A study of reading disorder comorbid with pervasive developmental disorder or attention-deficit/hyperactivity disorder

Objective: We investigated the frequency and characteristics of reading disorder comorbid with pervasive developmental disorder (PDD) or attention-deficitlhyperactivity disorder (AD/HD). Methods: Articulation times and reading errors were evaluated using four Japanese reading tasks (a monomoraic syllable reading task, a word reading task, a non-word reading task, and a short Sentence reading task) in 31 children with PDD (22 boys and 9 girls) aged 6-14 years (average 9.5 years) and 39 children with AD/HD (33 boys and 6 girls) aged 6-12 years (average 9.6 years). Poor readers (PRs) were identified when articulation times were significantly longer than those of typically-developing children (≥2.0 SD) for two or more reading tasks, and non-PRs were identified when articulation times were within normal range (<2.0 SD) for all reading tasks. Results: Eight children with PDD (25.8%) and 17 children with AD/HD (43.6%) were identified as PRs. For 13 of the 70 subjects, the chief complaints were difficulties in reading and writing words at their first Visit to our hospital. All 13 of these subjects had AD/HD, and twelve of these were additionally identified as PRs. Among the remaining 26 children with AD/HD, five (19.2%) were identified as PRs. In AD/HD children, PRs made significantly more reading errors and had lower lQ scores than did non-PRs, but in PDD children, there were no significant differences between these two groups regarding IQ or reading errors. An analysis using the Clinical-Symptoms-Checklist for Reading and Writing Words revealed that PRs in our study showed difficulties in reading words in daily life. Conclusions: PRs in our study had reading disorders, which would, in turn, mean that reading disorder was often comorbid with PDD or AD/HD. These results strongly indicate the necessity of testing for the presence of reading disorder in children with PDD or AD/HD.