Working Memory in Children with Learning Disabilities: Rethinking the criterion of discrepancy

Abstract

The criterion of discrepancy is used to distinguish children with learning disorders from children with intellectual disabilities. The justification of the criterion of discrepancy for the diagnosis of learning disorders relies on the conviction of fundamental differences between children with learning difficulties with versus without discrepancy to intelligence. But the open question is whether these two groups are really characterised by different cognitive functioning. This question was examined in three studies in which several functions of working memory according to Baddeley were explored. A working memory battery with tasks for the phonological loop, the visual–spatial sketchpad and central executive skills was presented in individual sessions to children with learning disabilities (dyslexia or dyscalculia or mixed disorders of scholastic skills) and normal IQ, to children with the same problems but lower IQ, and to control groups of children with regular school achievement and normal IQ. Results reveal specific deficits in working memory in the groups with learning disabilities compared with the control groups. However, there were no differences between the disabled groups with normal versus lower intelligence. These findings do not support the notion of discrepant cognitive functioning due to differences in intelligence of the groups, and therefore lead to doubts about the validity of the criterion of discrepancy.