Sex differences in the representation of visuospatial functions in the human brain.

Abstract

Sex differences in the representation of visuospatial functions in the human brain were investigated in 20 subjects with right hemisphere stroke and 40 stroke-free control subjects with the Complex Figure Test, WAIS-R Block Design, and Judgment of Line Orientation. The WAIS-R Similarities subtest was administered as a measure of verbal reasoning. The stroke and contro] groups were composed of equal proportions of males and females, and the male and femalestroke groups were matched for location and volume of infarction. A multivariate analysis of covariance determined that the interaction between stroke status and sex (p<.05), as well as the main effects for stroke status (p<.001) and sex (p<.001), were significantly related to visuospatial performance. None of these variables was significantly related to WAIS-R Similarities performance. The results of this study suggest that females may be disproportionately impaired in visuospatial functioning relative to males following right hemisphere stroke. We propose that visuospatial functions are bilaterally represented in the brains of males, allowing them to rely upon left hemisphere visuospatial systems following right hemisphere stroke, and that these functions are represented in the right hemisphere of females, resulting in their disproportionate impairment despite comparable lesions.The concept of sex differences in cognitive abilities has provoked much controversy. Numerous studies have been conducted focusing upon this issue, and many theories presented to account for the often conflicting findings (McGlone, 1980). Research with nonclinical populations has demonstrated small but consistent differences favoring males in visuospatial abilities and