title: Electroencephalogram complexity analysis in children with attention-deficit/hyperactivity disorder during a visual cognitive task.
abstract: OBJECTIVE
  The aim of this study was to investigate electroencephalogram (EEG) dynamics using complexity analysis in children with attention-deficit/hyperactivity disorder (ADHD) compared with healthy control children when performing a cognitive task.
  
  
  METHODS
  Thirty 7-12-year-old children meeting Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) criteria for ADHD and 30 healthy control children underwent an EEG evaluation during a cognitive task, and Lempel-Ziv complexity (LZC) values were computed. There were no significant differences between ADHD and control groups on age and gender.
  
  
  RESULTS
  The mean LZC of the ADHD children was significantly larger than healthy children over the right anterior and right posterior regions during the cognitive performance. In the ADHD group, complexity of the right hemisphere was higher than that of the left hemisphere, but the complexity of the left hemisphere was higher than that of the right hemisphere in the normal group.
  
  
  CONCLUSIONS
  Although fronto-striatal dysfunction is considered conclusive evidence for the pathophysiology of ADHD, our arithmetic mental task has provided evidence of structural and functional changes in the posterior regions and probably cerebellum in ADHD.
authors.affiliation: a Psychiatry & Psychology Research Center , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Zarafshan
authors.affiliation: a Psychiatry & Psychology Research Center , Tehran University of Medical Sciences , Tehran , Iran.|b Department of Biomedical Engineering , Science and Research Branch, Islamic Azad University , Tehran , Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Khaleghi
authors.affiliation: a Psychiatry & Psychology Research Center , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Mohammadi
authors.affiliation: a Psychiatry & Psychology Research Center , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Moeini
authors.affiliation: a Psychiatry & Psychology Research Center , Tehran University of Medical Sciences , Tehran , Iran.
authors.forename: Nastaran
authors.initials: N
authors.lastname: Malmir
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications* / Q000175:diagnosis / Q000473:pathology; D001931:Brain Mapping; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D015999:Multivariate Analysis; D010775:Photic Stimulation; D014796:Visual Perception / Q000502:physiology*
keywords: Attention-deficit/hyperactivity disorder; cognitive task; electroencephalogram; lempel–ziv complexity; mental activity