Working memory and motor activity in children with ADHD: Does stimulus presentation modality matter?

Abstract

Empirical support for the functional relationship between working memory (WM) and motor activity is well established for children with attention-deficit/hyperactivity disorder (ADHD) and typically developing (TD) children. The episodic buffer component of WM, however, has been subject to few empirical investigations in children, and only once examined with respect to the functional relationship between WM demands and motor activity. Motor activity of forty-two children (ADHD = 23, TD = 19) aged 8 to 12 years was recorded while they were administered three versions of a phonological WM task that varied with regard to stimulus presentation modality (auditory, visual, or dual auditory and visual), as well as a visuospatial task and a control task. Mixed model analyses of variance indicated that children’s WM performance varied according to stimulus presentation modality and that activity remained relatively stable across tasks. Further examination indicated that motor activity changes were influenced primarily by changes in central executive demands across tasks. Overall, findings suggest that episodic buffer processes (elicited via dual modality presentation of verbal stimuli- information that is processed via a visual and verbal code) benefits WM performance but does not appear to impact motor activity above and beyond the contribution of central executive demands.