Neuropediatrics 2006; 37 - TP99
DOI: 10.1055/s-2006-945692

ANALYSIS OF N200-P300 COMPLEX IN VISUAL ODDBALL PARADIGM: AMPLITUDE DIFFERENCE BETWEEN ADHD AND NORMAL CONTROL

M Kaga 1, Y Inoue 1, N Kokubo 1, A Ishiguro 1, A Gunji 1, M Inagaki 1
  • 1Department of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry (NCNP), Japan, Kodaira, Tokyo, Japan

Objectives: It has been reported that ADHD patients have reduced amplitude of P300 in response to target stimuli (TS) of oddball paradigm, while changes of P300 component to non-target stimuli (NT) have not been discussed yet. Present study will show the difference in N200 and P300 complex (NPC) to TS and NT between ADHD and control subjects.

Methods: We recruited 10 healthy children and 10 children with combined type of ADHD, who had been diagnosed based on DSM-IV criteria, between 7 and 11 years of age. A pair of 2 Kanji characters was presented with 20% occurrence of TS. EEG at 4 scalp sites (Fz, Cz, Pz and Oz) was averaged 10 epochs, which were defined as 100ms pre-stimulus to 900ms post-stimulus onset, and NPC peak amplitude was determined and analyzed for all subjects.

Results: NPC to TS was dominant at Pz site in control subjects, whereas it was greater at Cz in ADHD subjects. These differences did not reach statistical significance (ANOVA). In response to NT, ADHD subjects showed significant decrease in NPC amplitude at Cz site compared with control subjects (p<0.01).

Conclusion: There was no significant frontocentral maximization of N200/P300 complex to non-target stimuli, which had been reported in various studies of Go/NoGo task of adult subjects. This finding may be due to immaturity of frontal lobe function in younger subjects and/or larger number of nontarget stimuli in the paradigm. Significant reduction in N200/P300 complex to non-target stimuli in ADHD children may imply the dysfunction of inhibitory processing in this disorder.