Mechanisms of Walking Recovery After Stroke

Inclusion Criteria:

• age 30-90 years
• unilateral stroke experienced >6 months prior to enrollment in middle cerebral artery (MCA) territory without complete disruption of the putamen on the lesion side
• walking speed <= 1.0 m/s on the 10 meter walk test
• able to walk 10m over ground with assistive devices as needed and no physical assistance

Exclusion Criteria:

• MRI incompatibility (e.g. metallic or electronic implants, severe claustrophobia)
• inability to perform mental imagery (time dependent motor imagery screening test [TDMI])
• evidence of significant arrhythmia or myocardial ischemia on treadmill ECG stress test, or significant baseline ECG abnormalities that would make an exercise ECG uninterpretable
• recent (<3 months) cardiopulmonary hospitalization
• unable to communicate with investigators or correctly answer consent comprehension questions
• significant ataxia or neglect (score of 2 on NIH stroke scale item 7 or 11)
• severe lower extremity (LE) spasticity (Ashworth >2)
• recent (<3 months) illicit drug or alcohol abuse or significant mental illness
• major post-stroke depression (PHQ-9 ≥10) in the absence of medical management
• participating in physical therapy or another interventional research study;
• recent (<3 months) paretic LE botulinum toxin injection
• concurrent progressive neurologic disorder or other major medical, orthopedic or peripheral vascular conditions that would limit improvement
• pregnancy