Neuropsychological Aspects of Developmental Dyscalculia

The classification of arithmetic disorders has traditionally been predicated on neuropsychological features and associated learning disabilities. We assessed the compatibility of these classifications on a non-referred, population-based cohort of 139 children with developmental dyscalculia (DC). The assessment battery included reading and spelling tests, evaluation for attention deficit hyperactivity disorder (ADHD), Wechsler Intelligence Scale for Children-Revised (WISC-R), ReyOsterreith complex figure, Benton's test of facial recognition, ten-word learning test, word fluency, trail making, tapping sequence, and sequential hand movements. Arithmetic was assessed using an individually administered, standardised arithmetic battery. ADHD was assessed clinically and by questionnaires. The hypotheses tested in this study were (1) whether children with DC and disabilities in reading (R) and/or spelling (RS) had better arithmetic skills than children with DC only and (2) whether ADHD as a co-morbid diagnosis wo...