EMG Biofeedback Flashcards Preview

Phys Agents > EMG Biofeedback > Flashcards

Flashcards in EMG Biofeedback Deck (48):
1

What is EMG biofeedback

The therapeutic use of instrumentation to detect and feedback electric signals from motor unit action potentials (MUAP) that are generated by active muscle

2

What happens to the MUAP signals

They are detected, amplified, rectified, filtered, intergrated, and converted into audiovisual signals

3

What are the audiovisual signals used for

Reinforce voluntary muscle control

4

True or False:
EMG biodfeedback machines measure actual direct physiologic events

False

5

What does EMG biofeedback actually measure

Some aspect that is highly correlated with an actual physiologic event

6

What are 3 examples of correlated aspects

1. Peripheral skin temperature
2. Finger photo transmission
3. Electromyography

7

A muscle contraction is a result of what

Depolarization of muscle fibers due to binding of NT released from the alpha motor neuron

8

What does the depolarization of the muscle fibers result in

Increased permeability of the muscle membrane to K+ and Na+

9

What does the change in permeability cause

Changes in the concentration of these ions in the extracellular fluid

10

How are these changes in concentrations of ions detected

By surface electrodes connected to a very sensitive voltage measuring device

11

What measures the change in voltage

EMG

12

What is electromyography activity

Changes in the electrochemical gradient created by the MUAP that is detected by an electrode

13

What happens as more motor units are recruited

Muscle tension increases and more electrical activity is detected by the EMG electrode

14

What size motor units are recruited first

Small motor units

15

What do faster contractions tend to do

Excite larger motor units and depress smaller ones

16

What is the firing rate and recruitment of motor units dependent on

The external force required to perform a task successfully

17

What does the amplitude of the EMG reflect (5)

1. Size of motor units
2. Number of active motor units
3. Distance of active muscle fibers from recording electrode
4. Size of recording area
5. Interelectrode spacing

18

True or False:
EMG has near linear relationship with force produced during carefully controlled isometric contractions

True

19

Does the linear relationship hold true for concentric or eccentric contractions

Nope

20

What is electrical activity of a muscle measured in

Micro volts

21

True or False:
Noise must be eliminated before amplification of the detected MUAP can occur

True

22

What can noise be defined as

Extraneous electrical activity that may be produced by any source other than the contracting muscle

23

How many electrodes are required to eliminate noise

3

24

What are the 3 electrodes

2 active electrodes and one reference or ground electrode

25

Where are the active electrodes placed in relationship to each other

Close to one another

26

Where is the reference electrode located

Anywhere in the body

27

What do the active electrodes detect

Electrical activity from the motor units firing in the muscle below them

28

True or False:
The magnitude of the voltage picked up by each electrode differ with respect to the reference electrode

True

29

What happens to the 2 resulting signals

The signal from one active electrode is subtracted from the other leaving only the amplified difference in signals

30

What does the differential amplification do

Significantly decreases extraneous noise

31

What is the ability of the differential amplifer to eliminate common noise between the two active electrodes called

The common mode rejection ratio (CMRR)

32

What happens once the signal is amplified

Any remaining noise in the resultant signal is filtered

33

What is the resulting amplified and filtered signal known as

Raw activity

34

What is the raw activity defined as

An alternating voltage representative of the true electrical activity in the muscle being monitored

35

True or False:
EMG-B units measure the overall increase and decrease in electrical activity so the raw activity must be rectified

True

36

How is the raw activity rectified

By flipping all of the negatively deflected signals upward toward the positive pole

37

What happens after the signal is rectified

It is smoothed and intergrated

38

What is the purpose of EMG-B (2)

1. Change MUAPs into auditory and/or visual cues for the purpose of increasing or decreasing voluntary muscle activity
2. To enhance motor learning by providing feedback about performance until motor skills develop sufficiently so that feed back is no longer needed

39

What are the advantages of EMG-B (3)

1. Provides immediate reward for performance changes that may be too small to note without EMG-B
2. The small changes seen by EMG-B often lead to larger changes in performance improvement
3. Patient is able to obtain feedback about performance without the constant supervision of the therapist

40

What are the indications for EMG-B for motor recruitment

When the goal is to increase the EMG signal from the target muscle

41

What are the indications for EMG-B for motor inhibition

When the goal is to decrease the EMG signal from the target muscle

42

What are the indications for EMG-B for total body relaxation

Conditions of generalized pain or stress where the goal is to decrease undesirable muscle tension to achieve muscle relaxation and stress reduction

43

What is an example of when you would use EMG-B to increase the EMG signal from the target muscle

A muscle that is hypoactive

44

What is an example of when you would use EMG-B to decrease the EMG signal from the target muscle

A muscle that is hyperactive

45

What are the contraindications of EMG-B

Any condition where muscular contraction might exacerbate the condition

46

When using EMG-B how must you clean the skin

By using alcohol

47

True or False:
You want the active electrodes to be parallel to the muscle fibers

True

48

Where do you put the ground electrode

Over a boney prominence or non contractile tissue