The use of this technique has documented the existence of left-hemisphere lesions which lie outside the perisylvian cortex in patients who have aphasias. In addition to CT scans studies, recent reports of clinical -pathological correlations relating aphasia to a lesion in one of these sites- have also appeared. Four sites have been associated with these aphasias: the thalamus, the caudate, the white matter in the region of the internal capsule, and the supplementary motor area.