Alternating paroxysmal hemiballism-hemichorea in bilateral internal carotid artery stenosis

A 72-year-old man presented with paroxysmal and transient involuntary movem ents, or "limb shaking". The attacks occurred alternately from one side of the body to the other and ceased spontaneously. Surface EMG study showed sy nchronous grouping discharges in multiple limb muscles, being compatible wi th hemiballism-hemichorea. Cerebral angiography demonstrated marked stenosi s of the bilateral internal carotid arteries. Bilateral carotid endarterect omy led to complete disappearance of the involuntary movements. Alternating paroxysmal hemiballism-hemichorea might be a transient ischemic attack, an d alternating striatal dysfunction induced by cerebral hemodynamic or micro embolic ischemia probably plays a central role in the occurrence of such in voluntary movements.