title: Intelligence moderates impulsivity and attention in ADHD children: an ERP study using a go/nogo paradigm.
abstract: OBJECTIVE
  If the cardinal symptoms of ADHD - hyperactivity, impulsivity and inattention - are combined with a learning disability (70 ≥ IQ < 85), the question arises whether a child shows hyperkinetic behaviour because of intellectual overload in a challenging situation, for example at school. Perhaps, this behaviour is not a primary attention deficit disorder but an impulse control disorder, determined by the primarily intelligence level. It raised the question whether attention deficit and impulse control regarded as behavioural inhibition deficit may depend on intelligence and therefore should be separated into distinct clinical entities.
  
  
  METHODS
  A total of 45 children (15 with ADHD, 15 with learning disabilities (LD), 15 with ADHD and learning disabilities) were compared in a matched-pair design with 42 control children using a go/no go paradigm (visual continuous performance test, CPT). The dependent variable was the target P3 amplitude, averaged from a 10-20 EEG measurements under distinct trigger conditions. For statistical analysis, a three-factor analysis of variance (MANOVA) with repeated measurements was used. In a subsequent regression analysis with residuals, the influence of intelligence (IQ) was calculated and a "parallel analysis of variance" was conducted.
  
  
  RESULTS
  No differences in the P3 amplitudes in the comparison ADHD-control group were found. Reduced P3 amplitudes as main effects in the LD group compared with controls were found and a significant group-dependent interaction on reduced P3 amplitudes comparing ADHD + LD versus control group. Using residuals (IQ), this interaction was not longer verifiable.
  
  
  CONCLUSIONS
  Impulsivity and attention deficit as the cardinal symptoms of ADHD, regarded as behavioural inhibition deficit, are essentially moderated by the primary intelligence, rather than by an attention deficit. The lower the IQ, the more ADHD surfaces as a disturbed impulsivity and lesser as an attention deficit.
authors: Department of Child- and Adolescence Psychiatry, Neurology, Psychosomatics and Psychotherapy, University of Rostock, Rostock, Germany. johannes.buchmann@med.uni-rostock.de
authors: Johannes
authors: J
authors: Buchmann
authors: Wolfgang
authors: W
authors: Gierow
authors: Olaf
authors: O
authors: Reis
authors: Frank
authors: F
authors: Haessler
mesh_terms: D001288:Attention / Q000502:physiology; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D003118:Color Perception / Q000502:physiology*; D015897:Comorbidity; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D007175:Impulsive Behavior / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D007266:Inhibition, Psychological; D007360:Intelligence / Q000502:physiology*; D007859:Learning Disabilities / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D008297:Male; D016555:Matched-Pair Analysis; D009483:Neuropsychological Tests; D010296:Parietal Lobe / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology*; D012815:Signal Processing, Computer-Assisted; D013702:Temporal Lobe / Q000503:physiopathology