CT scan cerebral hemispheric asymmetry measurements in stroke cases with global aphasia: atypical asymmetries associated with improved recovery.

This study was undertaken in order to examine the relationship between CT scan hemispheric asymmetries and recovery in aphasia. The study had two parts. In Part I, hemispheric asymmetries were measured on the CT scans of 60 right-handed male non-aphasic (non-neurological) controls and 89 right-handed male aphasics, using a modification of LeMay's (1977) techniques. Both the non-aphasic control and aphasic data were in agreement with that of LeMay for frontal width, occipital width and occipital length. In Part II, the degree of CT scan hemispheric asymmetry was quantified for 14 right-handed male global aphasics, in whom differences in degree of language recovery were observed in the months following stroke. Atypical occipital asymmetries were significantly associated with certain aspects of language recovery (naming, single-word comprehension and single-word repetition). The authors postulate that increased capacity for right hemisphere contribution to language function might in part explain recovery in the cases exhibiting atypical occipital CT asymmetries.