Stroke Gait Rehabilitation Using Functional Electrical Stimulation

The study is a prospective interventional study to assess the changes in corticospinal excitability and spinal reflex excitability of in response to rehabilitative strategies and protocols that are commonly used during physical therapy treatment of gait disorders among post-stroke subjects. As part of this protocol, 55 individuals with chronic stroke will be assigned to either Cohort 1 or Cohort 2, and will participate in 1-18 gait training sessions. If interested, study participants can also complete both study cohorts sequentially (with at least 3-weeks duration between switching from one cohort to the second). The study examines the effects among two cohorts of post stroke patients. Cohort 1 will participate in 18 sessions of fast treadmill walking plus Functional Electrical Stimulation (FastFES) and Cohort 2 will participate in 1-3 sessions of FastFES and fast walking without FES.

Stroke is the number one cause of disability. Difficulty with walking affects most stroke survivors. Walking deficits (e.g. reduced ankle flexion during swing phase, decreased forward propulsion during terminal stance) can cause risks of falls, slow walking speed, increased effort of walking, and difficulties with activities of daily living. Restoration of walking ability can improve quality of life, and is perceived as a major goal of rehabilitation by stroke survivors. Examples of interventions that are used to rehabilitate walking post-stroke are functional electrical stimulation, fast treadmill walking, and bio- feedback. While recent research has focused on comparing the effectiveness of different gait rehabilitation interventions, the neural and biomechanical mechanisms underlying different gait rehabilitation strategies are unknown. FastFES is a novel gait training intervention that combines the beneficial effects of two independent interventions: Fast treadmill walking and FES. The FastFES intervention incorporates principles of physiology, biomechanics, motor control and learning, and predictions of forward-dynamic gait simulations to improve post-stroke gait.

The overall purpose of this protocol is to assess the biomechanical and neurophysiologic effects of rehabilitative strategies and protocols that are commonly used during physical therapy treatment of gait disorders post-stroke among two cohorts of people. Aim 1 of the study will assess the changes in gait biomechanics, corticospinal excitability, and walking function during 18 sessions of gait retraining, with participants in Cohort 1. Aim 2 of the study assesses the effect of parameters such as walking speed (slow, fast, variable, split-belt walking), functional electrical stimulation parameters (short-term changes induced by fast versus FastFES, stimulation intensity, number of muscles stimulated), and bio-feedback on within-session changes in gait biomechanics, walking function, and corticospinal excitability, among participants in Cohort 2.

Within Cohort 1, participants will receive identical treatment throughout the 18 training sessions (i.e. FastFES training). Within Cohort 2, participants will participate in 3 training sessions of both FastFES and fast walking training, with a 3-week break between the two types of training.

Eligibility Criteria:
Inclusion Criteria:

* Chronic stroke (\>6 months post stroke)
* First (single) lesion
* Able to walk with or without the use of a cane or walker
* Sufficient cardiovascular health and ankle stability to walk for 6 minutes at a self-selected speed without an orthoses
* Resting heart rate 40-100 beats per minute
* Resting blood pressure between 90/60-70/90

Exclusion Criteria:

* Evidence of moderate/ severe chronic white matter disease or cerebellar stroke on MRI
* Cerebellar signs (ataxic ("drunken") gait or decreased coordination during rapid alternating hand or foot movements
* Insulin dependent diabetes
* History of lower extremity joint replacement
* Score of \>1 on question 1b and \>0 on question 1c on NIH Stroke Scale
* Inability to communicate with investigators
* Neglect/hemianopia, or unexplained dizziness in last 6 months
* Neurologic conditions other than stroke
* Orthopedic problems in the lower limbs or spine (or other medical conditions) that limit walking
* Contraindications to transcranial magnetic stimulation (TMS) are: history of seizures, metal implants in the head or face, history of recurring or severe headaches/migraine, headache within the past 24 hours, presence of skull abnormalities or fractures, hemorrhagic stroke, history of dizziness, syncope, nausea, or loss of consciousness in the past 12 months