Locomotor Function Following Transcutaneous Electrical Spinal Cord Stimulation in Individuals With Hemiplegic Stroke

This study has two interventional components, the first is a cross-over design and the second is a randomized control trial. Both will evaluate the effectiveness of transcutaneous (non-invasive) spinal cord stimulation on gait and balance function for individuals with hemiplegia due to stroke.

OBJECTIVES:

* Exploratory phase: Identify a systematic, methodical approach to identifying the optimal stimulation parameters and gait training protocol for each individual patient with stroke.
* Aim 1: Evaluate short-term effects of transcutaneous spinal cord stimulation + gait training on gait symmetry, gait performance, and corticospinal circuitry in individuals with chronic stroke.
* Aim 2: Evaluate and predict long-term effects of transcutaneous spinal cord stimulation + gait training on gait symmetry, gait performance, and corticospinal circuitry in individuals with chronic stroke
* Aim 3: Identify parameters that distinguish responders from non-responders to transcutaneous spinal cord stimulation in individuals with chronic stroke.

Eligibility Criteria:
Inclusion Criteria

* Age 18 years or older
* Able and willing to give written consent and comply with study procedures
* At least 6 months' post-stroke
* Hemiplegia secondary to a single stroke
* Functional Ambulation Category of 2 or greater - i.e., subject needs continuous or intermittent support of one person to help with balance and coordination.
* Not currently receiving regular physical therapy services
* Physician approval to participate

Exclusion Criteria

* Ataxia
* Multiple stroke history
* Botox injection in lower extremity within the last 4 months
* Modified Ashworth score of 3 or greater in lower extremity
* Pregnant or nursing
* Using a powered, implanted cardiac device for monitoring or support of heart function (i.e. pacemaker, defibrillator, or LVAD) or anti-spasticity implantable pumps
* Active pressure sores
* Unhealed bone fractures
* Peripheral neuropathies
* Painful musculoskeletal dysfunction due to active injuries or infections
* Severe contractures in the lower extremities
* Medical illness limiting the ability to walk
* Active urinary tract infection
* Clinically significant depression, psychiatric disorders, or ongoing drug abuse
* Active cancer or cancer in remission less than 5 years
* Orthopedic dysfunction, injury, or surgery that would impact an individual's ability to use the lower extremity.
* Traumatic brain injury or other neurological conditions that would impact the study.

TMS-Specific Exclusion Criteria: TMS will be utilized for both Aims. The sub-set of participants who meet these criteria will participate in this component of the studies.

* Medicated with agents known to increase (e.g., amphetamines) or decrease motor system excitability (e.g., lorazepam)
* Implanted cardiac pacemaker
* Metal implants in the head or face
* Suffers unexplained, recurring headaches
* Had a seizure in the past unrelated to the stroke event, or has epilepsy
* Skull abnormalities or fractures
* A concussion within the last 6 months
* Unstable cardiorespiratory or metabolic diseases (e.g. cardiac arrhythmia, uncontrolled hypertension, uncontrolled diabetes, or chronic emphysema)