The mediating effects of rapid automatized naming on children's inattention symptoms and word-reading ability

Attention Deficit/Hyperactivity Disorder (ADHD) and Reading Disability (RD) are among the most common childhood disorders (American Psychiatric Association, 2000) and co-occur significantly more frequently than expected by chance (Dykman & Ackerman, 1991; Semrud-Clikeman et al., 1992). Similar processing deficits are seen in children with ADHD and children with RD, one of which is rapid automatized naming (RAN) (Denckla & Cutting, 1999). These continuous performance tasks require quick naming of visually represented stimuli. Uncertainty about what RAN actually measures, however, makes drawing conclusions about relations to ADHD and RD difficult (Tannock, 1998). By better understanding the cognitive processes involved in RAN, and how those processes relate to ADHD and RD symptoms, the relations among RAN, ADHD, and RD might be better understood.

The current study sought to identify variables that would help explain ADHD and RD children’s difficulty with RAN. Five fundamental, neurocognitive skills were hypothesized to be related to RAN performance, ADHD, and reading disability. The effect of children’s phonological awareness, processing speed, working memory, fine-motor speed, and reaction time on their RAN performances was measured. The extent to which these same variables were related to inattention symptoms severity and word-reading ability was also assessed. Finally, the extent to which RAN mediated the effects of neurocognitive skills on inattention symptoms and word-reading ability was measured. By simultaneously measuring the hypothesized relations among variables, the processing deficits responsible for ADHD and RD children’s problems on RAN may be revealed.

Structural equation modeling was used to analyze assessment data (i.e., neurocognitive, RAN, and word-reading performance scores; parent-report of inattention symptoms) of 183 children who received neuropsychological evaluations. Results indicated the following significant direct effects: phonological awareness and working memory on word-reading ability, processing speed and working memory on RAN, and RAN on word-reading ability. A possible significant mediation effect of processing speed on word-reading ability through RAN was also shown. Significant effects of study variables on inattention symptoms were not shown, which limited conclusions about RAN’s relation to ADHD. Results are of practical importance in RD assessment because the relation between RAN and word-reading ability was shown to involve processes beyond phonology.