Working memory in aphasia: Peeling the onion

Compared to neurologically healthy adults, persons with aphasia (PWA) demonstrate impaired performance on working memory (WM) tasks. These deficits in WM are thought to underlie language processing problems in PWA. However, most studies use WM tasks that are verbal in nature, making it difficult to determine if these deficits are due to domain-general attentional processes related to WM or domain-specific verbal abilities. The purpose of the current study was to examine WM performance in PWA and healthy controls using verbal and spatial WM tasks. Additionally, this study investigated the relationship among WM performance and performance on short-term memory and domain-general attentional tasks. Fourteen PWA and 13 control participants completed verbal and spatial n-back tasks, the Flanker arrows task, and forward digit and spatial span tasks. The results revealed that the PWA performed worse than the control participants on the verbal tasks, but there were no group differences on the spatial tasks. Further, PWA showed significantly greater conflict and interference effects on the Flanker arrows task than control participants. These findings suggest that although WM deficits are primarily evident in the verbal domain in PWA, they are not solely the result of domain-specific verbal deficits; the ability to inhibit irrelevant information may contribute to WM deficits in PWA.