Objective To investigate the correlations of intelligence level and cognitive function with electroencephalogram abnormalities in children with Attention Deficit Hyperactivity Disorder (ADHD).

Methods A total of 85 children with ADHD were enrolled as ADHD group, and another 82 healthy children who underwent physical examinations during the same period were selected as control group. Both groups underwent electroencephalogram examinations and were assessed for intelligence level and cognitive function using the Chinese-Wechsler Intelligence Scale for Children (C-WISC) and Wisconsin Card Sorting Test (WCST), respectively. Pearson correlation analysis was conducted to explore the correlations of the C-WISC and WCST assessment results with the probability of EEG abnormalities in children with ADHD.

Results Children in the ADHD group exhibited higher incidence of irregular α waves, increased β rhythm, increased θ waves, increased δ waves, epileptiform discharges, and a higher overall abnormal rate in electroencephalogram compared to those in the control group (P < 0.05). C-WISC assessment results showed that the Verbal Intelligence Quotient (VIQ), Performance Intelligence Quotient (PIQ), and Full-Scale Intelligence Quotient (FIQ) of children in the ADHD group were lower than those in the control group (P < 0.05). According to the electroencephalogram results, children with ADHD were further divided into abnormal group of 41 cases and normal group of 44 cases. The VIQ, PIQ, and FIQ of children in the abnormal group were lower than those in the normal group(P < 0.05). The WCST assessment results showed that the number of categories completed by children in the ADHD group was lower than that of the control group, while the number of error responses, perseverative errors, and perseverative responses were higher than those in the control group (P < 0.05). The VIQ, PIQ, FIQ, and number of categories completed in children with ADHD were negatively correlated with the probability of EEG abnormalities (r=-0.421, -0.462, -0.561, -0.403, P < 0.05).

Conclusion Some children with ADHD exhibit electroencephalogram abnormalities, decreased intelligence levels, and impaired cognitive function, and the probability of electroencephalogram abnormalities is negatively correlated with the intelligence level and cognitive function of children with ADHD.