[Transcortical sensory aphasia produced by lesions of the anterior basal ganglia area].

We reported three cases of an aphasic syndrome caused by unusual lesion distribution. Our patients, language disorders could be summarized as transcortical sensory aphasia and showed following symptoms; (1) fluent paraphasic verbal output, (2) anomia which was not facilitated by cueing, (3) impaired comprehension of spoken language, (4) preserved capacity of repetition, (5) preserved ability of reading aloud with impaired comprehension of the written material and (6) agraphia. In addition, all had no associated physical neurological signs such as hemiparesis or hemianopsia. All were right handed. All three cases showed the similar lesion distribution by computed tomographic scanning of the brain. All had low density areas in the anterior portion of the left basal ganglia including the head of the caudate nucleus, the anterior portion of the putamen, the anterior portion of the anterior limb of the internal capsule and the nearby white matter. Case 2 also had the small right hemisphere lesion in the white matter near the anterior portion of the lateral ventricle. Transcortical sensory aphasia with this lesion distribution has not been reported. We attributed the causative damage to lesions of the white matter and not to lesions of the basal ganglia per se. It was also speculated that fluent aphasia can be produced by the anteriorly situated white matter lesion if issuing fibers from the Broca's area were spared. Finally a possible anatomoclinical correlation for "transcortical alexia" (preserved oral reading and impaired reading comprehension) was attempted. The symptom is probably a reflection of the fact that the posterior speech area including the angular gyrus was left intact.