Orthostatic-mediated hypoperfusion in limb-shaking transient ischemic attack

In patients with severe carotid stenosis or total occlusion, episodic contr alateral motor dysfunction is more likely related to cerebral hypoperfusion than epileptogenic activity. A man with orthostatic-mediated right-sided l imb shaking was found to have total left internal carotid artery occlusion. There was prominent reduction of cerebrovascular reserve seen on single ph oton emission computed tomography (SPECT) performed with and without acetaz olomide. During assumption of an upright position transcranial Doppler (TCD ) revealed a marked attenuation of the left middle cerebral artery flow pat tern not associated with changes during electroencephalographic monitoring, even after administration of acetazolomide. In this man, limb shaking epis odes were attributed to hypoperfusion of the contralateral cerebral hemisph ere, and not to epileptogenic activity.