscle function muscle assessed using isokinetic dynamometry .............................. 8 5) An investigation of factors contributing to Muscle fatigue. ................................................................ 10 6) Reflexes .......................................................................................................................................... 11

6.1) Stretch reflex ............................................................................................................................ 11 6.2) Hoffman Reflex. ....................................................................................................................... 12

7) Reaction times. ............................................................................................................................... 13 8) Gait examined by means of footprint analysis (pedograph) system ................................................. 14 9) Tests of balance. ............................................................................................................................. 14

9.1) Romberg test ............................................................................................................................ 14 9.2) Star excursion balance test (SEBT) .......................................................................................... 15 9.3) Measurement of sway. ............................................................................................................. 16

9.3.1) Measurement of lateral sway, using a small laser pointer fixed to the standing subject. .... 16 9.3.2) Measurement of anterior-posterior sway using a wire Goniometer or optical Goniometer attached to the ankle. ........................................................................................................ 17 9.3.3) Measurement of lateral and anterior-posterior sway on a wobble (or sway) platform. ........ 17

9.4) Berg Balance test . ................................................................................................................... 17

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1) Nerve conduction studies

1.1) Non-invasive measurement of Motor conduction in peripheral nerves.

Electrical stimulating pulses applied percutaneously to the nerve at a position where it is quite superficial

will excite -motoneuron axons innervating muscles. The electrical response of this muscle (electromyogram; e.m.g.) can be recorded via a pair of recording electrodes placed on the skin overlying the muscle. The latency of the response (time elapsed between a given start point and a specific event following it) corresponds to the conduction time along the nerve plus a synaptic delay at the neuromuscular junction. Stimuli are applied at two different sites along the nerve and the latency of the e.m.g. response in both cases will be measured. The difference in response latencies obtained is therefore a measure of the time taken for the action potentials to travel along the nerve between the two stimulus points.

Used adhesive electrodes and any swabs used to clean the skin should be disposed of in the clinical waste bins as soon as you have finished with them.

1.1.1) Version 1 for Ulnar nerve motor conduction velocity:

The subject should sit in a chair with a back. Select the subject's non-dominant hand and fix the recording electrodes over the hypothenar eminence. Clean the skin first with the swab, and allow it to dry before attaching the adhesive recording electrodes to the skin. The recording electrodes should be placed over the muscle and the earth electrode either over the bone at the base of the little finger or over the back of the hand. Connect the electrodes to the recording leads using the crocodile clips. The green lead (or lead with a green & yellow tag) is the earth lead; it does not matter which way round the other two electrodes are connected. The other end of the recording leads should be connected to the Powerlab (or equivalent) computer used to make the recordings. Proceed as follows:

Step 1. Check the system is working and you can record EMG. Open up the „oscilloscope‟ recording mode (e.g. via clicking on the „NCV‟ icon), and start by setting the recording time base to 5s, and channel A to 5mV amplitude. Click on „start‟ at bottom right, and ask your subject to abduct the little finger (i.e.make a voluntary contraction) – check that you can see a raw EMG signal, and adjust the scale for the Y-axis of channel A input to fit the amplitude of the EMG signal.

Step 2. Per-cutaneous stimulation of the ulnar nerve. Moisten the tips of the stimulating electrodes with saline, and ask your subject to place them firmly on the skin over the ulnar nerve at the wrist, cathode distal. Check that the stimulator switch on the Powerlab control unit is set to „on‟. Set the time base on the screen to 20ms. Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse. Each successive stimulus will trigger a recording period of about 20 ms, and these will be stored on screen as separate „pages‟. Gradually increase the stimulus strength until you get an EMG response from the muscle. The absolute maximum stimulus amplitude that can be delivered by the stimulator is 20 mA, but it should not be necessary to exceed 10mA if you have the electrodes in the right place, and for many subjects the stimulus strength required may be a lot less.

Step 3. Mark the exact position of the cathode, and measure the distance from that point to the mid-point of the muscle. Keep this EMG trace (making a note of its page number as you will need to find it again) but delete the failed trials made so far.

Step 4. Now stimulate the ulnar nerve at the back of the elbow (again, start at a low stimulus amplitude) and record the EMG again – you are looking for an EMG response of the same shape as before, but which starts later. Mark the exact position of the cathode on the subject‟s skin, and measure the distance to the mid-point of the muscle again.

Step 5. Print selected traces or save them for later analysis. From the difference between distances (stimulus point to muscle mid-belly), and difference in time to the start (or any other clear feature) of the EMG response, you can calculate the conduction velocity over the forearm segment of the ulnar nerve.

1.1.2) Version 2 for the Median nerve motor conduction velocity:

The subject should sit in a chair with a back. Place the two adhesive recording electrodes on the base of the thumb over the Abductor pollicis brevis (APB) muscle, and place the earth electrode on the back of the hand. Connect these electrodes to the recording leads using the crocodile clips. The lead for the

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earth electrode is green or is identified by a green & yellow tag on the lead. It does not matter which way round the other two electrodes are connected. The other end of the recording leads should be connected to the Powerlab (or equivalent) computer used to make the recordings. Proceed as follows:

Step 1. Check the system is working and you can record EMG. With the „NCV‟ program open, set the recording time base to 5s, and channel A to 5mV amplitude. Click on „start‟ at bottom right, and ask your subject to make a pincer grip (thumb to middle finger) and check that you can see a raw EMG signal. Adjust channel A‟s Y-axis scale if necessary.

Step 2. Per-cutaneous stimulation of the median nerve. Moisten the tips of the stimulating electrodes with saline, and ask your subject to place them firmly on the skin over the median nerve at the wrist, cathode distal. The correct position is just lateral to the mid-line. Set the time base to 20ms. Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse. Each successive stimulus will trigger a recording period of about 20 ms, and these will be stored on screen as separate „pages‟. Gradually increase the stimulus strength until you get an EMG response from the muscle. The absolute maximum stimulus amplitude that can be delivered by the stimulator is 20 mA, but it should not be necessary to exceed 10mA if you have the electrodes in the right place, and for many subjects the stimulus strength required may be a lot less.

Step 3. Measurements Mark the exact position of the cathode, and measure the distance from that point to the mid-point of the muscle. Delete unwanted recordings and save some good ones for later (make a note of the page numbers, as you will need to find them again).

Step 4. While the recording electrodes are still on the skin over APB, move the stimulating electrodes to the elbow, over the point where the median nerve lies at the elbow, just medial to the biceps tendon, and try stimulating it here. Once again, start with a low stimulus amplitude, and increase this in small increments until you get an EMG response from APB. You are looking for an EMG response of the same shape as before, but which starts later. Mark the exact position of the cathode on the subject‟s skin, and measure the distance to the mid-point of the muscle again.

Step 5. Print selected traces or save them for later analysis. From the difference between distances (stimulus point to muscle mid-belly), and difference in time to the start (or any other clear feature) of the EMG response, you can calculate the conduction velocity over the forearm segment of the median nerve.

1.2) Non-invasive recording of a sensory nerve conduction velocity

It is possible to mimic a natural stimulus by electrically stimulating the digital nerve in the finger, and then recording the passage of action potentials (as the compound action potential, the CAP) propagated orthodromically towards the central nervous system as they reach the wrist. Electrical stimulation is most reliable for this sort of experiment because it ensures simultaneous excitation of a sufficient number of axons to give a signal that is just large enough to record percutaneously and can be standardized to give reliable repetition. The small size of the CAP means that it is usually necessary to average recording from a small series of identical trials – this reduces the amplitude of the (electrical) noise while preserving the consistent signal due to the CAP.

Alternatively, recording electrodes are placed around the finger to detect the CAP in the digital nerve. When sensory axons are excited by stimulating them electrically at the wrist, the latency of the CAP allows us to measure conduction velocity of nerve action potentials conducted antidromically towards the finger.

If the distance between the stimulating electrode (cathode) and the recording electrode closest to it (d), and the time (latency) between stimulus and the start of the CAP (t), are measured, the conduction velocity (v) of these afferent neurons can be calculated:

Ring electrodes used to stimulate or record from digital nerves of the middle and little (5th digit) fingers consist of two flexible metal rings, clipped together with an adjustable connector to fit snugly around the finger. Smear some electrode gel on the inner surface of these electrodes before clipping them around the finger, to ensure good electrical contact.

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1.2.1) Version 1 for Ulnar nerve, orthodromic sensory conduction:

Step 1. Clip the ring electrodes to fit snugly around the little finger, and connect them to the stimulator output ports of the PowerLab control unit. Place one full-size adhesive silver tab electrode over the ulnar nerve 1cm from the wrist crease and over the ulnar border (the long axis of the electrode should be parallel to the course of the nerve), and another full size adhesive silver tab electrode 3 cms proximal to it, also over the nerve. These two electrodes should not touch each other. Attach a half-width adhesive silver electrode tab over the 1st carpometacarpal joint of the thumb of the same hand and connect it to the earth lead of the recording electrodes.

Step 2 Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse. Starting at a low stimulus amplitude of 2 mA, increase the stimulus strength (single shocks only at this stage) until your subject is able to feel them; note this „threshold‟ amplitude. Set

channel A (connected to the recording electrodes) to the expected signal amplitude of ± 50 V and the time base to 20ms.

Then set the stimulator of the Powerlab so that it can deliver a series of identical stimulus pulses and average the responses recorded: Select in turn:

‘set up’ on the menu bar at the top of the screen

‘sampling’ menu

then in the ‘mode’ options select ‘average’, and 8 sweeps

OK

Then, back in the main screen, increase the stimulus amplitude to double the threshold amplitude, but leave the duration and delay unchanged.

Step 3 Ask your subject to sit back in his/her chair, and be prepared to stay still during the series of stimuli. Click on „start‟ – there will be a short interval between each stimulus and the next, and as successive responses are averaged you should see a change in the recorded response from initially an apparently random set of positive and negative fluctuations in the signal trace, to a trace which shows both a large stimulus artefact near the start, and a subsequent (probably smaller) response (the CAP) followed by a more or less stable baseline. If at first you see only stimulus artefact but no CAP, then increase the stimulus strength and try again. It may be necessary to increase the stimulus to the point where it is mildly uncomfortable, but it should NOT be increased to the point of being painful. If you can see the CAP but the trace is still very noisy, you could try averaging 16 rather than 8 responses to improve it.

Measure the distance between the cathode stimulating electrode and the nearest recording electrode. Save the (useful) recordings.

1.2.2) Version 2 for Ulnar nerve, antidromic sensory conduction:

Step 1 Connect the recording electrode leads to the flexible ring electrodes around the little finger. Moisten the tips of the stimulating electrodes with saline, and ask your subject to place them firmly on the skin over the ulnar nerve at the wrist, cathode distal. Check that the stimulator switch on the Powerlab control unit is set to „on‟. Set channel A (connected to the recording electrodes) to the expected signal amplitude of

± 50 V and the time base to 20ms. Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse.

Step 2 Gradually increase the stimulus strength until you get a small CAP wave on the screen. Then set the stimulator of the Powerlab so that it can deliver a series of identical stimulus pulses and average the responses recorded: Select in turn:


‘sampling’ menu


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OK

Back in the main screen, leave the stimulus parameters unchanged for now.


Print or save traces for later use. Measure the distance between the cathode stimulating electrode and the nearest recording electrode.

1.2.3) Version 3 for Median nerve, orthodromic sensory conduction:

Step 1 Fit the stimulating (ring) electrodes snugly around to the middle finger, and put full size adhesive recording electrodes on the skin over the median nerve at a position mid-wrist 1cm from wrist crease, 3cms between anode and cathode. Connect both sets of electrodes to the Powerlab (or equivalent) computer and open up the „scope‟ recording mode. Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse. Then, starting at a low stimulus amplitude of 2 mA, increase the stimulus strength (single shocks only at this stage) until your subject is able to feel them; note this „threshold‟ amplitude. Set channel A (connected to the recording electrodes)

to the expected signal amplitude of ± 50 V and the time base to 20ms.

Step 2 Then set the stimulator of the Powerlab so that it can deliver a series of identical stimulus pulses and average the responses recorded: Select in turn:


‘sampling’ menu


OK

Then, back in the main screen, increase the stimulus amplitude to double the threshold amplitude, but leave the duration and delay unchanged.



1.2.4) Version 4 for Median nerve, antidromic sensory conduction:

Step 1 Moisten the tips of the stimulating electrodes with saline, and ask your subject to place them firmly on

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the skin over the median nerve at the wrist, cathode distal. The correct position is just lateral to the mid-line. Set the time base to 20ms and channel A (connected to the recording electrodes) to the expected

signal amplitude of ± 50 V and the time base to 20ms. Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse. Connect the recording electrode leads to the flexible ring electrodes around the finger (and an earth electrode on the back of the hand; this should be connected to a green lead). Start with a small stimulus amplitude, and increase it in small increments until a small CAP wave is recorded.

Step 2 Then set the stimulator of the Powerlab so that it can deliver a series of identical stimulus pulses and average the responses recorded: Select in turn:


‘sampling’ menu


OK

Then, back in the main screen, leave the stimulus parameters unchanged for now.



2) Muscle force regulation and motor unit ‘recruitment’ investigations using EMG recordings

This protocol can apply to any nerve and muscle combination where the nerve comes close to the skin at a convenient point for stimulation, and the muscle is also fairly superficial, so the EMG activity can be easily recorded using standard adhesive electrodes placed on the skin over the muscle. Clean the skin over the muscle first with a swab, and allow it to dry before attaching the adhesive recording electrodes to the skin. The recording electrodes should be placed over the muscle and the earth electrode at some distance to the active muscle over tissue which is not innervated by the nerve. Connect the electrodes to the recording leads using the crocodile clips. The green lead (or lead with a green & yellow tag) is the earth lead; it does not matter which way round the other two recording electrodes are connected. The other end of the recording leads should be connected to the Powerlab (or equivalent) computer used to make the recordings.

2.1) Version 1: EMG and recruitment

Step 1. EMG recorded during voluntary contractions of increasing strength. Open up the „oscilloscope‟ recording mode on the Powerlab (e.g. via clicking on the „NCV‟ icon), and start by setting the recording time base to 5 or 10s as preferred, and channel A to 5mV amplitude. Click on „start‟ at bottom right, and ask your subject to activate the muscle (i.e.make a voluntary contraction) – check that you can see a raw EMG signal, and adjust the scale for the Y-axis of channel A input to fit the amplitude of the EMG signal. You may need to make a few trials to get this right.

Now ask your subject to make three short (about 1-2 sec each) voluntary contractions of this muscle, in order one weak, one moderate and one strong, as soon as you start the next recording period. Again, you may need to make a few trials to get it right. The subject should be allowed to rest for a minute or so between trials.

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Remember to record and/or print a good example. There should be an obvious increase in the size and number of components within the EMG signal for each successive contraction, reflecting both the number of motor units activated and their frequency of firing.

[n.b. a more extensive variant of this part of the experiment is described in Protocol 2.1, Version 2: Grip force and EMG during an isometric contraction]

Step 2. EMG evoked by single stimuli of increasing strength to the nerve. Moisten the tips of the stimulating electrodes with saline, and ask your subject to place them firmly on the skin over the nerve at a convenient point (where it is relatively superficial), cathode distal. Check that the stimulator switch on the Powerlab control unit is set to „on‟. Set the time base on the screen to 20ms. Set the stimulus duration to 0.2 ms, amplitude to 2 mA and delay to 0 ms, and click on start to deliver a stimulus pulse. Each successive stimulus will trigger a recording period of about 20 ms, and these will be stored on screen as separate „pages‟. Gradually increase the stimulus strength until you get an EMG response from the muscle. It is important to have the stimulating electrode immediately over the nerve, so that the threshold stimulus for getting a motor (EMG) response is quite small.

Step 3 Now that you know the correct position for the stimulating electrode and the threshold stimulus intensity, record the responses to a series of gradually increasing stimulus strengths. The absolute maximum stimulus amplitude that can be delivered by the Powerlab stimulator is 20 mA, but if you have the electrodes in the right place, and a low threshold stimulus, you should find that for most subjects you reach an obvious maximum response size well before that point. This part of the experiment, which involves single shocks only and so excludes the „rate recruitment‟ effect, therefore models the motor unit recruitment effect only, as stronger stimuli activate (recruit) more axons in the nerve supplying the muscle. When you have a good example, save the series of responses and/or print them superimposed on the same screen.

2.2) Version 2: Grip force and EMG during an isometric contraction

Step 1: setting up The Powerlab should be used in „chart‟ mode (Chart5 for Windows) for this investigation, EMG and grip force or recorded simultaneously as the subject carries out isometric exercise of forearm muscles using a handgrip dynamometer. Connect the dynamometer to the the Powerlab control box so that its output will be displayed on channel 1 (with range 20 mV, which can be adjusted later if necessary), and place conventional adhesive silver tab recording electrodes on the forearm over the deep flexor muscles. The position is just medial to the midline in the proximal third of the forearm. To find the best position, ask the subject to grip the dynamometer tightly, and palpate the forearm to find the belly of the muscle. Connect these electrodes to the red and blue recording leads from the white pre-amplifier box, and connect the black lead to the earth electrode on the back of the hand. The pre-amplifier is connected in turn to the isolator/filter/RMS integrator unit, whose output is connected to channel 2 of the Powerlab control unit.

An alternative to using the isolator/filter/RMS integrator unit which rectifies and smooths the EMG signal before sending it to the Powlerlab, you can record raw EMG (sending it direct to the Powerlab) and then later use the mathematical functions available in LabChart Reader to carry out this operation on saved data files.

Step 2 To check that you have the right settings for signal amplitude (both channels), ask your subject to make a very brief maximal contraction (gripping the dynamometer), and adjust the channel 1 and channel 2 Y-axis amplitude ranges to ensure that the maximal response will not go off screen.

Step 3 Start the experiment with the subject holding the dynamometer loosely (not exerting any force on it). Because the dynamometer is heavy, your subject will have to support the weight of the hand+dynamometer with the other hand (this avoids recruiting the muscle just for postural purposes). Set the chart recorder time base to 100:1, and start a recording period with a short baseline period of 10-20 sec (no grip force), then ask your subject to increase his/her grip force to the maximum possible, and attempt to maintain this force until the point of significant fatigue (and loss of force). Depending on your

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subject this could be anything from 1-5 minutes. Print or save the traces.

Step 4 Once your subject has recovered from the fatiguing contraction (a few minutes), ask him/her to try a series of short contractions (about 5-10s each, with at least a minute rest between each one) at intermediate grip forces (roughly 20%, 50% and 75% of the maximum initially recorded). Measure the mean amplitude of the force trace and the EMG in each period

3) Determination of the isometric contractile properties of the triceps surae using percutaneous stimulation.

A dynamometer specially designed for measuring the contractile properties of the triceps surae (the ankle plantar flexors) is used.

Step 1: Setting up. The subject sits upright in the dynamometer with knee flexed, thigh horizontal and the foot resting on the wooden boards. The clamp placed and tightened over the distal portion of the thigh prevents movement

during contraction. The position of the foot is moved so that the ankle joint is at an angle of 85. Percutaneous stimulating electrodes (carbonised conductive rubber, smeared with electrode gel) are placed over the heads of the gastrocnemius (positive electrode) and the over the belly of the soleus (negative electrode). Fix the electrodes in place with Millipore tape and then a Velcro strap. Signals from the strain gauge are amplified and fed to a suitable computer running data acquisition software. A stimulator controlled by a digital timer, which can also be linked to the data acquisition unit, is used to deliver stimuli of the desired amplitude, duration and frequency.

Step 2. Determination of stimulus response Single stimuli (0.05 ms square wave current pulses) are delivered to the muscle. Increase the current delivered to the muscle by 20mA separated by ~30s intervals, but do NOT increase stimulus duration. Continue until the twitch size reaches a maximum, and record three twitches at this current. At this very short pulse width (0.05ms) the current required from the stimulator (Digitimer DS7 – designed specifically for human experimentation) may be up to 1000mA. Record what happens to the size and time course of the twitch with increasing stimulus amplitude, and the time course of the maximum twitch response (TPT, 1/2RT)

Step 3. Determination of frequency response Reduce the current to a lower level (approx 50% of the amplitude needed for the maximum twitch, or as much is tolerable by the subject), then, maintaining this level of current, evoke 1s contractions at 5, 8, 10, 15, 20, 30, 50, 100 and 200 Hz frequency. Record what happens to the force, the rate of force production, the amplitude of the oscillations.

Step 4. Determination of maximum voluntary force Ask the subject to perform a maximum voluntary contraction (MVC), whereby the subject plantar flexes the foot for ~2-3s with maximum effort.

Step 5. Determination of muscle activation using twitch interpolation Ask the subject to perform 100% of MVC for ~5 s and record this. Repeat this after a suitable rest period and as soon as a steady force has been achieved deliver a maximal twitch using the parameters determined in step 1. Record what happens to the size of the superimposed twitch. After the 100% MVC and the muscle has relaxed deliver a single twitch to the muscle. Record what happens to the amplitude of the subsequent twitch.

4) Knee extensor muscle function muscle assessed using isokinetic dynamometry

The apparatus to be used is a KinCom isokinetic dynamometer, which will only allow a joint to rotate through a prescribed range of movement (which is set by the experimenter and which prevents movement outside the normal range for each subject, so excluding hyperextension) at constant (pre-set) angular velocity (in this instance up to 500°s-1).

Step 1: Setting up The subjects sits in the dynamometer, which is then adjusted so that the angle of rotation of the knee joint is aligned with the rotational axis of the dynamometer head. Ensure that subjects are allowed to

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rest between trials so that the muscles are “fresh” for each trial. Forces and displacements from the dynamometer are recorded by data acquisition software running on a PC. Remember to calibrate the equipment for force and displacement.

Step 2: Angle torque relationship and muscle strength Ask the subject to perform a maximal isometric (static) knee extension lasting 2-3 seconds at a series of angles ranging from 90° (of flexion) – 150° (180° represents full extension). Allow 30 s rest between trials.

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Step 3: Concentric torque -angular velocity relationship. Perform 2 maximal dynamic contractions at each angular velocity up to 300°s-1. Allow 30 s rest between trials.

Step 4: Eccentric muscle forces From near full leg extension resist the lever arm as it forces the leg into flexion. Perform this so the lever arm rotates at 60 and 120°s-1. Allow 30 s rest between trials.

Step 5: Anthropometric measurements These are required to be able to normalise force to muscle volume and/or body weight. Using a tape measure, measure the size of the thigh at its widest point (~mid thigh) (this gives muscle + bone cross-sectional area). For an estimate of thigh volume, measure the circumference of the thigh at three points: i) At the gluteal fold, ii) mid thigh (as above) and iii) just above the knee. This creates 2 truncated cones whose volume needs to be added together to make the total.

Step 6: Power output measured with the Nottingham Power Rig The Nottingham power rig was designed to measure the power output of the leg muscles of elderly people and works on the basis of power being calculated from a single lower limb thrust against a flywheel with a high inertia. The apparatus is designed such that the subject is protected from its moving parts.

The subject sits in the apparatus. Adjust the position of the seat so that the subject is comfortable, and his/her leg can almost fully extend the knee (n.b. the movement does not allow the knee to hyperextend.). The subject performs 6 maximal pushes; allow 30 s rest between trials. Record the power generated from each push.

5) An investigation of factors contributing to Muscle fatigue.

This practical uses a standardised test of muscle fatigue to characterise the fatigue resistance of the calf muscle. A dynamometer specially designed for measuring the contractile properties of the triceps surae (the ankle plantar flexors) is used.

Step 1: Setting up. The subject is seated upright in the dynamometer with knee flexed, thigh horizontal and the foot resting

on wooden boards. The position of the foot is moved so that the ankle joint is at an angle of ~85. Percutaneous stimulating electrodes (carbonised conductive rubber, smeared with electrode gel) are placed over the heads of the gastrocnemius (positive electrode) and the over the belly of the soleus (negative electrode). Fix the electrodes in place with Millipore tape and then a Velcro strap. Stimulation of the muscle is by means of a stimulator controlling amplitude, and duration and frequency controlled by a digital timer, which can also be linked to the data acquisition unit. Adhesive silver tab EMG electrodes should be placed over the lower part of the triceps surae (on the most distal portion of the soleus muscle as far away from the stimulating electrodes as possible), and connected to the recording apparatus. The earth lead (coded green) should be placed over the shin of the opposite leg. These recording electrodes will record the mass action potential (M-wave) which is an indicator of muscle “excitability”.

Step 2: Characterisation of fatigue. Stimulate the muscle with square wave pulses (0.05ms) at a frequency of 20Hz for a period of 300ms. Find a current intensity that is comfortable for the subject and which produces a reasonable amount of force. Stimulate the muscle for 300ms and leave 700ms for recovery. Repeat this 120 times (i.e. 2 for minutes). Allow the subject to rest for 10 minutes. Repeat the test, this time reduce the recovery period between each contraction to 400ms. This will give 700ms cycle time. Measure the force generated by every tenth contraction. Measure the amplitude and the duration of the M-wave on every tenth contraction.

Step 3: Effect of circulatory occlusion on muscle fatigue On a separate subject stimulate the muscle with square wave pulses (0.05ms) at a frequency of 20Hz for duration of 300ms. Find a current intensity that is comfortable for the subject and which produces a reasonable amount of force. Stimulate the muscle for 300ms and leave 700ms for recovery. Repeat this 120 times (i.e. 2 for minutes) to obtain a baseline measure of muscle fatigability. Following ten minutes recovery place an inflatable cuff around the thigh and inflate it to 180 mmHg. Repeat the experiment keeping the duty cycle (i.e. 300ms on 700ms off) the same. Measure the force generated by every

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tenth contraction. Measure the amplitude and the duration of the M-wave on ever tenth contraction. The cuff is inflated as rapidly as possible (this should take approximately 20 seconds) and as soon as 180mmHg is reached the experiment begins. Immediately after the final contraction the cuff pressure is released.

Step 4: Effect of stimulation frequency on muscle fatigue Position the subject as previously described. Find a current intensity that is tolerable for the subject. Stimulate the triceps surae for 20s using a frequency of 200Hz, and then lower the stimulus frequency to 20Hz for an additional 2s. Measure the force after 1 second and after 20 seconds. Measure the amplitude and the duration of the M-wave.

Step 5: Effect of prior concentric and eccentric exercise on muscle force at different frequencies. The subject should step up and down from a box for 20 minutes (approximately 1 step per second) always using the same leg to climb and the other to lower from the box (this is so that one leg does concentric exercise (raising the body) and the other does eccentric exercise (lowering the body)). This box is relatively low (adjusted to be lower than the height of the subject‟s knee) and made of strong material with rubber feet to avoid slippage; an experimenter will be present to monitor the subject throughout the exercise bout. After 60 minutes rest, position the subject in the dynamometer as for step 1. Stimulate the calf muscle of the eccentrically-exercised leg at a moderate intensity for 2 seconds at 10, 20 and 50Hz (see step 2). Repeat this protocol with the other (concentrically-)exercised leg to compare performance.

6) Reflexes

6.1) Stretch reflex

Step 1: Setting up A Powerlab (or equivalent) computer setup operating in „oscilloscope‟ mode is used in conjunction with a patella hammer incorporating a microswitch. When the hammer is tapped against something it will send a signal to the computer to begin recording. To do this the 9V battery must be attached to the hammer and the "Start" button in the bottom right corner of the screen clicked to tell the computer to be ready to receive the signal. Also, set the Powerlab to recognise there will be an external trigger as follows. Select:

‘Set up’ menu Sampling Mode = single Source = external OK

Have the subject stand with his/her leg bent and knee rested on a low chair as shown below.

Clean an area of skin over the calf muscle with the alcohol wipes, and then attach two of the adhesive silver electrode tabs.

The third Earth electrode can be placed anywhere out of the way (e.g. over the lateral malleolus). Attach the crocodile clips to the electrode tabs.

You will probably have to remove the shoe of the foot that is hanging free, to expose the Achilles tendon.

The subject faces the chair as shown, holding the top of the back of it, and rests one knee on the seat so the foot hangs loosely.

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Step 2 Check the recording apparatus is working and you do not have a "noisy" reading. Have one of your group place their hand on the ball of the subject's foot so they have some resistance to push against. Click the Start button, tap the hammer on a bench, record a second or so while the muscle is relaxed, and then ask the subject to push and relax again as the computer records the rest of the 5 seconds. There should be no significant EMG while the muscle is relaxed, but then a burst of activity throughout the contraction phase.

Step3: practice triggering the subject's reflex. Forget about using the computer for a moment, since there is no point recording anything until you are confident you can get the reflex. Using the hammer, lightly tap the Achilles tendon at an oblique angle. Your intention is to stretch the tendon, not flatten it! The person using the hammer should devote their attention to the subject's foot (does it move ?), not try to watch the computer screen while trying to hit the tendon.

Step 4 Once you have the reflex, change the "Time Base" setting on the screen to 100ms, click the Start button and tap the tendon.

While the traces are still on the screen, measure the latency to the EMG response, to check if it is sensible (i.e. that you are recording the right response: to do this, you will need to measure the distances involved from stimulus point to spinal cord, and from spinal cord to muscle, allow 0.5 ms per synapse for synaptic delay and assume conduction in the efferent arm of the reflex is 50m/s ). Adjust stimulus position or intensity as required, and repeat until you have 4 good traces, and save at least one example to file.

Step 5 You may wish to test the effect of the Jendrassik manouevre on the stretch reflex. Ask your subject to adjust his grip on the chair back: (s)he should grip as hard as possible, while simultaneously trying to pull the grip points together. This activates as much upper body musculature as possible; now repeat another stimulus, and record the response.

Once you have finished, the adhesive EMG electrode tabs should be placed in the clinical waste bin.

6.2) Hoffman Reflex.

The aim is to selectively stimulate only the largest (fast-conducting) afferents in the nerve, which will be predominantly from muscle spindles. If you succeed, this should also elicit a reflex response from the muscle, at a latency appropriate to the conduction distances (afferent and efferent) involved. The leg will need to be fairly straight for this experiment, so the subject should lie face down on a couch close to the recording equipment.

Step 1: To stimulate the nerve you will have to change some of the settings on the Powerlab computer. Under "Setup" you will find "Sampling" -change "Trigger" from "External" to "User". Also under "Setup", go to "Stimulator" and change "Off' to "Pulse". This switches on the Stimulus Isolator and switches off the need to use the hammer to start recording.

Set the stimulating current to 3mA to start with, and change the stimulus duration to 0.5ms, but do not change the Delay setting. Also, set the stimulator to deliver single current pulses.

Step 2 The subject should be lying face down on a couch or on a mattress placed on the floor. Place electrodes on the outer or inner side of the subject's calf muscle; the cathode (black lead) should be placed over the belly of the gastrocnemius muscle, and the anode (red lead) about 5 cm distal to it. As always, clean the skin beforehand and place the Earth electrode tab out of the way. Set the Y-axis scale of channel A to 5mV. Set the time base to 5s and ask the subject to activate the muscle while you check that EMG is recorded. Then change the timebase back to 50ms.

Moisten the pads on the end of the red and black stimulus electrodes with the saline and place in over the nerve at the back of the knee. Which nerve you use will depend on whether you placed the recording electrode on the outside or inside of the calf, but we suggest you try first the medial

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gastrocnemius. If this does not work move the recording electrode to a relatively lateral position overlying soleus. In either case the correct nerve stimulation points are inward of the tendons at the back of the knee. You may be able to feel a pulse here, as the position of the arteries is closely associated with those of the nerves in this region.

Step 3 Set the „display‟ menu to „overlay all‟, click on „start‟ to deliver a stimulus and repeat at intervals of a few seconds. During the series of stimuli, move the stimulating electrodes slightly until you find a position which gives an EMG response on the screen in co-incidence with a just visible contraction of the muscle. This EMG response (= M wave) will probably have a latency of about 5ms. If there is no EMG response, increase the stimulus amplitude until you get one. Then try reducing the stimulus strength again in small increments so that the initial EMG response decreases in amplitude, and look to see if any trials result in an additional longer latency small EMG response (H response) at about 35ms.

This longer latency response (the H reflex) is quite difficult to obtain, as you have to have the electrodes in exactly the right place to preferentially stimulate low-threshold sensory axons. In the hands of novice experimenters the success rate is quite low, so don‟t blame your subject if you can‟t find the longer latency response ! Just increasing the stimulus strength will NOT increase your chances of finding it, as it works best at low stimulus strengths.

If you get a good example, while the trace is still on the screen, measure the latency to the two EMG responses, and save the file. You can use the traces in conjunction with measurement of the appropriate distances (from stimulus point to muscle, from stimulus point to lumbar spinal level, and from lumbar spinal level to EMG recording point), to calculate motor conduction velocity (use the M wave latency and distance between cathode stimulating electrode and nearest recording electrode), and conduction velocity in the afferent arm of the reflex (using the latency to the second, longer latency EMG response and the appropriate distances).

Once you have finished, the adhesive EMG electrode tabs should be placed in the clinical waste bin.

7) Reaction times.

Reaction times test the time taken for a subject to perceive and respond to a stimulus, and so involves the participation of much more CNS circuitry than for a simple stretch reflex. In this case the subject, seated comfortably in a chair with a back, holds a small push button switch connected to a Powerlab computer and presses the switch as soon as possible after the appearance of a sensory stimulus e.g. a visual stimulus on the computer screen.

Connect the push-button switch to channel 2 on the front of the Powerlab, and open up the „scope‟ program. Set channel 2 range to 10V, and time base to 5s (in the first instance). Connect a patella hammer (with its own independent power supply in the form of a 9v battery), to the „trigger‟ input of the Powerlab control box.

When the hammer is tapped against something it will send a signal to the computer to begin recording. To do this the 9V battery must be attached to the hammer and the "Start" button in the bottom right corner of the screen clicked to tell the computer to be ready to receive the signal. Also, set the Powerlab to recognise there will be an external trigger as follows. Select:

‘Set up’ menu Sampling Mode = single Source = external OK

The experimenter using the tendon hammer to trigger the recording period should stand behind the subject, so that no preparatory movements can be seen by the subject. The only signal that the subject should be responding to is the sensory one triggered when the hammer is tapped; so, for example, if the sensory signal is visual on the screen, make sure that there is no auditory signal associated with the trigger „tap‟ that the subject can hear. The subject should depress the push button as soon as possible after the appearance of the sensory cue. This will be recorded on channel 2 as a brief square wave voltage pulse. Measure the latency from start of the trace (when the visual cue was displayed) to the start of the response pulse, and repeat several times to obtain an average value (+/- s.d.).

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8) Gait examined by means of footprint analysis (pedograph) system

This analysis is very simple to do, yet can provide a lot of (clinically useful) information about gait. In essence, the subject walks barefoot for a set distance (usually 7m) along a strip of paper which is treated to show up his footprints. From the footprints (and the time taken to cover this distance) it is possible to obtain all of: stride length, step length, foot angle and cadence.

There are two ways of doing this:

Method A: a 7 meter strip of fairly thick wallpaper is fixed to the floor, and its upper surface covered with a layer of water-based coloured paint. Carefully lay a strip of thinner paper on top, and ask your subject to walk along the strip, starting on the command „go‟. The experimenter should record both the start time and the time when the subject reaches the end point. The weight of the subject at the point of foot contact will result in an „impression‟ of his footprints showing through the top paper strip.

Method B: a 7 meter strip of wall paper is fixed to the floor, the subject „inks‟ the soles of his feet with water-based coloured paint and then walks along the strip, starting on the command „go‟. The experimenter should record both the start time and the time when the subject reaches the end point. The paint will be transferred from the subject‟s feet to the paper strip at all points of foot contact leaving footprints.

Measure in cm, using the tape measure provided:

a) The foot angle.

b) Stride width (the lateral distance from the centre point of the left foot to the centre point of the right foot)

c) Step length (the longitudinal distance from one footprint to the next, using the back of the heel as the reference point)

d) Stride length (the longitudinal distance between prints from the same foot, e.g. from right to the next right; same reference point)

e) Cadence (the mean step time) i.e. the time taken to walk the X meter distance divided by the number of steps taken.

9) Tests of balance.

9.1) Romberg test

This is one of the tests that can be used to check if people who having been drinking alcohol are fit to drive, as well as being part of a standard clinical neurological examination (looking for signs of permanent nervous system damage).

Step 1 Ask your subject to stand with his/her feet together (touching each other), and looking at a mark on the wall at eye height about 2 meters away, and check for stability. An individual with normal balance should show little or no sway (you could just observe this, or measure sway by one of the methods described below).

Step2 Then ask your subject to close his/her eyes and continue to stand quietly for 1 minute. At least one experimenter should remain close at hand (to provide support if need be) in case the subject begins to sway or fall. Can your subject remain standing like this without any change of foot position or falling ? Record the results of several trials.

The Tandem Romberg Test is a more sensitive variant. In this case the subject stands with feet in-line [heel to toe], and carries out the same procedure as above.

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9.2) Star excursion balance test (SEBT)

To perform the SEBT, the subject stands on one leg (=stance leg) in the centre of the „star‟ grid marked out on the floor (see diagram below) while reaching out with the contra-lateral leg (= reach leg) as far as possible along the appropriate vector line.

See over for the star grid:

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SEBT - the star grid:

(S)he should very lightly touch the line with the toes (NOT using the reach foot for support), and then return to a bilateral stance to rest while maintaining equilibrium. One experimenter must always be on hand to provide support if a subject begins to fall. Another experimenter measures the distance from the centre of the grid to the touch point.

Three reaches in each direction are recorded and subjects are given 15 seconds of rest between reaches. Reach leg (right, left), order of excursions performed (clockwise, anticlockwise), and direction of the first excursion (A, M, L, P) should be counterbalanced to control for any learning or order effect.

Trials are discarded if: (1) the reach foot is used to widen the base of support (i.e. is actually used to support the body weight), (2) the reach foot does not touch the vector line, (3) the subject moves the stance foot from the centre of the grid or loses balance at any point in the trial, or (4) if the subject cannot maintain start and return positions for one full second.

9.3) Measurement of sway.

Various methods are available, and in all cases you should measure sway with the subject standing still with feet 4 cm apart, arms folded in front of chest, initially with eyes open and looking at a marker on the wall in front of him/her, and then with eyes closed. In healthy subjects the sensitivity of the balance test can be enhanced by standing on foam. The subject should attempt to maintain position for 1 minute (unless otherwise specified) in each case. One experimenter must always be on hand to provide support if a subject begins to fall, while other experimenters run the test by setting the start & stop times, making recordings, checking recording equipment is working correctly, etc. You will be provided with the equipment to carry out the following tests:

9.3.1) Measurement of lateral sway, using a small laser pointer fixed to the standing subject.

A small laser pointer is fixed to the subject at one of the following positions(sternum, waist or anterior superior iliac spine) using a flexible strap, and aimed at the wall in front of the subject. The wall is covered with a large sheet of white paper, with an eye-level marker point (appropriate for the particular subject) near top centre. Two experimenters stand either side of the paper sheet, and mark (with a pencil) the most lateral points reached by the light beam. You should mark the extreme of EACH of, say, 20 successive sway maxima in each direction so as to allow calculation of a mean ±sd.

CARE – do not ever aim the laser beam at anyone’s face.

Stance foot

position

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9.3.2) Measurement of anterior-posterior sway using a wire Goniometer or optical Goniometer attached to the ankle.

The wire goniometer device measures the distance from the fixed point of the wire Goniometer attached to the wall and the part located at the back of the ankle (to which it is fixed using a Velcro strap). As the wire moves in and out of the Goniometer on a spring-loaded potentiometer, voltage across the potentiometer varies in relation to the distance pulled. The voltage is calibrated to mm travelled and recorded on a PowerLab.

The optical goniometer measures the change in angle in one degree of freedom of the ankle joint. The angle is determined by the amount of light passing through a pair of optic fibres running along either side of a 200mm vinyl-covered metal cantilever. Two plastic enclosures are attached to either end of the cantilever. One enclosure contains the electronics that convert the light signal from the sensor to an electrical output which you should connect directly to a PowerLab Pod port.

The device should be fixed on one side of the ankle (medial or lateral, as preferred) so the centre of the cantilever lines up with the turning centre of the ankle joint. This should also be done in the neutral axis of the joint (i.e. with the ankle in the mid-range of its range of motion) to minimize length differences between the joint and the sensor as the joint moves through the range of motion due to sway. The plastic enclosures are attached to the cantilever brackets using double-sided tape and secured to the limb using the Velcro straps, one a few cm above the ankle and one roughly midway along the foot. The recordings are made in „chart‟ mode on the Powerlabs.

Whichever device you use, you will need to carry out several trials (1 minute each), to obtain a mean ±sd value.

9.3.3) Measurement of lateral and anterior-posterior sway on a wobble (or sway) platform.

The wobble platform is instrumented with strain gauges placed on the four surfaces of a central column. These detect tilt of the platform in 2 dimensions (anterior-posterior and lateral) as the subject sways.

You should examine sway both with and without a layer of stiff foam between the subject‟s feet and the top surface of the platform. The output of the strain gauges are fed to the Powerlab where it can be displayed in real time. Use the „chart‟ recording mode for this, and record for 2 minutes in each condition.

When you carry out the test, the subject‟s feet should be in the centre of the platform, about 4 cm apart.

You will need to carry out several trials (2 minute each), to obtain a mean ±sd value.

9.4) Berg Balance test .

Strictly, this is called the Berg Balance Scale, and was developed to measure balance among older people with impairment in balance function (and therefore at increased risk of falling) by assessing the performance of functional tasks. It is a validated 14-item test needing only a ruler, two standard chairs (one with arm rests, one without), a footstool or step, stopwatch or wristwatch and 15 ft walkway marked out on the floor with masking tape.

The entire assessment (i.e. all aspects listed in the standard assessment form shown below) takes 15-20 minutes. Each criterion is given a score ranging from 0-4. “0” indicates the lowest level of function and “4” the highest level of function. Total Score = 56. Interpretation: 41-56 = low fall risk, 21-40 = medium fall risk, 0 –20 = high fall risk. A change of 8 points is required to reveal a genuine change in function between 2 assessments.

Detailed instructions, including a score card (overleaf), are as follows:

Please document each task and/or give instructions as written. When scoring, please record the lowest response category that applies for each item.

Subjects should understand that they must maintain their balance while attempting the tasks. The choices of which leg to stand on or how far to reach are left to the subject. Poor judgment will adversely influence the performance and the scoring.

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In most items, the subject is asked to maintain a given position for a specific time. Progressively more points are deducted if:

the time or distance requirements are not met

the subject‟s performance warrants supervision

the subject touches an external support or receives assistance from the examiner Score card:

Name: __________________________________ Date: ___________________

Location: ________________________________ Rater: ___________________

ITEM DESCRIPTION SCORE (0-4)

Sitting to standing ________

Standing unsupported ________

Sitting unsupported ________

Standing to sitting ________

Transfers ________

Standing with eyes closed ________

Standing with feet together ________

Reaching forward with outstretched arm ________

Retrieving object from floor ________

Turning to look behind ________

Turning 360 degrees ________

Placing alternate foot on stool ________

Standing with one foot in front ________

Standing on one foot ________

Total score=________ Berg Balance Scale SITTING TO STANDING INSTRUCTIONS: Please stand up. Try not to use your hand for support. ( ) 4 able to stand without using hands and stabilize independently ( ) 3 able to stand independently using hands ( ) 2 able to stand using hands after several tries ( ) 1 needs minimal aid to stand or stabilize ( ) 0 needs moderate or maximal assist to stand STANDING UNSUPPORTED INSTRUCTIONS: Please stand for two minutes without holding on. ( ) 4 able to stand safely for 2 minutes ( ) 3 able to stand 2 minutes with supervision ( ) 2 able to stand 30 seconds unsupported ( ) 1 needs several tries to stand 30 seconds unsupported ( ) 0 unable to stand 30 seconds unsupported If a subject is able to stand 2 minutes unsupported, score full points for sitting unsupported. Proceed to item #4. SITTING WITH BACK UNSUPPORTED BUT FEET SUPPORTED ON FLOOR OR ON A STOOL INSTRUCTIONS: Please sit with arms folded for 2 minutes. ( ) 4 able to sit safely and securely for 2 minutes ( ) 3 able to sit 2 minutes under supervision ( ) 2 able to able to sit 30 seconds

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( ) 1 able to sit 10 seconds ( ) 0 unable to sit without support 10 seconds STANDING TO SITTING INSTRUCTIONS: Please sit down. ( ) 4 sits safely with minimal use of hands ( ) 3 controls descent by using hands ( ) 2 uses back of legs against chair to control descent ( ) 1 sits independently but has uncontrolled descent ( ) 0 needs assist to sit TRANSFERS INSTRUCTIONS: Arrange chair(s) for pivot transfer. Ask subject to transfer one way toward a seat with armrests and one way toward a seat without armrests. You may use two chairs (one with and one without armrests) or a bed and a chair. ( ) 4 able to transfer safely with minor use of hands ( ) 3 able to transfer safely definite need of hands ( ) 2 able to transfer with verbal cuing and/or supervision ( ) 1 needs one person to assist ( ) 0 needs two people to assist or supervise to be safe STANDING UNSUPPORTED WITH EYES CLOSED INSTRUCTIONS: Please close your eyes and stand still for 10 seconds. ( ) 4 able to stand 10 seconds safely ( ) 3 able to stand 10 seconds with supervision ( ) 2 able to stand 3 seconds ( ) 1 unable to keep eyes closed 3 seconds but stays safely ( ) 0 needs help to keep from falling STANDING UNSUPPORTED WITH FEET TOGETHER INSTRUCTIONS: Place your feet together and stand without holding on. ( ) 4 able to place feet together independently and stand 1 minute safely ( ) 3 able to place feet together independently and stand 1 minute with supervision ( ) 2 able to place feet together independently but unable to hold for 30 seconds ( ) 1 needs help to attain position but able to stand 15 seconds feet together ( ) 0 needs help to attain position and unable to hold for 15 seconds REACHING FORWARD WITH OUTSTRETCHED ARM WHILE STANDING INSTRUCTIONS: Lift arm to 90 degrees. Stretch out your fingers and reach forward as far as you can. (Examiner places a ruler at the end of fingertips when arm is at 90 degrees. Fingers should not touch the ruler while reaching forward. The recorded measure is the distance forward that the fingers reach while the subject is in the most forward lean position. When possible, ask subject to use both arms when reaching to avoid rotation of the trunk.) ( ) 4 can reach forward confidently 25 cm (10 inches) ( ) 3 can reach forward 12 cm (5 inches) ( ) 2 can reach forward 5 cm (2 inches) ( ) 1 reaches forward but needs supervision ( ) 0 loses balance while trying/requires external support PICK UP OBJECT FROM THE FLOOR FROM A STANDING POSITION INSTRUCTIONS: Pick up the shoe/slipper, which is in front of your feet. ( ) 4 able to pick up slipper safely and easily ( ) 3 able to pick up slipper but needs supervision ( ) 2 unable to pick up but reaches 2-5 cm(1-2 inches) from slipper and keeps balance independently ( ) 1 unable to pick up and needs supervision while trying ( ) 0 unable to try/needs assist to keep from losing balance or falling

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TURNING TO LOOK BEHIND OVER LEFT AND RIGHT SHOULDERS WHILE STANDING INSTRUCTIONS: Turn to look directly behind you over toward the left shoulder. Repeat to the right. (Examiner may pick an object to look at directly behind the subject to encourage a better twist turn.) ( ) 4 looks behind from both sides and weight shifts well ( ) 3 looks behind one side only other side shows less weight shift ( ) 2 turns sideways only but maintains balance ( ) 1 needs supervision when turning ( ) 0 needs assist to keep from losing balance or falling TURN 360 DEGREES INSTRUCTIONS: Turn completely around in a full circle. Pause. Then turn a full circle in the other direction. ( ) 4 able to turn 360 degrees safely in 4 seconds or less ( ) 3 able to turn 360 degrees safely one side only 4 seconds or less ( ) 2 able to turn 360 degrees safely but slowly ( ) 1 needs close supervision or verbal cuing ( ) 0 needs assistance while turning PLACE ALTERNATE FOOT ON STEP OR STOOL WHILE STANDING UNSUPPORTED INSTRUCTIONS: Place each foot alternately on the step/stool. Continue until each foot has touched the step/stool four times. ( ) 4 able to stand independently and safely and complete 8 steps in 20 seconds ( ) 3 able to stand independently and complete 8 steps in > 20 seconds ( ) 2 able to complete 4 steps without aid with supervision ( ) 1 able to complete > 2 steps needs minimal assist ( ) 0 needs assistance to keep from falling/unable to try STANDING UNSUPPORTED ONE FOOT IN FRONT INSTRUCTIONS: (DEMONSTRATE TO SUBJECT) Place one foot directly in front of the other. If you feel that you cannot place your foot directly in front, try to step far enough ahead that the heel of your forward foot is ahead of the toes of the other foot. (To score 3 points, the length of the step should exceed the length of the other foot and the width of the stance should approximate the subject’s normal stride width.) ( ) 4 able to place foot tandem independently and hold 30 seconds ( ) 3 able to place foot ahead independently and hold 30 seconds ( ) 2 able to take small step independently and hold 30 seconds ( ) 1 needs help to step but can hold 15 seconds ( ) 0 loses balance while stepping or standing STANDING ON ONE LEG INSTRUCTIONS: Stand on one leg as long as you can without holding on. ( ) 4 able to lift leg independently and hold > 10 seconds ( ) 3 able to lift leg independently and hold 5-10 seconds ( ) 2 able to lift leg independently and hold 1- 3 seconds ( ) 1 tries to lift leg unable to hold 3 seconds but remains standing independently. ( ) 0 unable to try of needs assist to prevent fall

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