Electrophysiological correlates of a paroxysmal movement disorder.

Averaged electroencephalographic activity related to rhythmic jerking movements was recorded in a patient with a complex neurological symptomatology. The diagnosis of a functional disorder was strongly suggested by his clinical course, inconsistent findings from physical examination, and negative workup. His abnormal movements were associated with the same electrophysiological correlates as normal willed motion, suggesting that averaged movement potentials may provide useful information in the study of patients with suspected functional movement disorders.