Infants lose tendency to gaze at others’ eyes during first half-year
A sign of autism may appear in babies just a few months old. Between 2 and 6 months after birth, infants who will later develop an autism spectrum disorder lose interest in looking at other people’s eyes, scientists report November 6 in Nature.
The results will have “huge implications” for spotting the disorder early, says cognitive neuroscientist Atsushi Senju of Birkbeck, University of London, who was not involved with the study. Many children with autism aren’t diagnosed until age 4 or older. With reliable early indicators of the disorder, therapies could start much sooner and potentially ease or prevent future deficits.
The research could also give clues about what goes wrong in autism as the brain grows in the months after birth, Senju says.
Warren Jones and Ami Klin, of the Marcus Autism Center in Atlanta, studied babies with an older sibling diagnosed with an autism spectrum disorder, who are known to have 20 times the risk of developing autism. The researchers compared them with babies who have no immediate relatives with autism. Of the infants Jones and Klin studied, 11 boys went on to be diagnosed with autism at age 3.
Initially, the researchers found no differences between the babies who later developed autism and the babies who have no relatives with autism. At 2 months of age, all of the babies spent more time looking at the eyes of a woman in a video than at her mouth, body or nearby objects. But in the months that followed, this behavior dwindled in the children who later developed autism.
Brain development has probably begun to go awry by the time this behavioral deficit shows up, Jones says. But the presence of a normal eye gaze at 2 months might offer hope for very early treatments, he says.
Most people with autism do not have a sibling with the disorder. Because the study followed infants with siblings with autism, the results might apply only to them, Senju cautions.
The experiment used sophisticated eye-tracking equipment to uncover the change in behavior, something that can’t be seen by causal observation. “We don’t want to set off anxiety in parents,” Jones says. “The findings in this study are not things that parents, or even [medical] professionals, are going to be able to observe by eye.”
W. Jones and A. Klin. Attention to eyes is present but in decline in 2-6-month-old infants later diagnosed with autism. Nature. Published online November 6, 2013. doi:10.1038/nature12715.
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