title: Development of cortical surface area and gyrification in attention-deficit/hyperactivity disorder.
abstract: BACKGROUND
  Delineation of the cortical anomalies underpinning attention-deficit/hyperactivity disorder (ADHD) can powerfully inform pathophysiological models. We previously found that ADHD is characterized by a delayed maturation of prefrontal cortical thickness. We now ask if this extends to the maturation of cortical surface area and gyrification.
  
  
  METHODS
  Two hundred thirty-four children with ADHD and 231 typically developing children participated in the study, with 837 neuroanatomic magnetic resonance images acquired longitudinally. We defined the developmental trajectories of cortical surfaces and gyrification and the sequence of cortical maturation, as indexed by the age at which each cortical vertex attained its peak surface area.
  
  
  RESULTS
  In both groups, the maturation of cortical surface area progressed in centripetal waves, both lateral (starting at the central sulcus and frontopolar regions, sweeping toward the mid and superior frontal gyrus) and medial (descending down the medial prefrontal cortex, toward the cingulate gyrus). However, the surface area developmental trajectory was delayed in ADHD. For the right prefrontal cortex, the median age by which 50% of cortical vertices attained peak area was 14.6 years (SE = .03) in ADHD, significantly later than in typically developing group at 12.7 years (SE = .03) [log-rank test χ(¹)² = 1300, p < .00001]. Similar, but less pronounced, delay was found in the left hemispheric lobes. There were no such diagnostic differences in the developmental trajectories of cortical gyrification.
  
  
  CONCLUSIONS
  The congruent delay in cortical thickness and surface area direct attention away from processes that selectively affect one cortical component toward mechanisms controlling the maturation of multiple cortical dimensions.
authors.affiliation: Child Psychiatry Branch, National Institute of Mental Health, Bethesda, Maryland 20892, USA. shawp@mail.nih.gov
authors.forename: Philip
authors.initials: P
authors.lastname: Shaw
authors.forename: Meaghan
authors.initials: M
authors.lastname: Malek
authors.forename: Bethany
authors.initials: B
authors.lastname: Watson
authors.forename: Wendy
authors.initials: W
authors.lastname: Sharp
authors.forename: Alan
authors.initials: A
authors.lastname: Evans
authors.forename: Deanna
authors.initials: D
authors.lastname: Greenstein
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology*; D002540:Cerebral Cortex / Q000254:growth & development* / Q000473:pathology*; D002648:Child; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006179:Gyrus Cinguli / Q000254:growth & development* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D015233:Models, Statistical; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales