WK6- NMES, FES, EMS

Question 1

What are the differences between NMES, FES, and EMS

Answer 1

NMES: activation of skeletal muscle for strengthening, re-education or edema reduction; depolarization of peripheral nerve to create a muscle contraction

FES: activation of skeletal muscle for functional usage, may be used on innervated or denervated muscle

EMS: implies the stimulation of denervated muscle

Question 2

What is the primary difference between NMES and EMS ?

Answer 2

The type of tissue stimulated

NMES stimulates nervous tissue, EMS aims to simulate muscle tissue

Question 3

When the neural system is intact distally what ES options are recommended? When the neural system is not intact what ES option should you consider ?

Answer 3

NMES and FES

EMS

Question 4

Define NCS and EMG

Answer 4

NCS= nerve conduction study that assess motor and sensory nerve function using surface electrodes

EMG: electromyography study that looks at the integrity of muscle/nerve complex.

Question 5

What are the general goals of using NMES for strengthening and re-education ?

Answer 5

prevent or treat muscular atrophy following disuse, immobilization, or detaining

increase or maintain ROM

re-education, retrain, or facilitate muscle for movement or posture.

Question 6

True or False. There poor to moderate evidence supporting NMES use for strengthening of weakened muscle.

Answer 6

False. NMES has been proven to increase muscle size and motor unit recruitment

Question 7

What other conditions have been shown to benefit from NMES?

Answer 7

Post Knee surgery: ACL, TKA, knee ligament and meniscal tears, best when used early in rehab

Knee OA, PFS, atrophy associated with RA

COPD, heart failure, thoracic cancer, cardiothoracic surgery

Question 8

What is the evidence for NMES for strengthening in neurological poplulations ?

Answer 8

stroke, cerebral palsy, SCI, MS studied

best evidence for stroke

enhances strength, ROM, and function

Question 9

How does NMES increase ROM in neurologic populations?

Answer 9

stimulation of antagonist leads to increased length of agonist

Question 10

What are the three theories for the usage of NMES for treatment of spasticity?

Answer 10

spasticity is velocity dependent increase in tone ( UMN)

1. stimulate antagonist- NMES applied to the antagonist muscle decreases spasticity through reciprocal inhibition of the spastic agonist muscle. It occurs through inhibitory interneurons with in the spinal cord.
2. stimulate agonist- NMES applied to the spastic agonist muscle works by fatiguing the muscle or by providing recurrent inhibition via Renshaw cells which when stimulated inhibit the spastic muscle cell.
3. habituation of sensory input- ES when delivered only at sensory levels leads to sensory habituation that then leads to a decrease in spasticity

Question 11

What are the specific precautions of implanted sacral stimulators for urinary incontinence ?

Answer 11

pregnancy or planning to be pregnant, infections or lesions, prolapsed uterus, recent pelvic surgery

Question 12

What is the correct placement of the electrodes for NMES ?

Answer 12

One electrode goes directly over the muscle to be stimulated and one over its motor point running parallel to the muscles fibers.

may need to be adjusted for desired effect.

Question 13

What are the 3 common waveforms used for NMES ?

Answer 13

Pulsed Bi-phasic, Russian, Aussie

Question 14

What is the general rule when choosing an amplitude ?

Answer 14

highest tolerated pulse duration/ amplitude but ideally should meet or exceed 50% of max volitional contraction

Question 15

What is the common frequency used in NMES ?

Answer 15

30pps or 20-30 for small muscles

Question 16

When using NMES for the reduction of spasm and increase of ROM what is the recommended on and off time ?

Answer 16

1:1 ratio

Question 17

When using NMES for strengthening what is the recommended duty cycle/ on and off time ?

Answer 17

10% to 50% duty cycle

1:5
1:3

Question 18

What are the parameters for NMES and FES with the goal of muscle strengthening. Include waveform, pulse frequency, pulse duration in microseconds, amplitude, duty cycle, duration.

Answer 18

Goal: Muscle Strengthening

Type: NMES

Waveform: Biphasic PC or burst modulation ( Russian or Aussie)

Pulse Frequency: 20-80 pps depending on muscle size

Pulse Duration: 200-600 microseconds depending on muscle size

Amplitude: As high as tolerated while reaching 50% MVC

Duty Cycle: 1:3, 1:5 with on-time up to 10sec off and time up to 50 sec

Duration:10-20 strong contractions o rup to 1hr/day, 3-5x/week, 4-8 weeks

Question 19

What are the parameters for NMES and FES with the goal of muscle spasm reduction or improvement of tissue extensibility. Include waveform, pulse frequency, pulse duration in microseconds, amplitude, duty cycle, duration.

Answer 19

Goal: Tissue extensibility/ - muscle spasm

Type: NMES

Waveform:Biphasic PC or burst modulation ( Russian or Aussie)

Pulse Frequency: 35-50 pps

Pulse Duration: 125-250 microseconds depending on muscle size

Amplitude: to visible contraction

Duty Cycle: 1:1, ramp up and down 1-5 sec

Duration: 10-30 min, 1-4x/week, 2 weeks-6 months

Question 20

What are the parameters for NMES and FES with the goal of muscle contraction for functional use. Include waveform, pulse frequency, pulse duration in microseconds, amplitude, duty cycle, duration.

Answer 20

Goal: Muscle contraction for functional use

Type: FES

Waveform:Biphasic PC or burst modulation ( Russian or Aussie)

Pulse Frequency: 20-60 pps

Pulse Duration: 200-600 microseconds depending on muscle size

Amplitude: matching functional usage

Duty Cycle: depends on activity

Duration: task specific

Question 21

What is the difference in motor unit recruitment when done volitionally compared to NMES.

Answer 21

normally the body recruits small type I fibers which take longer to fatigue, however motor recruitment is random in NMES and therefore can lead to faster fatigue and increase DOMS

Question 22

True or False. Line powered simulators are recommended over battery powered NMES machines.

Answer 22

True.

Question 23

How can NMES help reduce swelling associated with edema ?

Answer 23

repetitive muscle contractions compress veins and lymph vessels, reduce swelling and increase venous and lymphatic return using a symmetrical or asymmetrical biphasic PC or Russian current.

Question 24

What are the NMES parameters for subacute and chronic edema management ?

Answer 24

Type: NMES

Waveform: biphasic PC or Russian or Aussie

Pulse Frequency: 20-80 pps

Pulse Duration: 100-600 microseconds

Amplitude: mA to tetanic contraction

Duty Cycle: 1:1 on: off ratio, on 2-5 seconds, off 2-5 seconds, equal on: off times: 1 sec ramp up and down time.

Duration: 10-20 minutes of rhythmic contractions, 1-2x/day, monitor edema

Question 25

What are the general recommendations of EMS for denervated muscle ?

Answer 25

long pulse durations, higher intensity, Direct current

Question 26

What are the parameters for EMS usage for denervated muscle?

Answer 26

Pulse Duration: 1-450msec
Frequency: 1-500pps
Amplitude: high enough to obtain contractions but low enough to prevent burns
Ramp up and down time: not specified
Duty cycle: Variable, on time 3-10 sec and off time 30-50 seconds
Treatment time and duration: 30 min/8 hours per day; 5-7 days/week; 4 days to 4 years