Our literature review identified ANS dysfunction in individuals with ADHD , more often in the direction of hypo-arousal than hyper-arousal , particularly at rest and during tasks requiring response regulation and sustained attention .
Stimulant medications  increased ANS activity and , in some studies , reinforcers and rewards produced a similar effect , suggesting that ANS function can be modified in ADHD .
Although arousal mechanisms have frequently been found to be atypical in ADHD , these findings usually emerged from indirect behavioural measures which give only a limited underst and ing of arousal dysregulation in this condition .
Methylphenidate effects in attention deficit/hyperactivity disorder: electrodermal and ERP measures during a continuous performance task
Rationale Previous research investigating the effects of stimulants , such as methylpheni date ( MPH ) , on children with attention deficit/hyperactivity disorder ( AD/HD ) has rarely included autonomic measures of arousal . Objective Our aim was to clarify the effects of MPH on central and autonomic measures in AD/HD children during a continuous performance task ( CPT ) using a naturalistic open-label study . Method Thirty-six boys ( 18 AD/HD and 18 control ) participated in a CPT over two trial periods , allowing a more valid estimate of the effects of medication , rather than assuming that retesting per se has no substantial impact . MPH was administered to the AD/HD group 1 h prior to the second trial . Errors and reaction time ( RT ) were recorded as measures of performance , electrodermal activity as an autonomic nervous system measure and event-related potentials ( ERPs ) as an index of central nervous system activity . Results AD/HD children made more errors than controls in the first session , but no group differences were found after medication . No significant differences were observed for RT . Skin conductance level was found to be lower in AD/HD children than controls , but this difference was also ameliorated after medication . Conversely , mean skin conductance response to target stimuli was found not to differ between groups during the initial test phase but became significantly different in phase 2 . ERP data showed topographic differences between groups in N1 , P2 , N2 and P3 at the initial test phase , which were reduced at the second test . ConclusionS timulant medication ameliorated some of the dysfunctions in AD/HD children , which are reflected in behavioural and ERP measures . These results , in combination with general differences in electrodermal activity , support a hypoarousal model of AD/HD , which can explain the action of MPH in these children
Our literature review identified ANS dysfunction in individuals with ADHD , more often in the direction of hypo-arousal than hyper-arousal , particularly at rest and during tasks requiring response regulation and sustained attention .
Stimulant medications  increased ANS activity and , in some studies , reinforcers and rewards produced a similar effect , suggesting that ANS function can be modified in ADHD .
Although arousal mechanisms have frequently been found to be atypical in ADHD , these findings usually emerged from indirect behavioural measures which give only a limited underst and ing of arousal dysregulation in this condition .