title: Linear and non-linear EEG analysis of adolescents with attention-deficit/hyperactivity disorder during a cognitive task.
abstract: OBJECTIVE
  We aimed to investigate whether electroencephalograph (EEG) dynamics differ in adolescents with attention-deficit/hyperactivity disorder (ADHD) compared with healthy subjects during the performance of a cognitive task.
  
  
  METHODS
  We recorded EEGs from 19 scalp electrodes in 11 adolescent boys with ADHD and 12 age-matched healthy boys while the subjects were at rest and during a continuous performance test (CPT). The approximate entropy (ApEn), a non-linear information-theoretic measure, was calculated to quantify the complexity of the EEGs.
  
  
  RESULTS
  The mean ApEn of the ADHD patients was significantly lower than the healthy subjects over the right frontal regions (Fp2 and F8) during the performance of the cognitive task, but not at rest. The spectral analysis showed significant differences between the two groups in the P3 and T4 regions at rest and the Fp2 and F8 regions during task performance.
  
  
  CONCLUSIONS
  The differences in EEG complexity between the two groups suggest that cortical information processing is altered in ADHD adolescents, and thus their levels of cortical activation may be insufficient to meet the cognitive requirements of attention-demanding tasks.
  
  
  CONCLUSIONS
  This study suggests that a non-linear measure such as ApEn is useful for investigating neural dysfunctions in adolescents with ADHD.
authors.affiliation: Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea.
authors.forename: Hansem
authors.initials: H
authors.lastname: Sohn
authors.forename: Inhye
authors.initials: I
authors.lastname: Kim
authors.forename: Wonhye
authors.initials: W
authors.lastname: Lee
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Peterson
authors.forename: Hyunju
authors.initials: H
authors.lastname: Hong
authors.forename: Jeong-Ho
authors.initials: JH
authors.lastname: Chae
authors.forename: Sayong
authors.initials: S
authors.lastname: Hong
authors.forename: Jaeseung
authors.initials: J
authors.lastname: Jeong
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology*; D003071:Cognition / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods* / Q000706:statistics & numerical data*; D006801:Humans; D016014:Linear Models; D008297:Male; D017711:Nonlinear Dynamics; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology