Physiology of Weakness in Movement Disorders

This study will compare electroencephalograph (EEG) recordings in healthy volunteers and in people with movement disorders to examine brain activity associated with the weakness. EEG records the electrical activity of the brain ("brain waves"). Healthy volunteers and patients with arm or leg weakness who are between 18 and 80 years of age may be eligible for this study. Healthy subjects are screened with a medical history, physical and neurological examinations, and a questionnaire. They must be right-handed and never have had a neurological disease or head trauma. All participants have an EEG. An elastic cap with electrodes is placed on the subject's scalp to record the brain's electrical activity. During the EEG, subjects are required to resist against a force with their arm, elbow, shoulder or leg for as long as they can. Several recordings are done with short breaks between them.