FES for Musculoskeletal and Neuromuscular Disorders

Neuromuscular electrical stimulation (NMES)

• “The use of electrical stimulation to activate muscles through stimulation of an intact peripheral nerve”

• Goal: strengthening of muscles; generating muscle contractions leading to improved motor control

Functional electrical stimulation (FES)

• “The use of NMES to promote functional activities”

• Goal: enhancing function; stimulating muscles for specific movements leading to improved motor learning

General Applications Evidence Review (Nussbaum, 2017)

Critical review and practice recommendations cite moderate to strong evidence for NMES or FES as a tx for

• SCI

• UE/LE post stroke

• Weakness post ACL repair and TKA

• Weakness in knee OA

• Debilitation and weakness after critical illnesses

Musculoskeletal applications

• Strengthening

• Recovery

• Fractures

• Immobilization periods

• Muscle/joint stiffness or ROM

• Function

MSK Applications

• NMES post ACL reconstruction:

  • Positive benefits on increased strength and improved gait pattern when NMES was used post surgery compared to voluntary exercise alone

  • “maximum tolerated” stimulation was used

• NMES post TKA

  • NMES for 6 weeks post TKA led to better strength and function at 1 year compared to standard rehab

• NMES for ROM improvements

  • Achieves repetitive motion of the shortened muscle by stimulating the antagonist

NMES post ACL reconstruction:

Positive benefits on increased strength and improved gait pattern when NMES was used post surgery compared to voluntary exercise alone

“maximum tolerated” stimulation was used

NMES post TKA

NMES for 6 weeks post TKA led to better strength and function at 1 year compared to standard rehab

NMES for ROM improvements

Achieves repetitive motion of the shortened muscle by stimulating the antagonist

FES Use Cases

Used when traditional exercise or rehab is difficult

• ICU

• Severe mobility restrictions or deconditioning

• Poor muscle activation without adjunctive NMES

• Chronic conditions

Applications in Critical Illness

• A systematic review by Mufietti comparing NMES to “usual care”:

  • Increased or better preservation of strength with NMES (5 studies)

  • Muscle Mass:

    • No significant changes in muscle thickness (2 studies)

    • Better preservation of muscle mass (2 studies)

• Overall conclusion: NMES + usual care is more effective than usual care or sham in preventing ICU associated weakness, but there is inconclusive evidence about its effect on preservation of muscle mass.

• Also positive effective on pulmonary function, physical function, and reducing incidence of critical illness polyneuromyopathy

Neuro Specific Applications of NMES/FES

• Restoring function

• Neuromuscular re-education

• Increase strength

• Facilitate movement

• Prevent or reverse disuse atrophy

• Maintain or increased ROM

• Increase local blood circulation

• Cardiorespiratory fitness

• Managing paralysis

• Managing dysphagia (ST)

• Reduce spasms and spasticity

• Orthotic substitution

• Shoulder subluxation

• Others…?

FES

FES = NMES in function

Sky is the limit for activities

FES in Shoulder Subluxation

• Combined with proper positioning, slings, and other therapy

• Research supported for its role in reducing sublux in acute stroke but not chronic

  • Mixed results on pain and ROM

• More favorable outcomes seen in acute stroke and in those with hemiparesis as opposed to hemiplegia

FES in Shoulder Subluxation- Electrode Placement

• Common placement: posterior deltoid and supraspinatus

  • Avoid upper trap placement

• Alternative is two channels:

  • One stimulating ant and post delt and the other stimulating middle delt and supraspinatus

• May consider concurrent scapular retraction stimulation

FES for Hand and UE Function

• H200- orthosis for functional grasp

  • Improved ROM, functional grasp, spasticity

• Need proximal strength for proper operation of hand device

• Continuous reliance vs ability to transition away from device

FES orthotic substitution

• Assist with DF during swing phase

• Maintain slight ant tib translation during mid to terminal stance

• Check for sufficient PROM when determining expected effects

• Alternative to AFO

• May combine with treadmill training for intensity of training effect

Evidence for FES Orthosis

Improved:

• Dorsiflexion during swing

• Walking speed

• TUG

• Gait symmetry

• Walking endurance

• Social integration, QOL

• Decreased physiologic cost of walking

• Muscle size

FES for Orthotic Substitution- Bioness

• Original models: stimulation timing controlled by heel switch

• Alternative models: controlled by angle of tibial incline

• Optional quad and hamstring cuff

• Electrode placement is key

CPG on AFO and FES Post Stroke (Johnston, 2021)

• “Strong evidence exists that AFO and FES can each increase gait speed, mobility, and dynamic balance.”

• “Moderate evidence exists that AFO and FES increase quality of life, walking endurance, and muscle activation

• “Weak evidence exists for improving gait kinematics.”

• “AFO or FES should not be used to decrease plantarflexor spasticity.”

• “Studies that directly compare AFO and FES do not indicate overall superiority of one over the other. But evidence suggests that AFO may lead to more compensatory effects while FES may lead to more therapeutic effects.”

FES Cycling

• Cyclical stimulation to LE muscles

  • Quads/hams/glutes

  • 12 channel systems allow addition of ant tib/gastroc/erectors

• Improvements in:

  • Muscle volume, fiber size

  • Fat free tissue

  • Bone density

  • Cardiovascular health

  • Circulation

  • Reduce spasticity

  • ROM

• Optimal dose is at least 3x/wk, 30-60 min

• Beneficial at early stages and for lifelong fitness

RT300 cycle is FDA cleared to

• Prevent muscle atrophy

• Relax muscle spasms

• Improve local blood circulation

• Maintain or increase range of motion

• Facilitate muscle re-education

SCI (van der Scheer, 2021)

• Systematic Review of 92 studies of 999 adults with SCI

• Looked at effects of FES cycling

• Significant improvements on the following were found in ¾ level 1-2 studies and 27/32 level 3-4 studies

  • Muscle health (muscle mass, fiber type composition)

  • Power output and aerobic fitness (peak power and oxygen uptake)

FES in Other Contexts for LE Function (Rahimi, 2020)

• RCT evaluating WB mat exercises with/without FES to quads and gastroc on ability to transfer and gain ADL independence

• 16 chronic paraplegics

• Primary outcome was SCIM-III which reflects independence with ADL’s and transfers

• Mat based WB exercises + FES showed greater improvements than mat based WB exercises alone

Stimulation Based on EMG Pattern of Activity

• Xcite library of exercises

• STS

• Toe taps

• Heel slides

• Bridges

• Transfers

• Planks

• Standing WB

Stroke

FES + therapy improved UE motor function and ADL’s compared to therapy alone (Nadeau 2017)

FES moderately enhances walking speed and UE activity compared to no intervention or training /s FES (McHugh 2015)

SCI

FES + PT improved gait speed compared to conventional therapy (Fouad, 2021)

FES cycling post SCI led to improved cardiovascular fitness, muscle strength, and metabolic health. (Hamzaid, 2021)

Heart failure

LE FES improved cardiopulmonary function and QOL (Papadopoulos, 2024)

FES on Spasticity

• Theories:

  • NMES to antagonist muscle decreases spasticity through reciprocal inhibition of spastic muscle.

  • NMES to agonist muscle fatigues the muscle by providing recurrent inhibition

  • Sensory only e-stim can cause habituation and lead to dec spasticity

• Lengthen the ramp time if stimulating antagonist

• Keep amplitude sub-tetanic if stimulating agonist

• Stimulate agonist continuously and at higher frequencies (90-100 Hz)

SR (Fang, 2021) on FES in SCI

• Spasticity decreased significantly with FES training (p=0.013)

• The significant decrease was only noted in more than 20 training sessions (p=0.02)

• Also showed improvements in walking ability (6MWT, TUG) and LE strength

• Short lived, transient effects

  • Pharmacologic intervention still best

FES on Unilateral Neglect

• Case series (Harding, 2009) applied FES to L forearm and measured results up to 6 months

  • Saw reduced symptoms of left neglect

• (Yoshihiro, 2017) applied FES to the limb while patient was driving a wheelchair vs driving a wheelchair without FES

  • Increased distance maneuvered in FES condition

  • Improved performance on cognitive test items related to extra-personal spaces

• Less conclusive evidence in this realm