Developmental dyscalculia and down syndrome: indicative evidence

This study investigated the hypothesis that developmental dyscalculia is part of the behavioural phenotype of Down syndrome. One hundred and fifty-one individuals with Down syndrome across three age groups contributed data. These age groups were: 6–8 years (n = 41); 13–15 years (n = 70); and 20–22 years (n = 40). Data were collected using the Stanford-Binet (Fourth Edition) and age equivalent scores on the Pattern Analysis and Quantitative subscales were used in the analyses. A repeated measure ANOVA showed a significant difference between performances on the two subtests with an interaction with age group. While performance on Pattern Analysis was better than on Quantitative for all groups the difference was most marked for the oldest group. Approximately 66% of the participants had a higher age equivalent score on the Pattern Analysis subscale than on the Quantitative subscale. It appears to be plausible that developmental dyscalculia contributes to the behavioural phenotype of Down syndrome and further investigation of this proposition is warranted.