How does the severity of a learning disability affect working memory performance?

Working memory performance was examined in children aged 11-12 years who ha d borderline, mild, and moderate learning disabilities. Comparisons with ch ildren of average abilities were used to determine whether those with more severe learning disabilities had greater impairments in working memory. Sev en measures of working memory span were used to assess temporary phonologic al short-term storage (digit span, word span), temporary visuo-spatial shor t-term storage (pattern span, spatial span), and temporary short-term stora ge with additional processing, or central executive, demands (listening spa n, odd one out span, reverse digit span). Children with mild and moderate l earning disabilities were impaired on all measures of working memory compar ed to children of average abilities. Children with borderline learning disa bilities were just as good as children with average abilities on visuo-spat ial and complex span tasks, but showed an impairment on phonological span t asks. Children with moderate learning disabilities were indistinguishable f rom children with mild learning disabilities on simple span tasks, but were significantly poorer than the mild group on the more demanding complex spa n tasks. For the group as a whole, working memory was strongly related to m ental age.