Moderators of Short-term and Working Memory Deficits in Children with Attention-deficit/Hyperactivity Disorder (Adhd): a Meta-analytic Review

Abstract

Extant literature has demonstrated conflicting results regarding whether or not working memory is a core deficit of Attention-Deficit/Hyperactivity Disorder. Studies that have not found consistent working memory deficits across children with ADHD may have included moderating (methodological and experimental) variables that suppressed between-group effects. Meta-analytic techniques were implemented to examine a broad range of moderating variables across working memory tasks between children with ADHD and their typically developing peers. Moderate overall effect sizes were found across working memory modalities (phonological and visuospatial). Results indicated that several moderating variables explained significant between-group differences on working memory tasks. Best case estimation procedures and percent overlap were calculated and revealed that combining best case moderating variables (based on empirical research) with visuospatial tasks is the most valid measure of working memory between groups. The current study offers explanation for why previous studies did not find working memory deficits in children with ADHD and lends further support for working memory as a core deficit of the disorder.