Global gray matter morphometry differences between children with reading disability, ADHD, and comorbid reading disability/ADHD

Abstract

Extensive, yet disparate, research exists elucidating structural anomalies in individuals with Reading Disability (RD) or ADHD. Despite ADHD and RD being highly comorbid, minimal research has attempted to determine shared patterns of morphometry between these disorders. In addition, there is no published research examining the morphometry of comorbid RD and ADHD (RD/ADHD). Hence, we conducted voxel-based morphometry on the MRI scans of 106 children, ages 8-12 years, with RD, ADHD, or RD/ADHD, and typically developing controls. We found right caudate and superior frontal regions in both RD and ADHD, along with areas specific to RD and to ADHD that are consistent with current theories on these disorders. Perhaps most importantly, we found a potential neurobiological substrate for RD/ADHD. Further, our findings illustrate both shared and specific contributors to RD/ADHD, supporting two current theories on the comorbidity of RD and ADHD, thereby facilitating future work on potential etiologies of RD/ADHD.

Are there shared neural correlates between dyslexia and ADHD? A meta-analysis of voxel-based morphometry studies

“…These results suggest that this region is worth further exploration regarding its potential relevance to ADHD and dyslexia. In fact, our confidence in this finding has increased due to a recently published paper reporting converging results [30]. Jagger-Rickels et al [30] recently published the first VBM study of comorbid dyslexia+ADHD where they compared children with dyslexia only ( N = 17), ADHD only ( N = 41), and dyslexia+ADHD ( N = 16) to controls ( N = 32).…”

“…In fact, our confidence in this finding has increased due to a recently published paper reporting converging results [30]. Jagger-Rickels et al [30] recently published the first VBM study of comorbid dyslexia+ADHD where they compared children with dyslexia only ( N = 17), ADHD only ( N = 41), and dyslexia+ADHD ( N = 16) to controls ( N = 32). They reported that regions of the right caudate showed smaller volumes in all three clinical groups, consistent with the results of this meta-analysis and the notion of the right caudate as a shared neural correlate of both disorders.…”

“…The ideal recruitment strategy for investigating the neural correlates of the dyslexia-ADHD comorbidity is to collect individuals with dyslexia, ADHD, dyslexia+ADHD, and typically developing controls. Only a few studies have taken this approach (e.g., [30, 31]). In the past, such comorbid designs have been used to document differences, not similarities, between groups.…”

Neurological deficits and comorbidity in children with reading disorder

“…Similarly, on DLWT, two stimuli are activated simultaneously through both ears and the subject has to divide his\her attention. This could possibly affect the performance of the comorbid group on these neuropsychological tasks as explained by other studies as well [13,46].…”

“…Reading-related differences in attention are of particular concern because of the high incidence of comorbidity between RD in children and ADHD [7]. Jagger-Rickels et al [13] have discovered the role of caudate and frontal regions in both RD and ADHD groups of children (aged 8-12 years) to be poorly developed then healthy controls. In addition to this, Marie-Ève Marchand-Krynski et al [14] observed predictors of sequential motor movement abilities in a sample of 215 children with dyslexia and/or ADHD and found little variation in poor visual working memory in children with dyslexia, ADHD, or both as comorbid.…”