title: Prefrontal and occipital asymmetry and volume in boys with autism spectrum disorder.
abstract: OBJECTIVE
  To examine prefrontal and occipital asymmetry (brain torque) in boys with autism spectrum disorder (ASD) and controls. A secondary aim was to study age-related changes in gray and white matter volume.
  
  
  BACKGROUND
  Several studies have found atypical early cortical development in ASD. Atypical brain torque, defined as a greater-than-normal left prefrontal and right occipital asymmetry, has been found in some studies of children and adults with ASD. This configuration may be an early neural marker of ASD risk.
  
  
  METHODS
  We studied 24 right-handed boys with ASD and 27 typically developing right-handed boys, 7 to 15 years old, obtaining neuropsychological profiles and measuring prefrontal and occipital volumes on magnetic resonance images.
  
  
  RESULTS
  Most participants had the expected rightward prefrontal and leftward occipital asymmetry, with no group differences in direction or degree of asymmetry. We found a trend toward larger prefrontal volume in the ASD group than in the controls. The controls also had a trend toward differences in age associations, correlating with total and left prefrontal white matter volumes.
  
  
  CONCLUSIONS
  Our findings suggest that atypical brain torque may not be a neural signature of ASD, although our sample was limited to high-functioning, right-handed boys. Our results provide support for aberrant cortical development in ASD, continuing into adolescence, with prefrontal regions being disproportionally affected.
authors.affiliation: Brain and Behavior Program at Children's Hospital, New Orleans, LA 70118, USA.
authors.forename: Tracey A
authors.initials: TA
authors.lastname: Knaus
authors.forename: Helen
authors.initials: H
authors.lastname: Tager-Flusberg
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Mock
authors.forename: Rachel
authors.initials: R
authors.lastname: Dauterive
authors.forename: Anne L
authors.initials: AL
authors.lastname: Foundas
mesh_terms: D000293:Adolescent; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000473:pathology*; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009484:Neuropsychology; D009778:Occipital Lobe / Q000473:pathology*; D009929:Organ Size; D017397:Prefrontal Cortex / Q000473:pathology*