title: Distinct patterns of cortical thinning in concurrent motor and attention disorders.
abstract: OBJECTIVE
  Many neurodevelopmental disorders co-occur yet are rarely studied in terms of brain development. Developmental coordination disorder (DCD) and attention-deficit-hyperactivity disorder (ADHD) co-occur at a high frequency and are associated with functional and structural brain alterations. The objective of this study was to examine whether the effects of comorbid motor and attention problems influence cortical thickness in children and whether the pattern of changes for concurrent disorders is distinct from the alterations seen in single disorders.
  
  
  METHODS
  A total of 34 children (19 males, 15 females, mean age 9y 9mo, range 8-17y) who met the criteria for DCD (n=14), ADHD (n=10), or DCD+ADHD (n=10) were recruited into the study. Fourteen participants with typical development (eight males, six females, mean age 11y 9mo, range 8-17y) were also recruited for comparison. Participants underwent neuropsychological assessment and magnetic resonance imaging. Cortical thickness analysis was performed to determine the patterns of cortical thinning in each disorder, which was then compared across groups.
  
  
  RESULTS
  Children with comorbid DCD+ADHD demonstrated more widespread decreases in cortical thickness than participants with a diagnosis of DCD or ADHD alone. Cortical thinning was found to be concentrated in the frontal, parietal, and temporal lobes, and was correlated with measures of motor and attentional functioning.
  
  
  CONCLUSIONS
  The co-occurrence of DCD+ADHD was associated with a distinct global pattern of regional cortical thickness decrease, highlighting the unique neurobiology of comorbid neurodevelopmental disorders. This novel feature of concurrent DCD and ADHD may help inform diagnostic definitions and provide clues to both the shared and the isolated genetic and environmental origins of motor and attention disorders.
authors.affiliation: Department of Pediatrics, Behavioural Research Unit, Alberta Children's Hospital, University of Calgary, Calgary, AB, Canada; Department of Psychiatry, Alberta Children's Hospital, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, Alberta Children's Hospital, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute for Child and Maternal Health, Alberta Children's Hospital, Calgary, AB, Canada; Behavioural Research Unit, Alberta Children's Hospital, Calgary, AB, Canada.
authors.forename: Lisa Marie
authors.initials: LM
authors.lastname: Langevin
authors.forename: Frank P
authors.initials: FP
authors.lastname: MacMaster
authors.forename: Deborah
authors.initials: D
authors.lastname: Dewey
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology; D002540:Cerebral Cortex / Q000473:pathology* / Q000503:physiopathology; D002648:Child; D015897:Comorbidity; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D019957:Motor Skills Disorders / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology