title: Neuropsychological analyses of impulsiveness in childhood hyperactivity.
abstract: BACKGROUND
  Neuropsychological analyses of impulsiveness are needed to refine assessment of attention-deficit hyperactivity disorder (ADHD).
  
  
  OBJECTIVE
  To investigate specific impairments in hyperactive children in a neuropsychological task battery of impulsiveness, the Maudsley Attention and Response Suppression (MARS) task battery, and to identify the neural substrates.
  
  
  METHODS
  Impulsiveness was assessed using different tasks of inhibitory control and time management (MARS) in 55 children with ADHD, other diagnoses and controls. Functional magnetic resonance images were obtained from adolescents with and without ADHD during three of the tasks.
  
  
  RESULTS
  Children with ADHD, but not psychiatric controls, were impaired on tests of response inhibition, but not of motor timing. Reduced right prefrontal activation was observed in hyperactive adolescents during higher level inhibition and delay management, but not during simple sensorimotor coordination.
  
  
  CONCLUSIONS
  Attention-deficit hyperactivity disorder is characterised by specific deficits in tasks of motor response inhibition, but not motor timing, and by dysfunction of frontostriatal brain regions.
authors.affiliation: MRC Child and Adolescent Psychiatry Unit, Institute of Psychiatry, King's College, London, UK. k.rubia@iop.kcl.ac.uk
authors.forename: K
authors.initials: K
authors.lastname: Rubia
authors.forename: E
authors.initials: E
authors.lastname: Taylor
authors.forename: A B
authors.initials: AB
authors.lastname: Smith
authors.forename: H
authors.initials: H
authors.lastname: Oksanen
authors.forename: S
authors.initials: S
authors.lastname: Overmeyer
authors.forename: S
authors.initials: S
authors.lastname: Newman
authors.forename: H
authors.initials: H
authors.lastname: Oksannen
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D001927:Brain Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005625:Frontal Lobe; D006801:Humans; D007175:Impulsive Behavior / Q000175:diagnosis* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology