FES & Biofeedback

common uses for FES

Foot-Drop (orthotic)

Shoulder Subluxation (orthotic)

Standing Function (orthotic & training)

Locomotor training

Hand-Grasp Function (orthotic & training)

Bowel & Bladder Function

considerations for FES

Sensation/Skin integrity

Autonomic Dysreflexia (SCI)

Joint-integrity, Intact PNS

Muscle Strength & Endurance

Cognitive ability, Support system

FES frequency; Lower pps for FES

20-60pps

Moderately strong contraction

**FES phase duration: Muscular we will have a pulse or phase duration between

200-400 microsec (~250, can drop if uncomfy)

FES total tx time

30 mins- 6 hours

FES ramp time

1 second

FES Set up: Hemiplegia – shoulder subluxation; muscles that are targeted

Supraspinatus

Posterior & Middle deltoid: (w/ anterior deltoid possible shoulder flexion may occur)

Hemiplegia – shoulder subluxation sulcus sign

gap between GH jt

FES parameters: Hemiplegia – shoulder subluxation length of tx

30min to 6 hours; 5-7 days/week

On:Off for endurance 10:12, 30:2, 15:15

FES SET UP: Reaching tasks, Electrodes are placed over what is necessary

Scapular stabilizer

Deltoid (shoulder abduction)

Triceps (elbow extension)

Wrist extensors (wrist extension)

FES SET up: gait training Common impairments

Foot drop

Decrease PF strength, poor push-off

SET up: gait training factors

Combo w/ Treadmill training

Unit used in clinic

Unit use has a functional brace

Switch controlled in shoe or trigger controlled by therapist.

what is a recording voltage changes as muscle membrane depolarizes?

Myoelectric signal

we use EMG biofeedback in the clinic to

increase activity level or muscle output (re-education)

decrease muscle activity (muscle spam/pain/spasticity)

advantages of EMG feedback

sensitive: small changes in recruitment

objective: measure in microvolts

speed & continuity: accurate/quantitative in nature

relational: show which efforts create more recruitment, shift locus of control

disadvantages of biofeedback

Signal not related to just muscle force

A local recording: We don’t work in single muscle actions

Useful for superficial muscles, not deep

May pick up recording from other muscles: Cross talk

amplitude of EMG signal reflects the

# muscle cells locally depolarizing via Recruitment & Rate coding

#fibers/motor units/motor neurons/size

distance of active motor units from recording electrodes

related to isometric force

what alters the EMG signal?

Recruitment: Level of effort, Type of contraction, Motor learning, Fatigue

Artifact: Motion (10 Hz), Noise (60 Hz, 500Hz), Cross-talk

Electrodes: Size, Distance between electrodes (1 cm (commonly used) or > distance >recording area < specificity), Distance from muscle monitoring, Movement, Relationship to other active muscles (cross talk), Quality, Skin quality

Biofeedback selection of pt must have increased or decreased motor impairment, voluntary control, able to process

feedback & see/hear signal

Cognitively able to utilize feedback

Some evidence more effective 20-35yo than 55-70yo

in a foot drop pt, make sure they have their

shoes on for FES

for foot drop pt, assess the amplitude by

have them seated at edge of plinth, increase amplitude until strong enough contraction to dorsiflex

for a fall risk pt with FES, contact guard on

side of impairment