Differentiating the neurobiological correlates for reading gains in children with reading difficulties with and without attention-deficit/hyperactivity disorder using fMRI.

OBJECTIVE

Reading difficulties (RD) frequently co-occur with attention-deficit/hyperactivity disorder (ADHD), and children with both RD + ADHD often demonstrate greater challenges in reading and executive functions (EF) than those with RD-only.

METHODS

This study examined the effect of a 4-week EF-based reading intervention on behavioral and neurobiological correlates of EF among 8-12 y.o. English-speaking children with RD + ADHD (n = 19), RD-only (n = 18), and typically developing children (n = 18). Behavioral and resting-state fMRI data were collected from all participants before and after 4 weeks of the EF-based reading computerized program. Group (RD + ADHD, RD-only, typical readers) x Test (pre- and post-intervention) repeated measures ANOVAs were conducted for reading, EF, and brain functional connectivity (FC) measures.

RESULTS

Across groups, reading (fluency, comprehension) and EF (inhibition, speed of processing) behavioral performance improved following the intervention. Exploratory subgroup comparisons revealed that children with RD + ADHD, but not RD-only, showed significant gains in reading comprehension, whereas inhibition improved in both RD groups, but not among typical readers. Furthermore, across groups, FC between the frontoparietal (FP) and cingulo-opercular (CO) networks decreased following the intervention. Exploratory subgroup comparisons revealed that children with RD + ADHD, but not RD-only, showed a significant decrease in FC of FP-CO and FP-dorsal attention network.

CONCLUSIONS

These results support the differential response to an EF-based reading intervention of children with RD with and without comorbid ADHD at brain and behavioral levels.