Article

A Prospective Study of the Emergence of Early Behavioral Signs of Autism

MIND Institute, University of California-Davis, Sacramento, California 95817, USA.
Journal of the American Academy of Child and Adolescent Psychiatry (Impact Factor: 6.35). 03/2010; 49(3):256-66.e1-2. DOI: 10.1097/00004583-201003000-00009
Source: PubMed

ABSTRACT To examine prospectively the emergence of behavioral signs of autism in the first years of life in infants at low and high risk for autism.
A prospective longitudinal design was used to compare 25 infants later diagnosed with an autism spectrum disorder (ASD) with 25 gender-matched low-risk children later determined to have typical development. Participants were evaluated at 6, 12, 18, 24, and 36 months of age. Frequencies of gaze to faces, social smiles, and directed vocalizations were coded from video and rated by examiners.
The frequency of gaze to faces, shared smiles, and vocalizations to others were highly comparable between groups at 6 months of age, but significantly declining trajectories over time were apparent in the group later diagnosed with ASD. Group differences were significant by 12 months of age on most variables. Although repeated evaluation documented loss of skills in most infants with ASD, most parents did not report a regression in their child's development.
These results suggest that behavioral signs of autism are not present at birth, as once suggested by Kanner, but emerge over time through a process of diminishment of key social communication behaviors. More children may present with a regressive course than previously thought, but parent report methods do not capture this phenomenon well. Implications for onset classification systems and clinical screening are also discussed.

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    • "Only a handful live eye-tracking studies have been published so far involving children with ASD (Falck-Ytter, Carlström, & Johansson, 2015; Hanley, et al., 2014; Nadig, Lee, Singh, Bosshart, & Ozonoff, 2010; Noris, Nadel, Barker, Hadjikhani, & Billard, 2012). One reason why so few studies of this type have been conducted may be that eye-tracking experiments involving live person-to-person interaction can be more methodologically challenging and time consuming than conventional (screenbased ) eye tracking (Gredebäck, Fikke, & Melinder, 2010; Risko, Laidlaw, Freeth, Foulsham, & Kingstone, 2012). "
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    • ". This group of infants are at heightened risk of developing ASD themselves , and so can be followed prospectively to identify early markers of later diagnosis . Several recent such studies have revealed that infants with later ASD show remarkably typical patterns of looking at social stimuli in early infancy ( e . g . , Elsabbagh et al . , 2013 ; Ozonoff et al . , 2010"
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    • "When measuring prospective control during reaching we are tapping into the microstructure of motor performance, a level of detail not assessed by established developmental tests. Previous longitudinal studies focusing on standardized test items (such as the MSEL), have identified group differences (Landa & Garrett-Mayer, 2006; Ozonoff et al., 2010) with consistently lower scores in the HR samples, but it is difficult to point to specific motor functions based only on such measures. Furthermore, in these studies, group differences have been proven difficult to show before twelve months of age (but see Leonard, Elsabbagh, Hill, & Basis Team, 2014; Libertus et al., 2014), and it might be that the infants in this sample are too young for such group differences to be detected. "
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