Improvements of Hand Function in Chronic Stroke Related to Upper Arm Anesthesia

This study will examine the effectiveness of an experimental treatment to improve hand function in patients who have had a stroke affecting one side of the body. One of the main problems of stroke patients is difficulty using the affected hand. Most treatments focus on acute (early) intervention, although special exercises may help some chronic patients. Previous studies have indicated that combining hand exercises with anesthesia (blocking motor and sensory function) of the upper arm may improve hand movement in stroke patients, even in the chronic state. This study will examine whether the exercise plus anesthesia treatment is more beneficial for these patients over the long-term than exercise alone.

Patients 18 years or older who are at least 12 months post stroke, which has affected only one side of the body, may be eligible for this study. Candidates will have a medical history and physical and neurological examinations.

Participants will be randomly divided into two groups: one will practice hand exercises without upper arm anesthesia and the other will exercise with anesthesia. All patients will perform two consecutive sessions of 30-minute pinch practice-forceful pinching of the thumb and index finger. Patients in the anesthesia group will have the anesthetic injected in the lower neck. Enough anesthetic will be administered to block motor and sensory function in the shoulder and upper arm, while maintaining as much function as possible in the forearm and hand.

All patients will also have transcranial magnetic stimulation (TMS) testing. For this procedure, a very brief electrical current is passed through an insulated wire coil placed on the head, producing a magnetic pulse. The pulse travels through the scalp and skull and causes small electrical currents in the outer part of the brain. During the study, the patient will be asked to make movements, do simple tasks, or tense muscles, while the electrical activity of the muscles is recorded.

Patients will have four sessions at 3-week intervals and three follow-up sessions at 3 weeks, 9 weeks and 24 weeks after the testing. Follow-up evaluations will include pinch power testing, TMS, sensory function test and hand function measurement.