PI is leaving the university.

Subjects will receive non-invasive stimulation of nerves on their arm and intensive motor training of their arm. The timing of the stimulation in relation to the training will vary by group.

This study will look at the differences in improvement of hand and arm function when nerve stimulation is applied at different times in relation to motor training. The nerve stimulation, called peripheral nerve stimulation (PNS), is non-invasive and painless. Subjects in the study may receive strong or mild PNS. Subjects will also vary by whether PNS is delivered for 2 hours before the 2 hours of motor training, or during the 2 hours of motor training. Which level of stimulation and its timing will be determined randomly for each subject.

Inclusion Criteria:

• Have severe upper extremity motor deficit after a single stroke
• Stroke onset at least 12 months ago

Exclusion Criteria:

• Addition or change in the dosage of drugs known to exert detrimental effects on motor recovery within 3 months of enrollment
• Untreated depression
• History of multiple strokes
• History of seizure
• History of head injury with loss of consciousness, severe alcohol or drug abuse, or psychiatric illness
• Positive pregnancy test or being of childbearing age and not using appropriate contraception
• Presence of ferromagnetic material in the cranium except in the mouth, including metal fragments from occupational exposure, and surgical clips in or near the brain
• Cardiac or neural pacemakers or implanted medication pumps
• Receptive aphasia