Prefrontal and frontostriatal structures mediate academic outcomes associated with ADHD symptoms

• Main Authors: Howard Chiu, Sila Genc, Charles B. Malpas, Emma Sciberras, Jan M. Nicholson, Daryl Efron, Timothy J. Silk
• Format: Article
• Language: English
• Published: Elsevier 2021-12-01
• Series: Brain Disorders
• Subjects: ADHD; Academic achievement; Working memory; Frontostriatal; Prefrontal
• Online Access: http://www.sciencedirect.com/science/article/pii/S2666459321000226

Children with attention-deficit/hyperactivity disorder (ADHD) have poor academic functioning compared to typically developing children, with executive dysfunction mediating the relationship between ADHD symptoms and academic outcomes. This study investigated whether differences in prefrontal and frontostriatal structures explain this mediating relationship. 132 children aged 9–11 years (mean 10.4 years) completed a MRI including structural and diffusion acquisitions. Cortical regions were parcellated using Freesurfer. Frontostriatal tracts were generated using constrained spherical deconvolution (CSD) tractography. Executive functioning was assessed using working memory, sustained attention and response inhibition tasks. Academic achievement was measured by direct assessment of reading and mathematics, teacher report of academic competence, and national standardized academic testing. Serial mediation analysis tested whether executive function and frontostriatal structures mediate the poorer academic functioning seen in ADHD. Symptom severity (predominantly inattention) was associated with poorer academic outcomes. Working memory partially mediated the relationship between symptoms and academic outcomes. In a serial mediation model, left DLPFC volume, right orbitofrontal volume, and left striatal structures to DLPFC tract volumes partially mediated academic outcome. This study suggests that variability in frontostriatal structures explain the mediating effect of cognitive performance on the relationship between ADHD symptomatology and academic outcomes.