Effects Of Methylphenidate On Cognitive Function In Children With Attention Deficit Hyperactivity Disorder: An Event-related Potentials Study

Objective To investigate the changes of conflict monitoring and response inhibition in human of different age groups, and examine the neuropsychological basis of NOGO-N2 and NOGO-P3.Methods ERPs elicited in Continuous Performance Test were recorded in eighteen 8-year-old children, seventeen 11-year-old children and twenty 22-year-old undergraduates. The behavioural performance were recorded simultaneously and changes of NOGO-N2 and NOGO-P3 were analysed.Results Reaction times shorten and omission errors reduce with age,the differences have statistical significance between three groups ( P<0.05 ) ;Hit numbers increase and commission errors reduce,11-year-old group and 22-year-old group compared to 8-year-old group,the differences have statistical significance(P<0.05),but there was no significantly difference between 11-year-old group and 22-year-old group(P>0.05). Amplitude of NOGO-N2 was significantly larger than that of GO, the differences have statistical significance within the three group(sP<0.05); Amplitude of NOGO-N2 decreases with age, the differences have statistical significance between three groups(P<0.05); Amplitude of NOGO-P3 was smallest in 11-year-old group,comparing to 8-year-old group or 22-year-old group, the differences have statistical significance(P<0.05).Conclusions The results support the hypothesis of links between NoGo-N2 and conflict monitoring and NoGo-P3 and response inhibition. Attention processes developed most strongly before age 11, whereas conflict inhibition processes begin developing after age 11; Amplitude of NOGO-N2 decreases with age, Amplitude of NOGO-P3 has no distinct changes with age.Part II Effects of methylphenidate on cognitive function in children with attention deficit hyperactivity disorder:an event-related potentials studyObjective To investigate the effect of Methylphenidate on the ERP waveform of children with attention deficit hyperactivity disorder(ADHD) ,and to estimate the further curative effect of Methylphenidate on ADHD.Methods ERP elicited by cued-Continuous Performance Test were recorded before and under MPH treatment in 28 ADHD children and 28 healthy children,the behavioural performance were collected simultaneously.Based on the behavioural results, the patients were divided into two groups: responders and non-responders. To compare and analyse the changes of ERP in two groups before and under MPH treatment,and to compare to the control group.Results After medcation,the responders'amplitude of NOGO-P3 was larger(P<0.05) than that of before treatment,and was comparable to the control group(P>0.05); No significant differences were found in the amplitude of NOGO-P3 in the non- responders group,they were significantly smaller than that of the control group; The amplitude of NOGO-N2 of two groups did not have significant differences before and under MPH treatment,and had no significant differences with the control group.Off medication,there were no differences between responders and non-responders.Conclusion According to the change of the amplitude of NOGO-P3,we can use cued-CPT to forecast the further curative effect of Methylphenidate on the ADHD children.