Cortical and subcortical aphasias compared

Abstract

Controversy surrounds differences between cortical and subcortical aphasias and their underlying pathophysiological mechanisms, but the necessary direct comparisons between clinical characteristics of patients with the two lesion types are lacking. We compared 36 stroke patients with subcortical lesions to 42 with cortical lesions of similar volume to determine the frequency, severity, and types of aphasia found in each group, and to examine subcortical clinicoanatomical correlations. Tested on the Western Aphasia Battery (WAB), the two groups did not significantly differ either in overall aphasia severity or on any WAB subtest scores. Although some individuals had relative preservation of repetition, we did not confirm an overall difference between patients with cortical and subcortical lesions in their ability to repeat. All subcortical patients were classifiable using the WAB and a broad spectrum of aphasia types was seen. Lesion volume did not significantly correlate with aphasia severity but anatomical features of subcortical lesions on computerized tomography (CT) could be related in many instances to the type of aphasia seen. However, variability in the deficits of patients with similar subcortical lesions still precludes the establishment of firm clinicoanatomical correlations or a unifying theory of subcortical involvement in language based on these data.