Speech discrimination and phonological working memory were examined in children with ADHD (N=9), ADHD plus developmental coordination disorder (ADHD+DCD) (N=13), and 19 age-matched controls, in a study at the Neuropediatric Unit, Karolinska Institute, Stockholm, Sweden. Tests requiring monosyllabic discrimination showed no significant differences between subject groups, whereas the ADHD+DCD group scored significantly lower in tests involving exposure to multisyllabic (2-5) non-word pairs and speech discrimination with a working-memory load. The low performance in the ADHD children with complicating DCD was the result of impaired memory rather than of speech-discrimination problems. [1]

COMMENT. Language problems are reported in 65% of children with ADHD and motor-perception impairments (DCD), and hyperactive behavioral disorders affect approximately the same proportion of children with learning disabilities. Phonological awareness and working memory are important in the acquisition of reading and writing skills. The present study suggests that deficits in working memory may contribute to the high incidence of dyslexia among children with ADHD, and may explain their motor-perception impairments by effects on storage of motor commands at an early age. See Denckla MB [2], for an account of the phonological-linguistic basis of dyslexia, its anatomic-phsiologic correlates, and the overlap between reading disability and other learning disabilities with “ADD(H).”