Abstract
OBJECTIVE: Motor control difficulties are highly common in Attention-Deficit/Hyperactivity Disorder (ADHD), yet the etiology of this comorbidity remains unclear. We examined (1) whether children with ADHD have atypical movement-related cortical potentials (MRCPs) during movement preparation and/or execution compared to typically developing (TD) children, and (2) whether MRCPs associated with visual-motor performance and ADHD symptoms overlap. METHODS: MRCPs and visual-motor integration (VMI) were measured among 66 right-handed children with ADHD and 30 TD children (ages 7-11 years). Caregivers reported on ADHD symptoms. MRCPs were extracted over fronto-central scalp regions during two ERP tasks requiring button presses. RESULTS: Children with ADHD had lower accuracy on MRCP tasks and reduced VMI scores, compared to TDs. ADHD diagnosis was associated with attenuated correct trial MRCP amplitudes at a fronto-midline electrode during movement preparation, but not execution. ADHD symptom severity and reduced error trial MRCP amplitudes each explained unique variance in VMI performance. CONCLUSIONS: Pediatric ADHD is associated with atypical cortical activity during movement preparation, but not execution. VMI performance and ADHD diagnosis were associated with distinct motor cortical processes, providing support for the separate etiology hypothesis. SIGNIFICANCE: Motor difficulties in children with ADHD may require an intervention approach that is distinct from the treatment of core ADHD symptoms.