title: EEG evidence for a new conceptualisation of attention deficit hyperactivity disorder.
abstract: OBJECTIVE
  This study investigated the presence of electroencephalographic (EEG) clusters within a sample of children with the inattentive type of attention-deficit/hyperactivity disorder (ADHD).
  
  
  METHODS
  Subjects consisted of 100 boys with ADHD and 40 age-matched controls. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and relative power in the delta, theta, alpha and beta bands. Factor analysis was used to group sites into 3 regions; frontal, central and posterior. These data were subjected to cluster analysis.
  
  
  RESULTS
  Two distinct EEG clusters of children with the inattentive type of ADHD were found. These were characterised by (a) increased high-amplitude theta with deficiencies of delta and beta activities, and (b) increased slow wave and deficiencies of fast wave activity.
  
  
  CONCLUSIONS
  These two subtypes are independent of current diagnostic categories, and consist of a cortically hypoaroused group and a group typified by a maturational lag in central nervous system (CNS) development. These results support a re-conceptualisation of ADHD based on the CNS abnormality underlying the disorder rather than the behavioural profile of the child. This has the potential to add a level of predictive validity, which is currently lacking in the present diagnostic systems.
authors.affiliation: Brain and Behaviour Research Institute, University of Wollongong, Australia. adam_clarke@uow.edu.au
authors.forename: Adam R
authors.initials: AR
authors.lastname: Clarke
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Barry
authors.forename: Rory
authors.initials: R
authors.lastname: McCarthy
authors.forename: Mark
authors.initials: M
authors.lastname: Selikowitz
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D001143:Arousal / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis* / Q000523:psychology; D002648:Child; D016000:Cluster Analysis; D004566:Electrodes; D004569:Electroencephalography / Q000706:statistics & numerical data*; D005163:Factor Analysis, Statistical; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales