What type of electrical stimulation is recommended for stroke patients with an arm having partial muscle function?

Functional Electrical Stimulation for Stroke Patients with Partial Arm Muscle Function

For stroke patients with partial arm muscle function, functional electrical stimulation (FES) applied to the wrist and forearm muscles is recommended to reduce motor impairment and improve function. 1, 2

Type of Electrical Stimulation Recommended

FES is the specific modality indicated for patients with impaired muscle contraction, particularly targeting wrist motor impairment. 1 This involves electrical stimulation applied directly to muscles to cause contraction, serving as a time-limited intervention typically used during the first several weeks after stroke. 1

EMG-Triggered FES is Superior to Standard FES

• Neuromuscular electrical stimulation triggered or controlled by electromyography (EMG) is more effective than untriggered electrical stimulation for improving upper-limb motor impairment. 2, 3
• EMG-initiated electrical muscle stimulation—not electrical stimulation alone—improves motor function of the hemiparetic arm and hand. 3
• Power-assisted FES, which induces greater muscle contraction proportional to the voluntary EMG signal through closed-loop control, has shown good results in outpatient rehabilitation. 3

Clinical Application Protocol

Target Muscles and Positioning

• Apply FES to wrist and forearm extensors as the primary target for patients with partial function. 1, 2
• For comprehensive upper extremity rehabilitation, include interscapular muscles and shoulder muscles (supraspinatus and posterior deltoid) to improve reaching movements. 4, 5

Treatment Intensity and Duration

• Administer FES for 1 hour twice daily when intensive therapy is feasible, based on evidence showing functional gains with this regimen. 6
• Standard protocols involve 6 hours daily for 6 weeks with progressive increases in session duration and contraction/relaxation ratios as performance improves. 5
• Strong evidence supports efficacy for individuals less than 6 months post-stroke, though benefits can occur in chronic stroke patients. 2, 6

Integration with Conventional Therapy

• FES must be used as an adjunctive therapy to motor practice, not as standalone treatment. 2
• Combine FES with task-specific upper-limb movements using preprogrammed stimulation and manual assisted motion. 6
• FES combined with biofeedback produces better results than standard physical therapy, FES, or biofeedback alone. 2, 7

Expected Outcomes

Motor Function Improvements

• Patients regain the ability to initiate and stop muscle contraction voluntarily (approximately 5-15% of maximum voluntary contraction of the unaffected arm). 6
• Increased shoulder flexion and elbow extension during reaching movements, with less compensatory trunk flexion. 4, 8
• Improved muscle force in wrist extension, knee extension, and ankle dorsiflexion. 1

Additional Benefits

• Reduction in spasticity, as indicated by decreased H-reflex in wrist flexor muscles and improved Modified Ashworth Scale scores. 6
• Improvements in glenohumeral subluxation based on Cochrane review meta-analysis. 1
• Enhanced coordination between shoulder and elbow joints during functional tasks. 6

Critical Implementation Considerations

Patient Selection Criteria

• Partial muscle function qualifies patients for FES, unlike constraint-induced movement therapy which requires 20 degrees wrist extension and 10 degrees finger extension. 1
• FES is appropriate for patients with demonstrated impaired muscle contraction who fall below the threshold for intensive constraint-induced therapy. 2

Mechanism of Action

• FES promotes neural reorganization by providing sensory input and facilitating more complete muscle contractions, increasing proprioceptive feedback to the central nervous system that promotes motor learning. 2
• Cerebral blood flow in the sensory-motor cortex on the injured side is higher during power-assisted FES than during simple active movement or simple electrical stimulation. 3

Limitations to Acknowledge

• Evidence shows short-term increases in motor strength and control, but functional outcome improvements are less consistently demonstrated. 1
• Benefits may only be evident when the stimulator is actively used, with variable effects on maintenance of functional gains. 2, 7
• Studies have inconsistent stimulation protocols regarding pulse duration and frequency, making standardization difficult. 2

Common Pitfalls to Avoid

• Do not use FES alone without concurrent motor practice and task-specific training, as the combination is essential for optimal outcomes. 2
• Avoid applying FES without EMG triggering when available, as triggered stimulation is more effective than untriggered protocols. 2, 3
• Do not delay initiation—early application within the first 6 months post-stroke shows stronger evidence of efficacy. 2