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
BackgroundAutism 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.MethodsIn 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.ResultsHigh 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.ConclusionsThese findings suggest that there may be fundamental early disruptions to attention engagement that may have cascading consequences for later social functioning.
Journal of Neurodevelopmental Disorders