Working memory functioning in children with attention-deficit/hyperactivity disorder (ADHD): A comparison between subtypes and normal controls

摘要

Objective: Children with attention-deficit/hyperactivity disorder (ADHD) often experience working memory difficulties. However, research findings are inconsistent, making it difficult to compare results across studies. There are several reasons for this inconsistency. Firstly, most studies make no distinction between ADHD subtypes, despite evidence that predominantly inattentive ADHD (ADHD/I) represents a different neurocognitive profile to the hyperactive-impulsive subtype (ADHD/HI). Secondly, documented studies use different tests of working memory which may be measuring different skills. Some assess only the verbal components of working memory and others the visuo-spatial; few of the tests assess both. Further, some tests employ a recognition methodology and others use recall, which require different brain regions and cognitive processes. To clarify these inconsistencies, the verbal and visuo-spatial working memory of children with ADHD/I, ADHD/HI and a control group with no ADHD symptoms were compared.