A reexamination of the visuospatial deficit in Turner syndrome: Contributions of working memory

Studies describing deficits in children with Turner Syndrome (TS) typically report that visual and spatial processing are impaired relative to verbal processing (Rovet & Netley, 1982). The exact nature of this deficit is not entirely clear, however, because the tasks that have been used to date (e.g., mental rotation, part-whole and left-right decisions, etc.) do not distinguish between what Kosslyn (1980) described as the two components of visual processing: locating an object in space (where?) and determining the identity of an object (what?). We report findings from an experiment designed to examine visual processing and working memory in children with TS and normal control children. However, unlike previous examinations of visuospatial processing in TS, the reported experiments tease apart what and where aspects of the visual system. Moreover, they examine separately the contributions of both visual and verbal working memory to visuospatial processing. Differences between children with TS and normal controls indicate that the core deficit is in visuospatial working memory. Correlations with karyotype information from the girls with TS provide some preliminary support for a gene-dosage hypothesis.