title: Reduced engagement with social stimuli in 6-month-old infants with later autism spectrum disorder: a longitudinal prospective study of infants at high familial risk.
abstract: BACKGROUND
  Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects more than 1 % of the population and close to 20 % of prospectively studied infants with an older sibling with ASD. Although significant progress has been made in characterizing the emergence of behavioral symptoms of ASD, far less is known about the underlying disruptions to early learning. Recent models suggest that core aspects of the causal path to ASD may only be apparent in early infancy. Here, we investigated social attention in 6- and 12-month-old infants who did and did not meet criteria for ASD at 24 months using both cognitive and electrophysiological methods. We hypothesized that a reduction in attention engagement to faces would be associated with later ASD.
  
  
  METHODS
  In a prospective longitudinal design, we used measures of both visual attention (habituation) and brain function (event-related potentials to faces and objects) at 6 and 12 months and investigated the relationship to ASD outcome at 24 months.
  
  
  RESULTS
  High-risk infants who met criteria for ASD at 24 months showed shorter epochs of visual attention, faster but less prolonged neural activation to faces, and delayed sensitization responses (increases in looking) to faces at 6 months; these differences were less apparent at 12 months. These findings are consistent with disrupted engagement of sustained attention to social stimuli.
  
  
  CONCLUSIONS
  These findings suggest that there may be fundamental early disruptions to attention engagement that may have cascading consequences for later social functioning.
authors.affiliation: Centre for Brain and Cognitive Development, Birkbeck College, University of London, London, UK.
authors.forename: E J H
authors.initials: EJ
authors.lastname: Jones
authors.affiliation: Center on Human Development and Disability, University of Washington, Seattle, WA USA.
authors.forename: K
authors.initials: K
authors.lastname: Venema
authors.affiliation: Center on Human Development and Disability, University of Washington, Seattle, WA USA.
authors.forename: R
authors.initials: R
authors.lastname: Earl
authors.affiliation: Center on Human Development and Disability, University of Washington, Seattle, WA USA ; Department of Speech and Hearing Sciences, University of Washington, Seattle, WA USA.
authors.forename: R
authors.initials: R
authors.lastname: Lowy
authors.affiliation: Center for Child Health, Behavior and Development, Seattle Children's Hospital, Seattle, WA USA.
authors.forename: K
authors.initials: K
authors.lastname: Barnes
authors.affiliation: Center on Human Development and Disability, University of Washington, Seattle, WA USA ; Department of Speech and Hearing Sciences, University of Washington, Seattle, WA USA.
authors.forename: A
authors.initials: A
authors.lastname: Estes
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC USA.
authors.forename: G
authors.initials: G
authors.lastname: Dawson
authors.affiliation: Center on Human Development and Disability, University of Washington, Seattle, WA USA ; Center for Child Health, Behavior and Development, Seattle Children's Hospital, Seattle, WA USA ; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Webb
keywords: ASD; Event-related potential; Habituation; Social attention; Social information processing