Relationship Between MOXO-D-CPT Results and Volumetric Brain MR in Attention Deficit Hyperactivity Disorder

Abstract

Objective: This study aimed to examine the multidimensional relationships between MOXO-d-CPT performance and severity profiles—attention, timing, impulsivity and hyperactivity—and regional brain volumetric and cortical thickness measures in individuals with ADHD. Methods: Thirty-eight adults with ADHD underwent MOXO-d-CPT assessment and high-resolution structural brain MRI. MOXO-d-CPT performance and severity levels were analysed in relation to 155 regional brain volumes and 110 cortical thickness measures using group-wise statistical comparisons. Results: Attention performance and severity were associated with volumetric and cortical thickness differences primarily in frontal, temporal and cerebellar regions. Timing performance was related to cerebellar and frontal volumetric measures, whereas timing severity showed limited volumetric differences without cortical involvement. Impulsivity performance demonstrated no volumetric differences but was associated with cortical thickness variations in frontal and temporal regions. Hyperactivity performance was linked to both volumetric and cortical alterations, whereas hyperactivity severity was associated exclusively with cortical thickness differences, predominantly in occipital regions (p < 0.05). Conclusion: These findings highlight distinct structural brain correlates underlying MOXO-d-CPT performance and symptom severity dimensions in ADHD, supporting a multidimensional neurobiological framework that extends beyond categorical diagnostic approaches.