Atypical Asymmetrical Perceptual Organization in Attention Deficit Hyperactivity Disorder: An Event-Related Potential Study on Contour Integration

Background: Perceptual organization (PO) impairment may contribute to clinical symptoms and functional deficits in attention deficit hyperactivity disorder (ADHD). Therefore, this study aimed to examine the neural mechanism of PO impairment in children with ADHD and to explore its relationship with clinical symptoms. Methods: The study included 36 children with ADHD and 36 age and gender-matched healthy controls (HC). We examined the PO in all subjects using a contour integration task combined with event-related potential recordings. ANOVA was employed to analyze group differences in P1, N1, and closure negativity (N _cl ) amplitudes. Results: The early P1 amplitudes had a significant interaction effect between the group and hemisphere, showing significantly reduced P1 amplitudes in the left hemisphere compared to the right hemisphere in the HC group. The late N _cl amplitudes also had a significant interaction effect between the group and hemisphere, indicating significantly diminished amplitudes in the ADHD group compared to the HC group in the right hemisphere. Additionally, a hemisphere effect was observed in the ADHD group, demonstrating significantly reduced N _cl amplitudes in the right hemisphere compared to the left hemisphere. There was a negative relationship between the N _cl amplitudes in the right hemisphere under difficult conditions and the inattention scores within the ADHD group. Conclusions: These findings suggest the presence of atypical asymmetrical PO in children with ADHD characterized by dysfunction in the right hemisphere. This pattern may contribute to the neuropathological mechanisms associated with ADHD and could serve as a potential target for future therapeutic interventions.