Response Variability in Children With Attention Deficit Hyperactivity Disorder (ADHD)
Condition: Attention Deficit Hyperactivity Disorder
MeSH terms: Hyperkinesis; Attention Deficit Disorder with Hyperactivity
Study type: Interventional
Phase: Phase 4

Summary: 
      Children with Attention Deficit Hyperactivity Disorder (ADHD) have numerous areas of
      neuropsychological dysfunction including response inhibition, working memory, and attention.
      One neuropsychological outcome measure that consistently reveals between-group differences is
      response variability. However, until recently, differences in response variability have been
      reported as an ancillary finding or viewed as a nuisance in the analyses. The specific aims
      of the present study are to 1) Examine response variability in ADHD patients across
      neuropsychological tasks to understand the breadth of this specific deficit and to understand
      the relation between response variability and other neuropsychological outcome measures; 2)
      Assess whether response variability deficits are specific to either or both of the two most
      prevalent ADHD subtypes (i.e., Combined Type [CT] and Predominantly Inattentive Type [PIT]);
      3) Determine whether response variability in ADHD patients is affected by either medication
      or a variety of environmental manipulations (e.g., reward); and 4) Understand the
      relationship between neuropsychological measures of response variability and naturalistic
      instances of variable performance. Forty-five children (aged 7-11) with ADHD-CT, 45 children
      with ADHD-PIT, and 45 normal controls will be recruited to examine response variability
      across a wide range of neuropsychological tests. Task parameters such as event rate, stimulus
      saliency, and the presence of operant reward will be modified on each test to determine the
      conditions under which response variability is manifested in children with ADHD. In addition,
      all children with ADHD will participate in a placebo-controlled, randomized medication trial
      with a psychostimulant medication to assess the effects of medication on response
      variability. Advanced analytic methods utilizing non-Gaussian distributions and fast Fourier
      Transforms of the reaction time data will be used to conduct detailed analyses of RT patterns
      across the ADHD and normal control groups. Further, the effects of task parametric
      manipulations and medication on response variability will be examined. Finally, relations
      between response variability on neuropsychological tests and response variability in a
      variety of real-world analog situations will be examined to evaluate the ecological validity
      of these deficits.
    


Intervention name(s): Methylphenidate; placebo; Methylphenidate; Methylphenidate
Intervention type(s): Drug; Drug; Drug; Drug
Intervention description(s): 18 mg methylphenidate; Placebo; 36 mg methylphenidate; 54 mg methylphenidate
Other intervention name(s): Concerta; Concerta; Concerta
Intervention MeSH terms: Methylphenidate
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Health Services Research