Reading and dual-task balancing: evidence against the automatization deficit explanation of developmental dyslexia

Nicolson and Fawcett (1990) demonstrated specifically impaired balancing performance of children with dyslexia when balancing had to be done simultaneously with a secondary task. This finding was taken as evidence for a general automatization deficit of children with dyslexia. We attempted to replicate this finding with German children with dyslexia, whose characteristic reading difficulty is a fluency problem quite in correspondence with the automatization deficit explanation. Because we were concerned about a potential confound between dyslexia and attention-deficit/hyperactivity disorder (ADHD), we also collected teacher ratings on ADHD symptoms. We found that poor dual-task balancing was limited to children with higher ADHD ratings and that children with dyslexia without higher ADHD ratings performed as well on dual-task balancing as age-matched control children. This finding supports the aforementioned confound. Together with other findings from our research group, it supports the position that, even in consistent orthographies, difficulties in learning to read are caused by a specific phonological deficit.