Extrapyramidal dysfunction with cerebral arteriovenous malformations.

Arteriovenous malformations have only rarely been implicated as a cause of basal ganglia dysfunction. In four instances where such a lesion was uncovered, abnormal involuntary movements were present. In two, tremor involving the contralateral limbs occurred, while in others the head and neck were involved in dystonic movements and posture. The clinical and angiographic characteristics of these four patients have been assessed and are presented in detail in this report. The possible mechanism by which arteriovenous malformations may disturb the internal circuitry of the basal ganglia and induce symptoms are discussed.