Neuromuscular Electrical Stimulation

Question 1

Neuromuscular electrical stimulation (NMES)

Answer 1

Type of pulsed, alternating current used to stimulate a motor response by depolarizing intact peripheral nerves
Intact peripheral nerve and healthy muscle tissue is required for activation

Question 2

Current flow parameters

Answer 2

Unipolar: Current flows in one direction
Bipolar: Current flows in two directions

Question 3

Pulse frequency

Answer 3

Number of pulses per second (pps) or Hertz (Hz)

Question 4

Recommended frequency range for NMES

Answer 4

30-75 Hz to facilitate increased firing rate and cause tetanic reaction
35 Hz for otherwise healthy patients
50 Hz to fatigue spastic muscles

Question 5

Cycle frequency

Answer 5

Number of cycles completed per second (cps)

Question 6

Pulse duration (pulse width)

Answer 6

Length of time electrical flow is on for one cycle to take place
Measured in microseconds
Determine which nerve fibers are preferentially recruited

Question 7

Pulse width of 20-100 microseconds

Answer 7

Preferentially recruits sensory nerves
Large diamter A-beta nerve fibers that are hyper-stimulated to override pain

Question 8

Pulse width of 200-400 microseconds

Answer 8

Preferntially recruits motor nerves
Recruits large diameter A-alpha motor nerves necessary for muscle contraction

Question 9

Pulse width of 400-1000 miscroseconds

Answer 9

Preferentially recruits pain-carrying nerve fibers
Used in noxious electrotherapy protocols
Concept of pain relieving pain

Question 10

Pulse amplitude

Answer 10

Strength of current measured in milliamps
Associated with the depth of penetration (deeper penetration will result in more muscle fiber recruitment)
Amplitude needs to be 25-50 milliamps to make a muscle contract

Question 11

Pulse amplitude for cardiac arrest

Answer 11

75 milliamps

Question 12

Peak amplitude

Answer 12

Maximum amount of voltage delivered in a single phase

Question 13

Pulse charge

Answer 13

Number of electrons contained within a pulse

Question 14

Pulse rise time

Answer 14

Time needed for pulse to reach its peak value for nerve depolarization

Question 15

Pulse decay time

Answer 15

Time required or pulse to go from its peak back to zero

Question 16

Pulse train

Answer 16

Individual patterns of waveforms, durations, and/or frequencies that are linked together and repeated at regular intervals

Question 17

Amplitude ramp

Answer 17

Gradual rise or fall in the amplitude of a pulse train
2 second ramp up time is effective for non-spastic muscles
6-8 second ramp up time is helpful for mild to moderate spasticity

Question 18

On/off cycle for strengthening

Answer 18

May require starting at 1:3 time ratio and progressing to 1:1 time ratio

Question 19

On/off cycle for muscle reeducation

Answer 19

May require starting at a 1:3 time ratio and progress to 1:5 time ratio

Question 20

Purposes of NMES

Answer 20

Improve muscle strength without increasing cardiovascular output
Enhancing range of motion
- Provides regular stretching over an extended period of time
Inhibit spasticity or muscle spasms
- Reciprocal stimulation of agonist and antagonist pairs can reduce spasticity
- Stimulate spastic agonist to fatigue
Strengthen muscles
- Increases muscle bulk
Improves capillary density in muscles
- Improves local blood supply
- Facilitates microcirculation
Improve endurance
Muscle reeducation or neuromuscular facilitation
- Ask patient to try and assist the action of the stimulator with voluntary movement
Reduce pain/temporarily correct shoulder spasticity/subluxation
- Can improve the resting position of joints
- Stimulation of posterior deltoid and supraspinatus as a substitute for traditional arm slings
- Modulate pain due to neurotransmitters and increase of endogenous opiates
Initiate orthotic substitution
Control edema
Enhance effect of botulinum toxin
- Botox can be more easily absorbed if muscles are active
Take up occurs over first two days after injection

Question 21

Neuromuscular reeducation treatment protocol for NMES

Answer 21

Use goal-directed activity along with NMES to increase motivation, proprioceptive and kinesthetic feedback, and increase neural plasticity
Start with patient achieving tetanic muscle contraction
Progress to muscle fasciculation to cue patients to contract muscle

Question 22

NMES Strengthening protocol

Answer 22

Increase amplitude to about half of individuals maximum isometric muscle contraction

Question 23

NMES precautions

Answer 23

Use lowest effective current on patients with impaired mentation or sensation
Monitor motor response and skin
Areas of irritation, damage, or skin lesion can cause decreased tissue impedance and increased current tha tmay result in pain
Fractures
Pregnancy
Allergy or skin sensitivity

Question 24

NMES contraindications

Answer 24

Lower back or uterus during first trimester of pregnacy
Metastases
Osteomyelitis
Thrombosis
Allergy to iontophoretically-derived medication
Patients who are taking diuretics
Should not be applied to craniofacial or cervical region of patient with history of CVA or seizures
Over phrenic nerve or bladder stimulators
Over carotid sinus
Near diathermy devices (minimum 9’ clearance)
Over or near superficial metal pins, plates, or hardware
Patients with cancer, infection, tuberculosis, or active hemorrhage
Cardiac pacemakers

Question 25

NMES for neurologically impaired patients

Answer 25

Extend ramp-up time to at least 6 to 8 seconds to ensure blocking of undesirable motor patterns
Consider serial casting or splinting

Question 26

Brunnstrom’s Stages of Recovery

Answer 26

Stage 1: Flaccidity
Stage 2: Spasticity appearance
Stage 3: Increased spasticity
Stage 4: Decrease spasticity
Stage 5: Complex movement combinations
Stage 6: Spasticity disappears
Stage 7: Normal function returns

Question 27

Tenolysis of hand

Answer 27

Procedure used to remove adhesions from tendons and is designed to improve active digital movement into flexion or extension
Place electrodes over wrist and finger flexor muscles or wrist and finger extensor muscles

Question 28

Dual channel shoulder subluxation parameters

Answer 28

Black electrode over posterior deltoid; red over supraspinatus
Black over middle deltoid; red over anterior deltoid

Question 29

Mass upper extremity extension (shoulder flexion, triceps, and wrist extension)

Answer 29

Black over anterior deltoid; red over supraspinatus
Black over wrist extensor muscle near lateral epicondyle; red over mid-triceps

Question 30

Hand to mouth pattern (biceps and shoulder elevation)

Answer 30

Black is over anterior deltoid; red over supraspinatus (or middle deltoid)
Black is over belly of biceps; red is over forearm extensors (fleshy part near lateral epicondyle)

Question 31

Forearm/hand pumping pattern (wrist flexion/extension)

Answer 31

Black over wrist extensor belly near lateral epicondyle; red is over the extensor tendons on the mid forearm
Black is over the flexor muscle belly near medial epicondyle; red is over flexor tendons on mid forearm

Question 32

Wrist extension

Answer 32

Black is over wrist extensor belly near lateral epicondyle; red is over extensor tendons on mid forearm

Question 33

Wrist flexion

Answer 33

Black is over the flexor muscle belly near medial epicondyle; red is over flexor tendons on mid forearm

Question 34

Triceps extension

Answer 34

Black over triceps; red is over olecranon insertion

Question 35

Biceps flexion (hand to mouth pattern with one channel)

Answer 35

Black is on mid-biceps; red is distal to biceps near tendon

Question 36

Shoulder abduction

Answer 36

Black is on middle deltoid; red is on supraspinatus

Question 37

Shoulder flexion

Answer 37

Black is on anterior deltoid; red is on suprasintus/upper trapezius

Question 38

Shoulder approximation (single channel options)

Answer 38

Black is on anterior deltoid; red is on posterior deltoid

OR

Black is over posterior deltoid; red is over supraspinatus