Cervical and facial myoclonus associated with dolichoectasia of the left vertebral artery.

A 52-year-old man presented with rapid jerking movements of his head to the right and clonic involuntary twitches involving his left eyelid and cheek. Electromyographic (EMG) recordings were consistent with left sternocleidomastoid and facial asynchronous myoclonus. Magnetic resonance imaging showed the presence of a dolichoectatic left vertebral artery displacing the medulla. Facial involvement and the asynchronism between cervical and facial myoclonus did not support a medullary origin for the movements. A direct compression of the eleventh and seventh cranial nerves by the dolichoectatic left vertebral artery may be the mechanism responsible for myoclonus in our patient.