Transcranial Magnetic Stimulation in Parkinson's Disease

This study will use transcranial magnetic stimulation (TMS) to explore how the brain controls movement by sending messages to the spinal cord and muscles and what goes wrong with this process in disease. Activity in the motor cortex-the outer part of the brain-will be examined use TMS in patients with Parkinson's disease and in healthy volunteers. Normal volunteers and patients with Parkinson's disease (stage I to III) 21 years of age and older may be eligible for this study. All participants will have transcranial magnetic stimulation. For this procedure, an insulated wire coil is placed on the subject's scalp and a brief electrical current is passed through the coil. This creates a magnetic pulse that passes into the brain and generates very small electrical currents in the cortex, briefly disrupting the function of the brain cells in the stimulated area. This may cause muscle twitching or tingling in the face, jaw or limb. During the stimulation, participants will be asked to tense certain muscles slightly or perform other simple actions. The electrical activity of the muscle will be recorded on a computer through electrodes taped to the skin over the muscle. In most cases, the study will last less than 3 hours. Participants will also fill out questionnaires about aspects of personality and will be tested for their ability to perform certain cognitive (thinking) and movement tasks. Patients with Parkinson's disease will, in addition, be administered the Uniform Parkinson's Disease Rating Scale to measure disease severity. Patients will be requested to stop all Parkinson's disease medications 12 hours before the study. They may resume medications immediately after the study. Patients who so wish may be admitted to the hospital the day or evening before the study while they are off medications and stay there until they feel ready to leave.