Declining eye contact in infants as young as 2 months old may be one of the earliest indicators of autism spectrum disorder (ASD), new research suggests.
A prospective study, which followed 110 children from birth to age 3 years, showed that those who had a subsequent diagnosis of ASD started life with relatively normal attention to others' eyes. However, their eye fixation began to decline between the ages of 2 and 6 months and continued declining to study's end. This pattern was not observed in typically developing children.
"This study is really exciting to us because it gives us a new glimpse on autism that we hadn't seen before," lead author Warren Jones, PhD, director of research at the Marcus Autism Center With Children's Healthcare of Atlanta, Georgia, and Emory University School of Medicine, told Medscape Medical News.
"It has helped us to identify the earliest signs of autism that we've ever observed. And it gives us some proof that it's possible to identify these signs within the first months of life," said Dr. Warren.
The study was published online November 6 in Nature.
Prior Hypothesis Contradicted
Although deficits in eye contact have been a hallmark of autism, information on the onset of these problems has not been investigated before.
"Unexpectedly, those early levels of eye looking seem to begin at normative levels," the researchers write. "This contradicts prior hypotheses of a congenital absence of social adaptive orientation and suggests instead that some social adaptive behaviors may initially be intact in newborns later diagnosed with ASD," they add.
Earlier this year, as reported by Medscape Medical News, researchers from Yale presented preliminary findings from a pilot study at a press briefing organized by the Brain and Behavior Research Foundation.
These results showed that brain activity, as recorded by electroencephalogram (EEG), after toddlers made eye contact was weaker for those with ASD compared with their normally developing counterparts.
In the current study, the investigators sought to explore the association between eye contact and ASD in a younger population.
"We were looking for precursor signs rather than the final manifestation of symptoms. For example, if we wait for the heart attack to happen, it's harder to make progress. Similarly, we were trying to look for mechanisms of typical social development and the way those mechanisms may not be developing in kids with autism," said Dr. Jones.
The researchers enrolled 110 infants and divided them into 2 groups. The high-risk group consisted of those who had an older full sibling diagnosed with ASD (n = 59), whereas the low-risk group did not have any first-, second-, or third-degree relatives with ASD (n = 51).
At 10 different time points, when the children were between the ages of 2 and 24 months, eye movements were tracked as the infants watched videos of a caregiver. Percentage of time that a child fixated on the video caregiver's eyes, mouth, body, and nonhuman spaces was then calculated.
Results showed that 12 of the children (20.3%, 10 of whom were boys) in the high-risk group met diagnostic criteria for ASD by age 3 years vs just 1 child (a boy) in the low-risk group.
The investigators than compared the 11 boys with ASD with 25 boys from the low-risk group without ASD.
After reviewing the eye-tracking data, the investigators found a steady decline in time spent looking at a caregiver's eyes in those with ASD. This decline began predominantly when the children were between age 2 and 6 months and continued to decline throughout the course of the study.
In contrast, when the typically developing children were between the ages of 2 and 6 months, they looked significantly more at the eyes than at any other area of the caregiver measured (P < .001).
At age 24 months, those with a later diagnosis of ASD focused on others' eyes half as long as children who did not develop ASD (P = .002).
This decline "was somewhat surprising," noted the researchers in a release. They added that a long-standing theory has been that social behaviors are completely missing in those with ASD. However, this study suggests that "social engagement skills are intact shortly after birth."
"This insight, the preservation of some early eye-looking, is important because in the future, if we were able to use similar technologies to identify early signs of social disability, we could then consider interventions to build on that early-looking and help reduce some of the associated disabilities that often accompany autism," added Dr. Jones.
He told Medscape Medical News, though, that parents and clinicians should not expect to see these differences in eye fixation by themselves.
"The signs we observed are only visible with the aid of sophisticated technology, and they required many measurements over many months," he explained.
"So the important take-away for parents is that if they have concerns, they should speak with their pediatricians and check out important links from the CDC [Centers for Disease Control and Prevention]."
Possibility of Earlier Intervention
"Autism isn't usually diagnosed until after age 2, when delays in a child's social behavior and language skills become apparent," Thomas R. Insel, MD, director of the National Institute of Mental Health (NIMH), said in a release.
However, he noted that this study showed that children "exhibit clear signs" of ASD at a much younger age than previously thought, which is a good thing for the field.
"The sooner we are able to identify early markers for autism, the more effective our treatment interventions can be," said Dr. Insel.
Dr. Jones added that his hope is that as he and his investigative team conduct more studies and enroll more families, in the event that these findings are replicated, they will lead to "real, viable tools for early detection in the future."
"More research is the next step. It showed us that it's possible to identify these signs. But now we want to understand what the extent of variability is on these signs in this population," he said.
The study was funded by grants from the NIMH and from the Simons Foundation. The study authors have disclosed no relevant financial relationships.
Nature. Published online November 6, 2013. Abstract
Medscape Medical News © 2013 WebMD, LLC
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Cite this: Earliest Sign of Autism: The Eyes May Have It - Medscape - Nov 14, 2013.