Isolation of speech area from focal brain ischemia.

A patient with atrial fibrillation and internal carotid artery occlusion developed mixed transcortical aphasia. The CT scan showed two recent distinct infarcts in the dominant hemisphere, one in the precentral artery area (pial artery infarct) and one in the borderzone area between the posterior and middle cerebral arteries territories (watershed infarct). The perisylvian speech areas were spared, but probably disconnected from other areas by the infarcts. The syndrome of isolation of speech area may be caused by vascular conditions which are able to produce simultaneous pial artery and watershed infarcts, and is not necessarily related to more extensive processes of the brain.