While the number of children studied was small — and the researchers are now studying more children — experts not involved in the study said the results were significant because of the careful and repeated measurements that were not just snapshots, but showed change over time.
“It’s well done and very important,” said Dr. Geraldine Dawson, director of the Center for Autism Diagnosis and Treatment at Duke University. She said it was notable that “early on these babies look quite normal; this really gives us a clue to brain development.”
She said a possible explanation was that, early in life, activities like looking at faces are essentially reflexes “controlled by lower cortical regions of the brain that are likely intact” in children with autism. But “as the brain develops, babies begin to use these behaviors in a more intentional way. They can look at what they want to look at. We think that these higher cortical regions are the ones that are not working the same” as in typical children.
Dr. John N. Constantino, a child psychiatrist and pediatrician at Washington University in St. Louis, said the study showed that “babies who develop autism are for the most part doing an awful lot of things right for the first few months.” Perhaps the genes that drive autism begin to derail typical development after that, so that “what you are looking at moment by moment, day by day, second by second, is completely different from what other children are looking at, and the cumulative experience is what sends you off into the trajectory of autism.”
The researchers found that children who developed autism paid somewhat more attention to mouths and sustained attention to bodies past the age when typical children became less interested. Even more noticeable was that children who developed autism looked more at objects after the first year, while typical children’s interest in objects declined.
“We’re measuring what babies see, but more importantly we’re measuring what they don’t see,” Jones said.
Dawson said that looking at people teaches babies about “facial expressions and language and gesture. If the baby who’s developing autism is paying attention to objects, they’re really losing out on those opportunities.”
Before this study, experts said, research found that potential signs of autism — including differences in temperament, eye contact and pointing out objects — could be detected late in a child’s first year. Most cases of autism in children are diagnosed between ages 3 and 5, although the American Academy of Pediatrics recommends screening children at between 18 and 24 months.
But the new study suggests the need to develop therapies that begin even earlier. “The train has long left the station if you don’t start intervention until 18 months,” Constantino said.
Jones said eye contact was “just one very important channel.”
He continued, “I think we’d see the same things if we were measuring a child’s social reciprocity via touch or auditory listening preferences, but those are harder to measure.”
He and Klin advocate the eventual use of eye tracking and other measures in social development growth charts, similar to height and weight charts. Still, the authors and other experts cautioned that the results required confirmation in many more children.
Autism is so complex and varied that eye-tracking is unlikely to be able to identify every condition on the autism spectrum, Zwaigenbaum and others said. But they said the study helped illustrate the need for therapies to increase social engagement among very young infants, “either by intensifying the experience for them or making it pleasurable in other ways,” Constantino said.
“It really does present an opportunity for seeing if we could do some preventative interventions,” said Dr. Sally Ozonoff, vice chairwoman for research in psychiatry and behavioral sciences at the MIND Institute of the University of California, Davis. “Maybe you could keep the child from heading into that decline, so it doesn’t turn into autism.”