ES FOR MUSCLE CONTRACTION (NMES & FES): INNERVATED M.S

Intact peripheral n. including motor unit & neuromuscular junction

Innervated muscles

Innervated muscles usually manifest as

Disuse atrophy

Ex. of innervated muscles (problems)

Post-op weakness

Orthopedic conditions

CNS affectations

Peripheral n injury can cause

Muscle denervation

Denervated muscles usually manifest as

Denervation atrophy

Use of ES to produce muscle contractions in innervated muscles

NMES (Neuromuscular Electrical Stimulation)

FES (Functional Electrical Stimulation) Is also known as

Orthotic Substitution

Type of NMES that specifically enhances the control of movement and posture

FES

NMES integrates into functional activities

FES

Volitional vs. Electrically-induced: Due to __

Volitional: Due to command from upper motor neurons

Electrically-induced: Due to applied electricity stimuli

Volitional vs. Electrically-induced: Motor units (size)

Volitional: Smaller to larger motor units

Electrically-induced: Larger to smaller motor units

Volitional vs. Electrically-induced: Muscle fibers

Volitional: Activates first type I m. fibers

Electrically-induced: Activates first type II m. fibers

Volitional vs. Electrically-induced: Motor units (Recruitment)

Volitional: Asynchronous

Electrically-induced: Synchronous

Volitional vs. Electrically-induced: Muscle fatigue

Volitional: Slow onset of m. fatigue

Electrically-induced: Rapid onset of m. fatigue

Therapeutic effects

Increase m. strength

Promote m. re-education

Prevents disuse atrophy

Reduces m. spasm

Reduces m. spasticity

Reduces edema

Increased m. strength happens by (4)

Overload principle

Specificity theory

Increased m. size

Improved motor unit recruitment

Inc m. strength: Overload principle

Inc current & frequency, dec pulse duration → increase externally-applied resistance

Inc m. strength: Specificity theory

Targets type II m. fibers (which are reduced aft surgery, immob, or pathology)

Inc m. strength: How long does it take for inc m. mass to occur

Several weeks

Inc m. strength: Motor unit recruitment is improved since it occurs more __ & there is __ recruitment of more motor units

Occurs more rapidly

Synchronized recruitment of more motor units

Promote m. re-education bc it improves __ & stimulates __

Bc it Improves motor control & stimulates brain plasticity

Prevents disuse atrophy

Provides externally-induced m. contraction to prevent m. wasting

Serves as a biofeedback to promote m. contraction (c adequate strength)

To reduce m. spasm, electrodes are over __ to __

Over both agonist

Fatigue the muscle = relaxation

To reduce m. spasticity, electrodes are over __ for __ inhibition & __ to __

Over the agonist - reciprocal inhibition

Over both agonist & antagonist - mimics normal motor activity or typical behavior of indivs s CNS dysfunc

Reduces edema through

muscle pumping effect

When is FES used

During gait training

For idiopathic scoliosis

During gripping activity

For shoulder sublux

During cycling

FES: During gait training

Over tibialis anterior during initial contact

Over gastrocsoleus during push off

FES: For idiopathic scoliosis

Over lateral flexors on convex side

FES: During gripping activity

Over wrist extensors

FES: For shoulder subluxation

Over supraspinatus and pos delts

FES: During cycling

UE: Over biceps brachii and triceps brachii

LE: Over quadriceps femoris & hamstrings

Waveforms

Biphasic pulsed current

Russian current

Interferential current

Biphasic pulsed current

Commonly: square, balanced, symmetrical

some use asymmetrical biphasic PC

Russian current

Uses medium freq AC c freq of 2500 Hz delivered in 50 bursts/sec

Interferential current

Alternating medium-freq currents

Slightly out of phase

amplitude-modulated at low freq

Electrode placement: Active electrodes over __ & dispersive electrodes __

Active electrode over motor point

Dispersive electrode 2-in away on same muscle following orientation of fibers

What is used for the face and smaller m.s of the hand

Motor point stimulation using a probe or motor pen

Bipolar if __, Monopolar if __

Bipolar: same muscle, Large muscle grps

Monopolar: other area, Small m. grps

Where does the motor point occur

bw 2 pads

Most excitable part of the muscle

belly

Closer electrodes =

Farther electrodes =

Superficial

Deep

4 electrodes over muscle

Quadripolar

Wider spacing = __ stimulation

deeper

Parameters: Strengthening: Pulse duration

Smaller muscles: 150-200 usec

Larger muscles: 200-350 usec

Parameters: Strengthening: Amplitude

≥50% MVIC

Maximum tolerated m. contraction

Parameters: Strengthening: Ramp up/down

At least 2s

Parameters: Strengthening: Frequency

Smaller m.s: 20 pps

Larger m.s: 30 pps

Smooth tetanic: 35-50 pps

Greater strengthening: 50-80 pps

Parameters: Strengthening: Duration

10-20 mins (10-20 reps)

Parameters: Strengthening: On time: Off time ratio

1:5 initially → 1:3 → 1:1

10s on: 50s off

Parameters: Endurance

Inc contraction time & dec rest intervals

Parameters: Endurance: Pulse duration

Smaller muscles: 150-200 usec

Larger muscles: 200-350 usec

Parameters: Endurance: Amplitude

25-50% MVIC

Parameters: Endurance: Ramp up/down

At least 2s

Parameters: Endurance: Frequency

30-50pps

Parameters: Endurance: Duration

More reps

Parameters: Endurance: On time: Off time ratio

1:1

Parameters: Spasticity: Motor level: Pulse duration

Smaller muscles: 150-200 usec

Larger muscles: 200-350 usec

Parameters: Spasticity: Motor level: Amplitude

At motor threshold; to visible m. contraction

Parameters: Spasticity: Motor level: Ramp up/down

0.5-3 sec

Parameters: Spasticity: Motor level: Frequency

35-50 pps

Parameters: Spasticity: Motor level: Duration

10-60 min

Parameters: Spasticity: Motor level: On time: Off time ratio

1:1, 3:4

Parameters: Spasticity: Sensory level: Pulse duration

20-100 usec

Parameters: Spasticity: Sensory level: Amplitude

Below motor threshold

Parameters: Spasticity: Sensory level: Ramp up/down

N/A

Parameters: Spasticity: Sensory level: Frequency

80-100 pps

Parameters: Spasticity: Sensory level: Duration

10-60 mins

Parameters: Spasticity: Sensory level: On time: Off time ratio

N/A

Parameters: Muscle spasm (motor level): Pulse duration

Smaller muscles: 150-200 usec

Larger muscles: 200-350 usec

Parameters: Muscle spasm (motor level): Amplitude

At motor threshold; to visible contraction

Parameters: Muscle spasm (motor level): Ramp up/down

At least 1s

Parameters: Muscle spasm (motor level): Frequency

35-50 pps

Parameters: Muscle spasm (motor level): Duration

10-30 mins

Parameters: Muscle spasm (motor level): On time: Off time ratio

1:1

2-5s on: 2-5s off

Parameters: Edema reduction (muscle pump, motor level): Pulse duration

Smaller muscles: 150-200 usec

Larger muscles: 200-350 usec

Parameters: Edema reduction (muscle pump, motor level): Amplitude

At motor threshold; to visible contraction

Parameters: Edema reduction (muscle pump, motor level): Ramp up/down

At least 1s

Parameters: Edema reduction (muscle pump, motor level): Frequency

35-50 pps

Parameters: Edema reduction (muscle pump, motor level): Duration

30 mins

Parameters: Edema reduction (muscle pump, motor level): On time: Off time ratio

1:1

2-5s on: 2-5s off

Duty cycle =

[ON/(ON + OFF)] x 100

Stimulation modes

Synchronous (co-contraction)

Reciprocal

Stimulation: Synchronous

Channels 1&2 produce ON and OFF times together

Stimulation: Reciprocal

While channel 1 is on, channel 2 is off

Progressive training methods

NMES

NMES plus volition

NMES as biofeedback for motion

Progressive training methods: NMES

M. contraction solely relies on electricity

Progressive training methods: NMES plus volition

Contraction produced by both electrical stimulator and the pt

Progressive training methods: NMES as biofeedback for motion

Electricity only serves as feedback for contraction

Evidence on NMES

Recovery of UE function after stroke in subacute stage

FES increased cadence & speed; no significance on other gait parameters

Not effective in pts with CLBP

Documentation: NMES/FES

NMES/FES to <affected muscle> x <pulse frequency> x <pulse duration> x <duty cycle or on & off time> x <treatment duration> to <rationale>