Arousal-state modulation in children with AD/HD.
OBJECTIVE
To investigate the effect of arousal-state modulation, via manipulation of stimulus event-rate, on response inhibition in children with Attention-Deficit/Hyperactivity disorder (AD/HD) using behavioural and ERP measures.


METHODS
Eighteen children with AD/HD, aged 7-14years, and 18 age-and sex-matched controls performed a cued visual Go/Nogo task (70% Go) with stimuli presented at fast, medium and slow event-rates. Task performance and ERPs to Warning, Go and Nogo stimuli, as well as preparation between the S1-S2 interval, were examined for group differences.


RESULTS
AD/HD subjects displayed poorer response inhibition during the fast condition, accompanied by a reduced Nogo P3. Group differences during the fast rate extended to Warning cues, with the AD/HD group showing ERP evidence of atypical orienting/preparation, as indexed by the early and late CNV, and early sensory/attentive processing prior to S2.


CONCLUSIONS
Although deficient response inhibition has been proposed as the core deficit in AD/HD, the results of the present study highlight the key role of energetic factors. Furthermore, group differences found to cues suggest that this effect extends to the processing of task-irrelevant stimuli.


CONCLUSIONS
This was the first ERP Go/Nogo task investigation using three event-rates, and the results support the theory that state factors may contribute to response inhibition deficits in AD/HD.
Benikos
Nicholas
N
School of Psychology, Brain & Behaviour Research Institute, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.
Johnstone
Stuart J
SJ
D000293:Adolescent; D000704:Analysis of Variance; D001143:Arousal / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D002648:Child; D003463:Cues; D004192:Discrimination, Psychological; D004569:Electroencephalography / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology