Movement-Related Brain Networks Involved in Hand Dystonia

This study will use various methods to measure the activity of the motor cortex (the part of the brain that controls movements) in order to learn more about focal hand dystonia. Patients with dystonia have muscle spasms that cause uncontrolled twisting and repetitive movement or abnormal postures. In focal dystonia, just one part of the body, such as the hand, neck or face, is involved. Patients with focal hand dystonia and healthy normal volunteers between 18 and 65 years of age may be eligible for this study. Each candidate is screened with a medical history, physical examination and questionnaire. Participants undergo the following procedures: Finger Movement Tasks Subjects perform two finger movement tasks. In the first part of the study, they move their index finger repetitively from side to side at 10-second intervals for a total of 200 movements in four blocks of 50 at a time. In the second part of the study, subjects touch their thumb to the other four fingers in sequence from 1, 2, 3 and 4, while a metronome beats 2 times per second to help time the movements. This sequence is repeated for a total of 200 movements in four blocks of 50 at a time. Electroencephalography This test records brain waves. Electrodes (metal discs) are placed on the scalp with an electrode cap, a paste or a glue-like substance. The spaces between the electrodes and the scalp are filled with a gel that conducts electrical activity. Brain waves are recorded while the subject performs a finger movement task, as described above. Magnetoencephalography MEG records magnetic field changes produced by brain activity. During the test, the subjects are seated in the MEG recording room and a cone containing magnetic field detectors is lowered onto their head. The recording may be made while the subject performs a finger task. Electromyography Electromyography (EMG) measures the electrical activity of muscles. This study uses surface EMG, in which small metal disks filled with a conduc