"Transcortical" features of aphasia following left thalamic hemorrhage

In a series of 14 thalamic hemorrhage documented by Computerized Axial Tomography (CT) scans, aphasia was present in seven out of eight patients with left lesions while it was absent in the six patients with right lesions. In three cases where detailed language testing was performed, aphasia was characterized by reduction of spontaneous speech with semantic paraphasias, preserved repetition and partially defective auditory verbal comprehension. The language disturbance was persistent in two patients, while it recovered spontaneously within four weeks in one patient. The clinical picture in these patients is similar to the classical "transcortical" aphasias, which are usually due to damage of the marginal language areas. It is suggested that the left thalamus contributes to the semantic level of verbal behavior, which is possibly subserved by these areas.