NMES

Question 1

How is NMES initiated?

Answer 1

With the excitation of peripheral nervous tissue

Question 2

Definition: defines the LOWEST level of electrical charge that generates an action potential

Answer 2

stimulus threshold

Question 3

definition: phenomenon of the action potential produced by natural physiologic means is identical to the action potential induced by NMES

Answer 3

all or none phenomenon

Question 4

(true/false) You can have a peripheral lesion and still use NMES

Answer 4

FALSE – MUST have an intact LMN

Question 5

The threshold for eliciting a nerve fiber action potential is (less/more) than the threshold for muscle fiber stimulation.

Answer 5

LESS (100-1000x less)

Question 6

(true/false) Clinical NMES systems stimulate either the nerve directly or the motor point of the nerve proximal to the neuromuscular junction

Answer 6

true

Question 7

definition: The most electrically excitable area of the muscle wherein a minimum amount of electrical stimulation will easily excite this portion of the muscle

Answer 7

motor point

Question 8

What principle does nerve fiber recruitment mediated by NMES follow?

Answer 8

Reverse recruitment order

Question 9

The nerve stimulus threshold with the principle of reverse recruitment order used with NMES (is/is not) inversely proportional to the diameter of the neuron

Answer 9

It is

–> Larger fibers that innervate larger motor units are recruited first

Question 10

(true/false) The nerve fiber recruitment properties elicited by NMES differ from those elicited by normal physiologic means

Answer 10

true

Question 11

An action potential produced by normal physiologic mechanisms initially recruits the (smaller/larger) diameter neurons prior to recruitment of the other.

Answer 11

smaller diameter neurons

Question 12

Alpha motor neurons are (small/large) fibers

Answer 12

large fibers

Question 13

Type ___ fiber:
- smaller motor units
- low forces
- resistant to fatigue

Answer 13

type I

Question 14

Type ___ fibers:
- larger motor units
- higher force
- rapidly fatigue

Answer 14

Type II

Question 15

What is NMES dependent on?

Answer 15

An intact (alpha) low motor neuron

Question 16

Clinical application of NMES is presently limited to neurologic injuries involving (UMN/LMN.

Answer 16

UMN

Question 17

Several studies document the therapeutic benefit of electrical stimulation on muscle-fiber regeneration in _____ denervation

Answer 17

LMN degeneration

Question 18

What determines the numbers of muscle fibers recruited when using NMES?

Answer 18

amplitude and pulse width

Question 19

What is the minimum stimulus frequency that generates a fused muscle response?

Answer 19

12.5 Hz

Question 20

What is the result of higher stimulus frequencies?

Answer 20

generate higher forces but result in fatigue and decreased contractile force of a muscle

Question 21

An optimal NMES system utilizes the (minimal/maximal) stimulus frequency that produces a fused response and not just “twitching”

Answer 21

minimal stimulus frequency

Question 22

What is the ideal stimulation frequency range for UEs?

Answer 22

12-16 Hz

Question 23

What is the ideal stimulation frequency range for LEs?

Answer 23

18-25 Hz

Question 24

What is the frequency range for NMES units?

Answer 24

10-50 Hz

Question 25

NMES is delivered as a waveform of electrical current characterized by what?

Answer 25

1. stimulus frequency 2. amplitude 3. pulse width

Question 26

Temporal summation is determined by what?

Answer 26

the rate at which stimulus pulses are applied to muscle

Question 27

How does temporal (wave) summation occur?

Answer 27

Occurs if consecutive stimuli are applied during the relaxation period of each preceding muscle contraction. In this case, each subsequent contraction builds upon the previous contraction before its relaxation period ends.

Question 28

definition: occurs when the frequency of stimuli increases and successive muscle contractions begin to blend, almost appearing as a single large contraction.

Answer 28

incomplete tetanus (unfused tetanus)

Question 29

definition: occurs when the frequency of stimuli increases further. In this case, individual muscle contractions completely fuse to produce one large muscle contraction.

Answer 29

complete tetanus (fused tetanus)

Question 30

(true/false) The optimal pulse frequency for a muscle contraction is one that produces a “fused” response without discomfort

Answer 30

true

Question 31

Why is clinical application of NMES complicated?

Answer 31

1. the contractile force of muscle is variable over time 2. muscle force generation is impacted by multiple factors distinct from the stimulation parameters of the NMES system

Question 32

(true/false) NMES can activate paralyzed muscles in precise sequence and magnitude to accomplish functional tasks

Answer 32

true

Question 33

definition: An artificial system bypassing the neural system to restore lost body functions by providing functional movement patterns using electrical stimulation.

Answer 33

neural prosthesis ex: drop foot

Question 34

definition: Changing normal and abnormal neural activity in both sensory and motor nerves to manipulate function (pain, neural plasticity)

Answer 34

neuromodulation --> most common neuromodulation treatment is spinal cord stimulation for chronic neuropathic pain

Question 35

What is the indication for NMES?

Answer 35

UMN lesions

Question 36

What warrants precautions when using NMES?

Answer 36

- impaired sensation - edema (can interfere with adequate stimulation)

Question 37

What are contraindications for NMES?

Answer 37

- healing FX - wounds - pacemaker - malignancy or phlebitis in the treatment area - superficial metal implants

Question 38

Electromyographic findings of muscle dysfunction can occur within _______ IF they are cosncious.

Answer 38

a few days

Question 39

Electromyographic findings of muscle dysfunction would take ______ IF the person is unconscious.

Answer 39

3 weeks

Question 40

(true/false) Electronic equipment such as ECG monitors and alarms may not operate properly when TENS/NMES in use

Answer 40

true

Question 41

DO NOT use ______ to assist paraplegic patients into the standing position

Answer 41

FES

Question 42

What is the electrode placement for shoulder subluxation?

Answer 42

Negative/black: proximal 1/3 over posterior deltoid Positive/red: superior to the spine of the scapula (critical to prevent the activation of the upper trapezius muscle)

Question 43

When placing electrodes, select the (smallest/largest) possible electrode that minimizes overflow to other muscles and conforms to the treatment area

Answer 43

largest electrode

Question 44

How should muscular fatigue be measured with NMES for shoulder subluxation?

Answer 44

by palpating the amount of subluxation present at the end of the stimulation session

Question 45

What is the NMES electrode placement for gait training?

Answer 45

Negative/black: over anterior tibialis slightly overlapping the peroneous longus Positive/red: distal mid-lower leg over the peroneal muscles and tendons

Question 46

What is the goal of NMES use while gait training?

Answer 46

facilitate DF without excessive inversion and eversion

Question 47

What is the electrode placement for finger EXT when using NMES?

Answer 47

Negative/black: over motor point of muscle mass most likely to produce finger EXT without activating wrist EXT Positive/red: distal aspect of extensor muscle belly

Question 48

(true/false) There is an on-off cycle when using a hand-triggered switch

Answer 48

FALSE (there is not)

Question 49

How is a heel switch triggered with NMES during gait training?

Answer 49

heel strike

Question 50

What does an asymmetrical waveform do?

Answer 50

Allows the negative electrode to be more active