Although early intervention is a strong positive predictor of long-term outcome in Autism Spectrum Disorder (ASD), the condition is rarely diagnosed before 2 years.
Objectives:
To measure social visual engagement using eye-tracking methods in a longitudinal cohort of infants at risk for autism with the goal to assess their diagnostic value in the first year of life.
Methods:
In a longitudinal, prospective design, we used risk-based cohorts to ascertain case-control samples of infants with ASD and typically-developing controls, charting developmental course of visual attention to other people from 2 until 24 months of age. Experimental measures were densely sampled, with 10 data collection sessions per child, 5 of which occurred between months 2 and 6.
Results:
From at least 2 months of age, infants with ASD follow a significantly different developmental trajectory in their visual attention to other people, with decline in fixation on others’ eyes and increased fixation on body and object areas. Longitudinal change in fixation to eye and mouth regions is highly correlated with severity of clinical outcome at 24 months: r = -.83, p=.002 and r = .88, p<.001, respectively. In addition, based only on data collected in the first 6 months of life, rate of change in eye fixation predicts diagnostic outcome with 78% se and 67% sp, while change in body fixation predicts outcome with 89% se and 79% sp.
Conclusions:
In a cohort of children tested repeatedly and intensively from month 2 until month 24, we have identified diagnostic markers during the first 6 months of life that differentiate infants with ASD from controls. This represents a crucial first step in advancing the earliest identification of ASD, a key factor in promoting optimal long-term outcome.
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See more of: Symptoms, Diagnosis & Phenotype