ABSTRACT
<p><b>OBJECTIVE</b>To investigate the cognitive characteristics in early school-age children with attention deficit hyperactivity disorder (ADHD) using event-related potential (ERP) and Achenbach Child Behavior Checklist (CBCL), as well as the correlation between ERP and behavioral problems.</p><p><b>METHODS</b>A total of 22 children aged 6-7 years with ADHD and 19 healthy children matched by age were enrolled. Continue Performance Test-AX (CPT-AX) was performed for ERP test. The amplitude and latency of N2 and P3 of Go and Nogo were compared. The CBCL was completed by the parents, and the correlation between behavioral factors and ERP was analyzed.</p><p><b>RESULTS</b>The ADHD group had a significantly higher number of ERP omissions than the normal control group (10±8 vs 5±4; P<0.05), while the reaction time and number of commission errors showed no significant differences between the two groups (P>0.05). The ADHD group showed a significantly lower Go-N2 amplitude than the normal control group (-8±5 μV vs -10±4 μV; P<0.05). In the ADHD group, the detection rates of hyperactivity, attack, and discipline violation were 27%, 27% and 9% respectively. The scores on attack and discipline violation subscales were negatively correlated with the Go-N2 amplitude of ERP (r=-0.43 and -0.48 respectively; P<0.05), while the score on hyperactivity subscale was positively correlated with the latency of Go-P3 (r=0.50, P<0.05).</p><p><b>CONCLUSIONS</b>The early school-age children with ADHD show the tendency to the impairment of attention/executive function, but the inhibition function defect has not been noted. In early school-age children with ADHD, the behavioral problems such as hyperactivity, attack, and discipline violation are associated with ERP.</p>