Visuospatial working memory in specific language impairment: a meta-analysis

We conducted a meta-analysis of the data from studies comparing visuospatial working memory (WM) in children with specific language impairment (SLI) and typically developing (TD) children. The effect sizes of 21 studies (including 32 visuospatial storage tasks and 9 visuospatial central executive (CE) tasks) were identified via computerized database searches and the reference sections of the identified studies. Meta-analyses and moderator analyses were conducted to examine the magnitude of the differences in visuospatial storage and CE, and their relation to the inclusion criteria used for SLI and the age of the children. The results showed significant effect sizes for visuospatial storage (d=0.49) and visuospatial CE (d=0.63), indicating deficits in both components of visuospatial WM in children with SLI. The moderator analyses showed that greater impairment in visuospatial storage was associated with more pervasive language impairment, whereas age was not significant associated with visuospatial WM. The finding of deficits in visuospatial WM suggests domain-general impairments in children with SLI. It raises questions about the language-specificity of a diagnosis of SLI. Careful attention should thus be paid to both verbal and visuospatial WM in clinical practice, and especially in those children with pervasive language impairments.