AIH-induced Walking Recovery After Subacute SCI

Inclusion Criteria: * 18 to 70 years old * medically stable with medical clearance from physician to participate * spinal cord injury (SCI) at or below C3 (phrenic sparing) and above L5 with at least motor function preserved below the neurologic level * non-progressive etiology of spinal injury * American Spinal Injury Association Impairment Scale (AIS) grade A-D * 2-12 months post-injury (subacute) Exclusion Criteria: * severe concurrent illness or pain, including unhealed decubiti, severe neuropathic or chronic pain syndrome, infection (e.g. bladder), hypertension, cardiovascular disease, pulmonary disease, severe osteoporosis (history of fractures), active heterotopic ossification in the lower extremities, or history of peripheral nerve injury in the legs * score less than 24 on Mini-Mental Exam * severe autonomic dysreflexia * history of cardiovascular/pulmonary complications * pregnancy * severe obstructive sleep apnea (OSA), characterized by uncontrolled hypoxia and sleep fractionation Specific inclusion/exclusion criteria for recruiting non-ambulatory subjects: Participation in this group requires all of the above inclusion/exclusion criteria, as well as being unable to complete any of the below measures: * timed up-and-go (TUG) test * 10-meter walk test (10MWT) * 6-minute walk test (6MWT) Specific inclusion/exclusion criteria for recruiting ambulatory subjects: Participation in this group requires all of the above criteria, as well as successful completion of …