Subcortical contributions to drawing

Abstract

Constructional impairment is often considered a sign of cortical damage. However, aphasia, agraphia, and apraxia, disorders traditionally deemed cortical, have been well described following subcortical lesions, suggesting an important role for subcortical structures in cognition. Drawing impairment following subcortical lesions has not been systematically explored or compared with that following cortical damage. We examined relative incidence and severity of drawing impairment after cortical and subcortical strokes and whether there were qualitative differences between these two groups' drawings. Drawings by 125 patients with single hemispheric strokes of similar volume (42 left cortical, 36 left subcortical, 20 right cortical, 27 right subcortical) were compared using a standardized scoring system. Although previously noted right/left differences were confirmed, "subcortical drawings" did not differ from "cortical drawings" on any measures, including overall impairment. Compared with cortical patients, drawing impairment in those with subcortical lesions (especially left) was more strongly associated with impairment of other cognitive abilities. Thus, although a subcortical lesion does not cause more severe drawing impairment, subcortical lesions affecting drawing lead to more widespread cognitive dysfunction than do similarly sized cortical lesions. Drawing impairment often follows subcortical strokes and is by no means an indicator of cortical lesion localization.