Eye contact declines in young infants with autism
Beginning as young as two months of age, infants later diagnosed with autism show a steady decline in eye contact that might be the earliest marker yet for the disorder. If confirmed, the finding might lead to earlier autism diagnosis and treatment.
Autism is a complex brain disorder that affects about 1 in 88 children. A main symptom is impaired social interaction, including a lack of eye contact. Autism symptoms first appear during early childhood, and a definitive diagnosis can often be made by two years of age. Scientists have long been searching for ways to identify the condition at even younger ages, since outcomes tend to be better with earlier intervention.
In hope of finding an autism marker that's present in the first months of life, Drs. Warren Jones and Ami Klin of Emory University School of Medicine studied eye movements in a group of 110 infants starting at 2 months of age. The infants were separated into 2 groups based on their risk for developing autism spectrum disorder. Those in the high-risk group had an older sibling already diagnosed with autism; those in the low-risk group did not. The research was funded in part by NIH's National Institute of Mental Health (NIMH). Results were reported online in Nature on Nov. 6.
Using eye-tracking equipment, the scientists measured the children's visual scanning as they watched videos of a caregiver. The researchers calculated the percentage of time each child fixated on the caregiver's eyes, mouth, body, or nonhuman regions of the images. Children were tested at 10 different times between 2 and 24 months of age.
By 3 years of age, 12 of the 59 children in the high-risk group (about 20 percent) and one child in the low-risk group had been diagnosed with an autism spectrum disorder. The researchers then reviewed the eye-tracking data to see what factors differed between those who had received an autism diagnosis and those who hadn't.
At two months of age, attention to eyes (eye-looking) was similar in children with and without an autism diagnosis. But between two and six months, eye-looking behavior began to drop in the children later diagnosed with autism. The decline continued throughout the course of the study. By 24 months, the children with autism focused on the caregiver's eyes only about half as long the children without autism.
The researchers were surprised to find that eye-looking behaviors appeared normal at 2 months of age, since a long-standing theory holds that social behaviors are entirely absent in children with autism. The finding suggests that some social engagement skills initially may be intact in newborns later diagnosed with autism.
"This insight, the preservation of some early eye-looking, is important," says Jones. "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 eye-looking and help reduce some of the associated disabilities that often accompany autism."
The scientists are now enrolling babies and their families into longer term studies in an effort to translate their findings into usable tools for the clinic.
--From the National Institute of Health
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