Neurophysiological Markers in Patients With Craniofacial Dystonia and Their Relatives

This study will use a technique called blink reflex to study and compare how the brain controls muscle movement in patients with craniofacial dystonia, their first-degree relatives, and healthy, normal volunteers. People with dystonia have sustained muscle contractions that cause twisting and repetitive movements or abnormal postures. In focal dystonia, this happens in one area of the body, such as the hand, neck, or face.

Three groups of people may be eligible for this study: 1) patients 18 years of age and older with craniofacial dystonia; 2) first-degree relatives of patients with craniofacial dystonia; and 3) normal volunteers matched in age to the patients. Candidates are screened with physical and neurological examinations.

Participants undergo a blink reflex study. Patients with dystonia who are receiving botulinum toxin injections must stop the medication 3 months before participating in the study and must stop any other dystonia medications, such as benzodiazepines and anticholinergics, for 12 hours before the study. For the blink reflex procedure, subjects are seated in a comfortable chair with their hands placed on a pillow on their lap. Metal electrodes are taped to the forehead for delivering small electrical shocks that feel like very brief pinpricks. Subjects receive 25 to 50 electrical stimuli, some as single shocks and some in pairs. The electrical activity of muscles that respond to the stimuli is recorded with a computer. The study takes from about 1 to 2 hours.