Working memory function in attention deficit hyperactivity disordered and reading disabled children

The aim of the current study was to examine the nature of executive processing in working memory as a core deficit in attention deficit hyperactivity disorder (ADHD) as distinct from deficits associated with reading disability (RD). This involved examination of the working memory processes of the phonological loop and central executive (Baddeley, 1986) as a potential means of differentiating ADHD from RD. The participants were 16 ADHD/RD, 16 RD and 16 normal control children, matched for sex, age and IQ, who performed tasks tapping phonological loop function, a combination of phonological loop and central executive functioning, and tasks relying on central executive functioning. Analysis revealed that as the involvement of the central executive in tasks increased, ADHD/RD children performed worse than the other groups. This was on measures of controlled information processing, modifying and accommodating new input and supervisory capacity. These findings reflect the potential utility of the central executive in working memory in understanding the nature of executive processing deficits in ADHD. They also support the efficacy of these tasks in discriminating ADHD from RD.