title: Coherence in children with Attention-Deficit/Hyperactivity Disorder and excess beta activity in their EEG.
abstract: OBJECTIVE
  This study investigated differences in coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (ADHD) - with the typical EEG profile (increased theta and decreased beta activity), and with excess beta activity - and a normal control group.
  
  
  METHODS
  Thirty-four children with ADHD were included in each of the typical and excess beta groups, and were age and sex matched with 34 control subjects. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric and eight interhemispheric electrode pairs, for the delta, theta, alpha and beta bands.
  
  
  RESULTS
  In comparison to the controls, the typical ADHD group primarily had increased intrahemispheric theta and beta coherence at short-medium inter-electrode distances, and increased interhemispheric coherence for theta in the frontal and central/parietal/occipital regions. Their laterality effect for interhemispheric short-medium inter-electrode distances was reduced in the theta band. Differences between the excess beta group and the control group were primarily found in laterality of the intrahemispheric theta coherence at short-medium electrode distances, and increased interhemispheric theta coherence in the frontal regions. Reduced delta coherence in the temporal regions was also found.
  
  
  CONCLUSIONS
  These results suggest that ADHD children with excess beta power have an underlying brain dysfunction in the frontal lobes which is found in common with children with the typical EEG profile. However a number of qualitative differences exist which could be associated with other aspects of the ADHD diagnosis or another comorbid condition.
  
  
  CONCLUSIONS
  This is the first study to investigate EEG coherence in ADHD children who have increased beta power.
authors.affiliation: Brain & Behaviour Research Institute and School of Psychology, University of Wollongong, 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: Stuart J
authors.initials: SJ
authors.lastname: Johnstone
authors.forename: Ching-I
authors.initials: CI
authors.lastname: Hsu
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Magee
authors.forename: Carlie A
authors.initials: CA
authors.lastname: Lawrence
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Croft
mesh_terms: D000513:Alpha Rhythm / Q000706:statistics & numerical data; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000503:physiopathology*; D001611:Beta Rhythm / Q000706:statistics & numerical data*; D002540:Cerebral Cortex / Q000503:physiopathology; D002648:Child; D003627:Data Interpretation, Statistical; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D013826:Theta Rhythm / Q000706:statistics & numerical data