Position-dependent hemifacial spasm.

Hemifacial spasm developed in a 32-year-old man following a brain stem stroke. This stroke followed a self-induced head movement, which is a rare cause of such events. The clonic movements were often related entirely to the position of the head. Carbamazepine was successful in treating the spasm and may be indicated in the medical treatment of this disorder. The differential diagnosis and treatment of hemifacial spasm are discussed.