An early sign of autism—declining eye contact—may be detected in infants as young as just a few months old, according to a new study. The findings, published online today in the journal Nature, may open a new avenue into developing early interventions for autism spectrum disorders (ASD).
Experts have known for decades that children with ASD don’t make eye contact with people as well as children who don’t have the condition. But they weren’t certain whether children with ASD were born without that ability or if it diminished as they got older. If the latter were true, investigators wanted to find out when the decline begins.
To answer those questions, researchers at the Marcus Autism Center in Atlanta, an affiliate of the Emory University School of Medicine, studied 110 infants. About half of the infants were at high risk of developing ASD because they had an older sibling with the condition. The other half were at low risk, having no first-, second-, or third-degree relatives with ASD. By age 3 years, about 20% in the high-risk group and 1 boy in the low-risk group developed ASD.
During testing sessions, the infants watched videos of typical interactions that someone caring for a baby would display: talking and making facial expressions and hand gestures. The investigators used eye-tracking equipment to measure the infants’ visual scanning. They collected data 10 times, when the infants were aged 2 months to 2 years.
In the infants who eventually were diagnosed with ASD, the ability to make eye contact began to decline when they were 2 months old. By the age of 2 years, their ability to make eye contact was about half that of children who didn’t develop ASD. A steeper decline was linked with more severe disability. In typically developing children, eye contact increases over time.
“First, these results reveal that there are measurable and identifiable differences present already before 6 months,” co-investigator Ami Klin, PhD, director of the Marcus Autism Center, said in a statement. “And second, we observed declining eye fixation over time, rather than an outright absence. Both these factors have the potential to dramatically shift the possibilities for future strategies of early intervention.
“Our next step will be to expand these studies with more children, and to combine our eye-tracking measures with measures of gene expression and brain growth,” Klin added.