Physiological Investigations of Movement Disorders

Background: * Previous studies have given researchers information on how the brain controls movement, how people learn to make fine, skilled movements, and why some people have movement disorders. However, further research is needed to learn more about the causes of most movement disorders, such as Parkinson's disease. * By using small, specialized studies to evaluate people with movement disorders and compare them with healthy volunteers, researchers hope to learn more about the changes in the brain and possible causes of movement disorders. Objectives: * To better understand how the brain controls movement. * To learn more about movement disorders. * To train movement disorder specialists. Eligibility: * Individuals 18 years of age or older who have had a movement disorder diagnosed by a neurologist and are able to participate based on the specific requirements of the small study. * Healthy volunteers 18 years of age or older. Design: * Participants will have a screening visit with medical history, physical examination, and questionnaire to determine eligibility. Eligible participants will give consent to participate in up to seven additional outpatient visits for study procedures. The number of sessions and the procedures needed for participation depend on specific symptoms. * Participants must avoid drinking alcohol or caffeinated drinks (sodas, coffee, and tea) for at least 2 days (48 hours) before each session. * Potential studies may include magnetic resonance imaging (MRI) scans, functional MRI scans, electroencephalography, magnetoencephalography, transcranial magnetic stimulation, nerve and sensory stimulation, or movement and mental tasks during any of the above procedures. * This study does not provide treatment for movement disorders. Participants will not have to stop any treatment in order to participate.

* INCLUSION CRITERIA: INCLUSION CRITERIA FOR MOVEMENT DISORDER PATIENTS: * Patients will either have a well-defined diagnosis or be a diagnostic dilemma, depending upon the sub-study * Age 18 or older * Able to give informed consent * Agree to not drink caffeine or alcohol for 48 hours before certain study sessions because both agents can modify brain activity and may confound outcome measures. INCLUSION CRITERIA FOR HEALTHY VOLUNTEERS: * Age 18 or older. * Able to give informed consent. * Agree to not drink caffeine or alcohol for 48 hours before certain study sessions because both agents may modify the activity of the brain during the study. EXCLUSION CRITERIA: EXCLUSION CRITERIA FOR MOVEMENT DISORDER PATIENTS: * Have used illegal drugs within the past 6 months * Have more than 7 alcoholic drinks a week in the case of a woman or 14 alcoholic drinks a week in the case of a man. * Have had a brain tumor, a stroke, head trauma, epilepsy or a history of seizures. * Have a psychotic disorder, Bipolar Disorder or a current depressive episode. * Have another neurologic disorder than a movement disorder * Have had a head injury where there was a loss of consciousness for more than a few seconds. EXCLUSION CRITERIA FOR HEALTHY VOLUNTEERS: * Have abnormal findings on a neurological examination that we will perform * Have used illegal drugs within the past 6 months * Have more than 7 alcoholic drinks a week in the case of a woman or 14 alcoholic drinks a week in the case of a man * Have had a brain tumor, a stroke, head trauma, epilepsy or a history of seizures. * Have major depression or any major mental disorders (axis I disorders) * Have had a head injury where there was a loss of consciousness for more than a few seconds. ADDITIONAL EXCLUSION CRITERIA FOR MOVEMENT DISORDER PATIENTS AND HEALTHY VOLUNTEERS SPECIFICALLY FOR fMRI: We will follow the NMR Center guidelines for MR safety. Some of the exclusions are: * Have non-MRI compatible metal in the body, such as a cardiac pacemaker, brain stimulator, shrapnel, surgical metal, clips in the brain or on blood vessels, cochlear implants, artificial heart valves or metal fragments in the eye as these make having an MRI unsafe. * Unable to lie flat on the back for the expected length of the experiment up to 3 hours * Have uncontrolled movements of the head * Have an abnormality on the brain imaging or neurologic examination not related to the diagnosis * Uncomfortable being in a small space for the expected length of the experiment up to 3 hours * Pregnancy ADDITIONAL EXCLUSION CRITERIA FOR MOVEMENT DISORDER PATIENTS AND HEALTHY VOLUNTEERS SPECIFICALLY FOR TMS: * Have metal in the eye or skull area, brain stimulator, shrapnel, surgical metal, clips in the brain, cochlear implants, metal fragments in the eye, as these make TMS unsafe. Having a cardiac pacemaker, intracardiac lines, implanted pumps or stimulators are also exclusion criteria. * Have hearing loss.