Lecture 50 - Modalities

Question 1

NMES (Neuromuscular Electrical Stimulation) Function

Answer 1

Uses electrical current to stimulate muscle contraction

Question 2

T or F: The nerve fibers closest to the electrode is excited first and the density of currents is greatest closest to the electrode and rapidly diminishes as distance from electrode increases

Answer 2

T

Question 3

What are 5 indications of NMES

Answer 3

1. Prevents atrophy (atrophy)
2. Targets strength (muscle weakness)
3. Spasticity
4. Orthotic Substitution
5. Functional electrical stimulation

Question 4

Is NMES more effective than exercise at preventing muscular atrophy

Answer 4

No, while both increase muscle strength and reduce hospitalization length, only exercise increases functionality

Question 5

T or F: NMES does not increase ROM

Answer 5

F, it does

Question 6

How is spasticity reduced through NMES

Answer 6

Acts as an antagonist through reciprocal inhibition to relax spastic muscles

Question 7

What are 3 areas of the body NMES can help with healing in collaboration with a brace

Answer 7

1. Orthotic substitution - foot drop (tibialis anterior)
2. Scoliosis
3. Shoulder subluxation (middle deltoid)

Question 8

How does NMES aid (3 things) in GAIT (functional electrical stimulation)

Answer 8

1. Improves self esteem
2. Improves blood flow
3. Prevents osteoporosis

Question 9

6 characteristics of slow twitch fibers

Answer 9

Question 10

6 characteristics of fast twitch fibers

Answer 10

Question 11

Describe the strength duration relationship between noxious, motor, sensory and subsensory stimuli

Answer 11

Question 12

Distinguish between rheobase and chronaxie

Answer 12

Rheobase: Minimum intensity necessary to excite a motor response
Chronaxie: Minimum time (pulse duration) required to excite muscle tissue for stimulus at twice rheobase

Question 13

Henneman’s Size Principle

Answer 13

In a voluntary contraction, motor units are recruited from smallest to largest as contraction increases

Question 14

Electrical contraction

Answer 14

As the magnitude of stimulation is increased, larger fibers have lower resistance and more induced current passes into these fibers compared to the smaller fibers (large recruited first)

Question 15

Compare and contrast voluntary contraction compared to electrical stimulation

Answer 15

Question 16

What is important about the location of the electrodes to stimulate contraction (2)

Answer 16

1. Closest nerve fibers to electrode are stimulated first
2. Density of currents is greatest closest to electrodes and diminishes as distance from electrodes increases

Question 17

Describe the frequency of a tetanized contraction

Answer 17

Frequency becomes so rapid that the contraction merges and becomes consistent

Question 18

Bipolar vs monopolar electrode placement

Answer 18

Question 19

Monophasic pulsed current

Answer 19

Question 20

What is monopolar electrode set up and its 3 characteristics

Answer 20

Question 21

Biphasic pulsed current

Answer 21

Question 22

What is the bipolar electrode set up and 3 characteristics

Answer 22

Question 23

Bipolar method (electrode application)

Answer 23

2 electrodes of equal size are placed around the painful site

Question 24

Monopolar Method (electrode application)

Answer 24

The active electrode is placed on the site of pain and the dispersive electrode is placed at another point (proximal at a nerve trunk)

Question 25

To reduce NMES fatigue we need to

Answer 25

1. Minimize frequency (critical fusion frequency)
2. Optimize intensity (surf for motor point and use bipolar set up)
3. Have on/off time ratio at 1:3 (off time should be 60 seconds between each contraction)

Question 26

Process of using NMES (5)

Answer 26

1. Perform assessment and determine if NMES is appropriate
2. Clear contraindications (electrical current and muscle activation)
3. Decide on muscles to be stimulated and motor points
4. Set parameters (duration = 250-300 usec; frequency: As low as possible)
5. Decide between monopolar (small muscles) or bipolar placement (large muscles)