Transcortical motor aphasia Speech is non-fluent, but repetition and comprehension are spared. Lesions are frontal, but spare Broca's area. Comprehension is impaired, but repetition is normal. Lesions are posterior, but spare Wernicke's area. Anomic aphasia This can be conceived of as a mild transcortical sensory aphasia, in which comprehension is not affected, but naming is impaired.
Repetition is normal.
Angular and middle temporal gyrus lesions, as well as other areas, have been implicated. Mixed transcortical aphasia Non-fluent speech, with poor comprehension, but normal repetition. Lesions usually encompass thos of both transcortical motor and transcortical sensory aphasias, and are most often from watershed infarctions associated with severe carotid artery stenosis. Disconnection syndromes Neurological deficits may result not only from destruction of cortical regions that subserve specific functions, but also from disconnections between these areas. Most commonly caused by left posterior cerebral artery territory infarction, the lesion disconnects the right visual cortex from the left hemisphere language centers.