Protocol Number: 07-N-0122
Healthy normal volunteers 18 years of age or older may be eligible for this study. Candidates are screened with a medical and neurological history and examination. The study involves one to twenty 4-hour experimental sessions completed over 1 to 12 months. During each session, participants receive some combination of mild electrical peripheral nerve stimulation, magnetic transcranial stimulation (TMS), and electrical transcranial stimulation (TMS and tDCS, respectively). No more than two forms of stimulation are combined during any one session, with no more than 3 hours of stimulation during the session. Each session includes some of the following tests: -Surface electromyography: Electrodes filled with a conductive gel are taped to the skin to measure and record the electrical activity of the nerves and muscles of the arm or leg. -TMS measurements: A wire coil is held on the scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. During the stimulation, the subject may be asked to tense certain muscles slightly or perform other simple actions. The stimulation may cause a twitch in muscles of the arm or leg, and the subject may hear a click and feel a pulling sensation on the skin under the coil. -tDCS: Small, wet sponge electrodes are applied to various places on the head. A small electrical current is passed between them. The subject may feel an itching or tingling sensation under the electrodes or see light flashes. -Peripheral nerve stimulation: Two pairs of electrodes are placed on the arm or leg to stimulate and record from the nerves and muscles beneath them. -Magnetic resonance imaging (MRI): The subject lies on a bed that slides into a tubular scanner surrounded by a strong magnetic field. Earplugs are worn to muffle loud noises that occur during the scanning. The procedure lasts about 60 minutes, with the subject asked to lie still for up to 20 minutes at a time. -Motor function tests: Subjects perform motor function tests at the beginning and end of each session. The tests might include pinching a force-measuring instrument with their fingers, pressing keys on a keyboard as fast as possible, inserting pegs into a pegboard, lifting weights, flipping cards, and others. -Questionnaires: Subjects complete questionnaires at the end of each session to rate their fatigue, loss of attention and pain or other discomfort.
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National Institutes of Health Clinical Center
Bethesda, Maryland 20892. Last update: 01/13/2009
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