Role of Electrical Stimulation in Post-Stroke and Nerve Injury Rehabilitation
Functional electrical stimulation (FES) and neuromuscular electrical stimulation (NMES) are recommended as effective adjunctive therapies for both upper and lower extremity motor outcomes in post-stroke and nerve injury rehabilitation. 1
Mechanisms and Benefits
- Electrical stimulation 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 1
- Strong evidence supports the efficacy of electrical stimulation for individuals less than 6 months post-stroke, with studies showing improved outcomes when regular therapy is combined with FES compared to regular therapy alone 1
- FES systems can be classified as open-loop (manually controlled) or closed-loop (brain-computer interface or electromyography controlled), with all types showing favorable outcomes for stroke recovery of functional movements 2
Upper Extremity Applications
- Electrical stimulation for the upper extremity has shown effectiveness in improving motor control and various motor outcomes at the shoulder, particularly in acute stroke 1
- For shoulder subluxation, electrical stimulation has demonstrated improvements, though evidence regarding its effect on shoulder pain or function is conflicting 1
- Recent systematic reviews have found that neuromuscular electrical stimulation triggered or controlled by electromyography is effective in improving upper-limb motor impairment 1
- Meta-analyses show benefits of NMES for improvement in activities of daily living (ADL) function, though evidence for improvement in functional motor ability is less clear 1
Lower Extremity Applications
- For the lower extremity, FES has been recommended for patients with ankle/knee/wrist motor impairment and for gait training after stroke 1
- FES combined with biofeedback has shown better results than standard physical therapy, FES, or biofeedback alone in improving gait parameters 1
- FES combined with physical therapy is superior to physical therapy alone in improving gait speed while reducing energy cost, though benefits may only be evident when the stimulator is used 1
- Implantable nerve stimulators have been found to be safe and effective in reducing foot drop during ambulation in stroke survivors, with improvements in gait speed and walking endurance 1
- Bilateral transcutaneous electrical nerve stimulation (TENS) combined with task-oriented training has shown superior results in improving paretic ankle dorsiflexion strength and Timed Up and Go test performance compared to unilateral TENS 3
Most Effective Current Types and Parameters
- While studies have variable stimulation protocols in pulse, duration, and frequency, the most recent evidence supports the following approaches 1:
- For upper extremity: EMG-controlled FES systems have shown the greatest improvements in Fugl-Meyer Assessment scores (mean difference = 14.14) compared to manually controlled FES (mean difference = 5.6) and BCI-controlled FES (mean difference = 5.37) 2
- For lower extremity: Continuous theta burst electrical stimulation has shown promising results in reducing neural damage when applied early after stroke 4
- For foot drop: TENS applied over the common peroneal nerve combined with task-oriented training improves ankle dorsiflexion strength and functional mobility 3
Clinical Implementation
- Electrical stimulation should be used as an adjunctive therapy to motor practice rather than as a standalone treatment 1
- Patient selection is important - FES for shoulder subluxation is recommended for appropriate candidates 1
- The timing of intervention matters - early application (within the first 6 months post-stroke) shows stronger evidence of efficacy 1
- For foot drop specifically, a multidisciplinary approach involving orthotists, physical therapists, and podiatrists is recommended for appropriate device fitting, rehabilitation, and foot care 5
Limitations and Considerations
- The effects of electrical stimulation on the maintenance of functional gains are variable 1
- Studies have inconsistent stimulation protocols in terms of pulse, duration, and frequency, making standardization difficult 1
- Patient-specific factors such as the degree of paralysis should guide the selection of appropriate NMES devices and stimulation methods 6
- For patients with spasticity, botulinum toxin may be more effective than electrical stimulation for certain applications, particularly for ankle spasticity 1
By incorporating electrical stimulation into rehabilitation programs for post-stroke and nerve injury patients, clinicians can enhance motor recovery and functional outcomes when used appropriately as part of a comprehensive treatment approach.