Working Memory and Cognitive Skills in Individuals with Down Syndrome

Abstract

This work is aimed at analyzing working memory (WM) components and their relationships with other cognitive processes in individuals with Down syndrome (DS). Particular attention is given to examine whether a verbal WM deficit is due to difficulties in verbal abilities often showed by individuals with DS, or whether it is a deficit per se. A group of 20 individuals with DS was compared to a group of 20 typically developing (TD) children matched on vocabulary comprehension and to a group of 20 TD children matched on general verbal intelligence. The groups received a battery of 3 verbal and 3 visuospatial WM tasks requiring different degrees of control, and tests assessing verbal abilities (WPPSI verbal scale, PPVT), nonverbal skills (WPPSI performance scale), and logical thinking (LO). The results revealed that individuals with DS have deficits in both central executive (control) and verbal components of the WM system, and the latter one is independent of the general verbal abilities deficit. The data suggest that the development of central executive proceeds at a slower rate in individuals with DS and differently from TD children with comparable verbal abilities. The performance of individuals with DS on high-control WM tasks requires additional general resources that are strictly linked to intelligence.

Keywords:

• Down syndrome
• Intellectual disabilities
• Working memory
• Verbal memory
• Logical thinking

We thank all children who participated in this study, and their families. We also thank AGBD Association in Verona, AGENDO Association in Vicenza, and Don Calabria Institute in Verona. We thank Giulia Forcellini for her help with the data collection, Susie Hartley for editorial assistance, Gianluca Campana for his useful suggestions during the writing process, and Cesare Cornoldi, who provided helpful comments on a previous version of the manuscript.