title: Responses to methylphenidate in adolescent AD/HD: evidence from concurrently recorded autonomic (EDA) and central (EEG and ERP) measures.
abstract: This paper aims to examine the effects of methylphenidate (MPH) on integrated baseline and event-related psychophysiological measures in AD/HD. Thirty-four unmedicated AD/HD adolescents (11-17 years; 6 females) were first compared to 34 age- and sex-matched controls, and then re-tested at least 4 weeks after methylphenidate (MPH) medication. In each testing session, EDA was recorded simultaneously with EEG during a resting eyes open condition, and with ERPs during an auditory oddball task. Unmedicated AD/HD subjects were compared to controls and then AD/HD subjects were compared pre- and post-medication. Correlations between the change in EEG theta and the remaining psychophysiological variables were undertaken to provide information about post MPH treatment changes. In the unmedicated state, AD/HD was characterized by abnormally enhanced theta, across fronto-central sites, generally reduced P2 responses, with larger non-specific and oddball-elicited SCRs and poor behavioural performance on the oddball task. Following treatment, AD/HD showed a 'normalization' of theta activity (particularly in the right hemisphere), a reduction in the rate of decrement of EDA and a general increase in P3 amplitude. These findings suggest that methylphenidate is associated with a robust 'normalization' of low frequency EEG activity during the resting brain state, but has less impact on task-related brain activity or phasic changes in autonomic function. This dissociation of resting and task-related activity may prove to be useful in elucidating the effects of stimulant versus new non-stimulant medications in AD/HD.
authors.affiliation: The Brain Dynamics Centre, University of Sydney, Westmead Hospital, Australia. dher5793@mail.usyd.edu.au
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Hermens
authors.forename: Leanne M
authors.initials: LM
authors.lastname: Williams
authors.forename: Simon
authors.initials: S
authors.lastname: Clarke
authors.forename: Michael
authors.initials: M
authors.lastname: Kohn
authors.forename: Nicholas
authors.initials: N
authors.lastname: Cooper
authors.forename: Evian
authors.initials: E
authors.lastname: Gordon
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D000697:Central Nervous System Stimulants / Q000008:administration & dosage*; D002648:Child; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005074:Evoked Potentials, Visual / Q000187:drug effects*; D005260:Female; D007839:Functional Laterality / Q000187:drug effects; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000008:administration & dosage*; D013826:Theta Rhythm / Q000187:drug effects*
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate