Functional Electrical Stimulation for Footdrop in Hemiparesis

The objective of this research is to determine if electrical stimulation can improve the strength and coordination of the lower limb muscles, and the walking ability of stroke survivors.

The knowledge gained from this study may lead to enhancements in the quality of life of stroke survivors by improving their neurological recovery and mobility. The results may lead to substantial changes in the standard of care for the treatment of lower limb hemiparesis after stroke.

Hemiplegia is a major consequence of stroke and contributes significantly to the physical disability of stroke survivors. Foot-drop, or inability to dorsiflex the paretic ankle during the swing phase of gait, and ankle instability during stance phase, are important gait abnormalities that contribute to reduced mobility among stroke survivors. In the United States, the standard of care in addressing these deficits is the custom molded ankle-foot-orthosis (AFO). However, evolving data now demonstrate that active repetitive movement training is the principal substrate for facilitating motor relearning after stroke. Motor relearning is defined as the reacquisition of motor ability after central nervous system injury. Thus, while an AFO may assist stroke survivors to ambulate in the short-term, it is possible that it also inhibits recovery in the long-term. Previous studies have demonstrated that active repetitive movement exercises mediated by neuromuscular electrical stimulation (NMES) facilitate motor relearning among stroke survivors. In particular, studies have reported that some chronic stroke survivors treated with a peroneal nerve stimulator for foot-drop experience sufficient recovery that they no longer need the peroneal nerve stimulator or an AFO for community ambulation. However, there are no blinded randomized clinical trials that rigorously evaluate the motor relearning effects of ambulation training with peroneal nerve stimulators. Thus, the primary aim of this project is to assess the effects of transcutaneous peroneal nerve stimulation on lower limb motor relearning among chronic stroke survivors. The secondary aim is to assess the effects of transcutaneous peroneal nerve stimulation on lower limb mobility (disability) and overall quality of life. A single-blinded randomized clinical trial will be carried out to assess the effects of ambulation training with a peroneal nerve stimulator among chronic stroke survivors compared to ambulation training with conventional standard of care (which may include an AFO). Subjects will be treated for 12 weeks and followed for a total of another 6 months. This project will determine the effectiveness of peroneal nerve stimulation in facilitating motor relearning and improving the mobility and quality of life of stroke survivors. This proposed approach is expected to improve patient outcome and challenge the present clinical paradigm of prescribing AFOs for stroke survivors with foot-drop.

Eligibility Criteria:
Inclusion Criteria:

* Stroke survivors \>90 days from most recent clinical hemorrhagic or nonhemorrhagic stroke
* Age: 18-80 years
* Unilateral hemiparesis
* Medically stable
* Sufficient endurance \& motor ability to ambulate at least 30 feet continuously with minimal assistance \[requiring contact guard to no more than 25% physical help\] or less without the use of an AFO
* Berg Balance Scale score of 24 or greater without any assistive devices
* Ankle dorsiflexion strength of no greater than 4/5 on the Medical Research Council (MRC) scale while standing
* Demonstrate foot-drop during ambulation such that gait instability \[need for supervision, physical assistance or assistive device (cane, walker) to maintain balance or prevent falls\] or inefficient gait patterns \[gait pattern manifesting "dragging" or "catching" of the affected toes during swing phase of gait, or use of compensatory strategies such as circumducting the affected limb, vaulting with the unaffected limb or hiking the affected hip to clear the toes\] are exhibited
* Ankle dorsiflexion to at least neutral while standing in response to NMES of the common peroneal nerve without painful hypersensitivity to the NMES
* If using an AFO, willing to terminate its use and comply with study requirements

Exclusion Criteria:

* Require an AFO to maintain knee stability (prevention of knee flexion collapse) during stance phase of gait
* Edema of the affected lower limb which interferes with the safe and effective use of a peroneal nerve stimulator
* Skin breakdown of the affected lower limb which interferes with the safe and effective use of a peroneal nerve stimulator
* Absent sensation of the affected lower limb
* History of potentially fatal cardiac arrhythmias, such as ventricular tachycardia, supraventricular tachycardia, and rapid ventricular response atrial fibrillation with hemodynamic instability
* Demand pacemakers or any other implanted electronic systems
* Pregnant women
* Uncontrolled seizure disorder
* Parkinson's Disease
* Spinal cord injury
* Traumatic brain injury with evidence of motor weakness
* Multiple sclerosis
* Fixed ankle plantar flexor contracture
* Peroneal nerve injury at the fibular head as the cause of foot-drop
* Uncompensated hemineglect
* Severely impaired cognition and communication
* Painful hypersensitivity to NMES of the common peroneal nerve
* Inadequate social support (potential unlikeliness to comply with treatment \& follow-up)
* History of Botulinum toxin (Botox) injection to either of the lower extremities within the 3 month period preceding study entry
* Knee hyperextension (genu recurvatum) that cannot be adequately corrected with peroneal nerve stimulation