Objective To explore the characteristics of P300 of subjects with attention deficit/hyperactive disorder(ADHD).Methods 34 children with ADHD were selected as ADHD group and 32 healthy subjects were selected as the health control group.They were matched in age,gender,degree of education.The auditory Oddball paradigm was applied,the event-related long latency components (N2 and P3) from Cz and Pz were measured in each test.Results Compared with the health control group,at the Cz electrode,children with ADHD showed a significandy prolonged latency of target N2 [(277.2 ± 20.3) ms vs (259.0 ± 14.9) ms,t =3.70,P ＜ 0.01] and decreased amplitude of target P3[(4.1 ± 1.6) μμV vs (5.7 ±2.0) μμV,t =3.57,P＜ 0.01].At the Pz electrode,the patient showed a significantly prolonged latency [(342.4 ± 26.3) ms vs (324.6 ± 15.5) ms,t =3.33,P ＜ 0.01] and decreased amplitude of target P3 [(4.1 ± 1.9) μV vs (7.4 ± 2.2) μV,t =6.54,P ＜ 0.01],decreased amplitude of non-target P2 [(3.0±1.l)μμV vs (3.7 ±1.3) μV,t =2.30,P＜0.05].Conclusion This study provides direct evidence that ADHD subjects have abnormal indices of endogenous P300,which is suggested that P300 might be potentially objective indicator applied in evaluation of cognitive dysfunction in ADHD children.

Objective: To study the characteristics of P300 and topographic dist ribution mapping in obsessive-compulsive patients. Methods: The P300 and topog raphic distribution mapping were recorded in 36 patients, using a Bneuro Galileoinstrument. Results: Compared with normal subjects, the wa ve patterns of obsessi ve-compulsive patients were unstable; the frontal wave variation and dissymmetry between the two sides was 63.9%; the N2 and P3 latency was prolonged; the P2 an d P3 amplitude was decreased; the P3 topographic distribution mapping was uneven ly distributed, the normal high amplitude in the parietal region was absent. For the patient group, energy levels below grade 5 in the left brain area, the fron tal area, and for both were 42.3%, 30.3%, 15.15% respectively. Conclu sion: P300 and topographic distribution might be served as an objective index for reflectin g cognitive activity in obsessive-compulsive patients.