Verbal working memory in children with mild intellectual disabilities

Previous research into working memory of individuals with intellectual disabilities (ID) has established clear deficits. The current study examined working memory in children with mild ID (IQ 55-85) within the framework of the Baddeley model, fractionating working memory into a central executive and two slave systems, the phonological loop and visuo-spatial sketchpad.

Working memory was investigated in three groups: 50 children with mild ID (mean age 15 years 3 months), 25 chronological age-matched control children (mean age 15 years 3 months) and 25 mental age-matched control children (mean age 10 years 10 months). The groups were given multiple assessments of the phonological-loop and central-executive components.

The results showed that the children with mild ID had an intact automatic rehearsal, but performed poorly on phonological-loop capacity and central-executive tests when compared with children matched for chronological age, while there were only minimal differences relative to the performance of the children matched for mental age.

This overall pattern of results is consistent with a developmental delay account of mild ID. The finding of a phonological-loop capacity deficit has important implications for the remedial training of children with mild ID.