Brain Imaging in Children With AD/HD
Condition: Attention Deficit Disorder With Hyperactivity; Healthy
MeSH terms: Hyperkinesis; Attention Deficit Disorder with Hyperactivity
Study type: Observational

Summary: 
      The purpose of this study is to use brain imaging technology to study the connections between
      brain regions in children with attention deficit hyperactivity disorder (AD/HD), and
      comparing them to children without AD/HD.

      This study will build upon previous brain imaging studies of healthy volunteers and children
      who have AD/HD. This study will use diffusion tensor magnetic resonance imaging (DT-MRI) to
      visualize and measure certain parts of the brains of identical twin pairs in which one twin
      has AD/HD, combined type.

      Participants in this study will be screened with questionnaires and interviews, psychometric
      testing, and a physical examination. Participants' medical and educational records may be
      reviewed. Participants will undergo an MRI scan of the brain. Prior to the MRI, participants
      will have a training session in a simulated MRI scanner to learn how to lie still during MRI
      scanning. Participants may be asked to return for a follow-up scan in about 2 years.
    

Detailed description: 
      Attention-deficit/hyperactivity disorder (ADHD) is the most common childhood psychiatric
      disorder, present in between 3 to 10% of children in the United States (Wender et al 2001).
      It is thought to reflect subtle anomalies in the central nervous system and thus structural
      neuroimaging has been used extensively to delineate the neurobiology of the disorder.
      Magnetic resonance imaging has demonstrated structural anomalies in ADHD, affecting all the
      major lobes with particularly severe volume reductions in the cerebellum and relative
      preservation of the caudate nucleus (for a review see Durston 2003). In structural
      neuroimaging work, studies with monozygotic twins who are discordant for the disorder have
      proved a particularly powerful tool, with findings of a significantly smaller caudate nucleus
      in the affected twin compared to the unaffected, but genetically identical, twin (Castellanos
      et al 2003). We have previously reported an overall reduction in white matter volume in all
      four major brain lobes, with the deficit appearing to be fixed and non-progressive. However,
      recent advances in neuroimaging of white matter make feasible an examination of white matter
      characteristics, such as the degree of myelination and the coherence of white matter tracts.
      The proposed project builds on our anatomic magnetic resonance imaging (MRI) studies that
      have been performed with a 1.5-Tesla scanner in children who have
      Attention-Deficit/Hyperactivity Disorder (ADHD) and normal controls. We now propose to use
      diffusion tensor magnetic resonance imaging (DT-MRI) as conventional T(1)- and T(2)-weighted
      images at 3-Tesla to visualize and quantify white matter tracts in the brains of normal
      monozygotic (MZ) twins, MZ twins who are concordant for ADHD, and MZ twins who are discordant
      for ADHD. Ages will range from 6 to 21 years. Our principal focus will be on development and
      possible abnormalities of white matter tracts linking prefrontal-striatal-thalamic circuits
      in which we hypothesize disruption of these tracts in affected twins relative to their
      healthy co-twins. We will also explore the usefulness of this technique in delineating white
      matter in cerebellar circuits and characterize the normal development of white matter from
      ages 6 to 21 by using a single healthy twin per family.
    

Keywords: Magnetic Resonance Imaging; Diffusion Tensor Imaging; Twin Study; Attention Deficit Hyperactivity Disorder; Normal Volunteers