On the automaticity/cerebellar deficit hypothesis of dyslexia: balancing and continuous rapid naming in dyslexic and ADHD children.

The present study examined the relationship of reading disability (RD) and attention deficit hyperactivity disorder (ADHD) to balancing problems. In the cerebellar deficit hypothesis of dyslexia of Nicolson et al. [Trends Neurosci. 24 (2001) 508], balancing problems are taken as sign of a cerebellar deficit and were found to be associated with dyslexia. Four groups of 10 children each, representing all combinations of RD (absent versus present) and ADHD (absent versus present), were included. However, poor balancing (assessed both singly and together with a secondary task) was not found to be associated with RD, but with ADHD. In contrast, poor performance on continuous rapid naming tasks (digit and color naming) was found to be associated with RD and not with ADHD.