MONDAY, Dec. 12, 2011 (HealthDay News) -- Toddlers with autism show different blink patterns than other children, a finding that researchers say may provide a clue to the way people with autism process what they see.
Blinking is largely an involuntary process that helps keep the eyes hydrated and protected. During that split second that your eyes are closed, you are temporarily blinded. And throughout a typical day, adults spend about 44 minutes with their eyes closed.
The current study got started when Sarah Shultz, a graduate student at the Yale Child Study Center, noticed that kids blink less often when watching videos. She and her colleagues wondered: Would kids with autism, who have impairments in social communications, including reading facial expressions and interacting with others, show the same blink timing?
In the study, researchers had 93 typically developing children and children with an autism spectrum disorder, all aged 2, watch short videos of two children in a wagon who get into an argument over whether the wagon door should be open or shut. Using eye-tracking technology, the researchers tracked when and how often the kids blinked.
Researchers found that both the kids with autism and typically developing kids blinked less during the video.
However, typical kids blinked less during the emotional exchange between the kids, while the autistic kids blinked less when there were moving parts, such as the wagon door being slammed.
"We have a new way of understanding not just what people are looking at but how engaged they are with what they're looking at," said senior study author Warren Jones, director of research at the Marcus Autism Center and an assistant professor in the department of pediatrics at Emory University School of Medicine in Atlanta.
"The more engaged you are, the less likely you are to blink," Jones said. "That's what we saw with those 2-year-olds. We were stunned to see typically developing 2-year-old kids would not blink when something emotionally exciting or charged was happening in the movie. What we saw in 2-year-olds with autism was they were more likely not to blink while looking at physical objects in motion."
When you blink, you "lose" a bit of information, Jones added. Therefore, not blinking is a sign that kids find that information most important, engaging or relevant.
The study is published in this week's online issue of the Proceedings of the National Academy of Sciences.
Prior research has found that kids with autism pay less attention to social cues and social information, Jones said. "What these new findings and new measure really gives us is an opportunity to look at in more detail how kids with autism are engaging in whatever it is they are looking at," he said.
Rebecca Landa, director of the Center for Autism & Related Disorders at Kennedy Krieger Institute in Baltimore, said the study uses a "novel" technique to examine how kids with autism process information and respond to things they see.
"The more evidence that we have about the nature of the information that children with autism are either delayed in deciphering -- in this case, through visual pathways -- or that they have certain preferences or biases for, the more informed we can be in the development of interventions," Landa said. "That's why this is important. We try to take ever more precise steps into understanding what children with autism understand and how they extract information from the world around them."
The study also found that typically developing kids "inhibited" their blinking sooner than the kids with autism, suggesting that they're better able to anticipate what might unfold between the two children on screen.
"There's a growing body of information that young children with autism are not paying attention to or extracting information from social sequences in the same way as typical kids," Landa said, noting that treatments that break down such information into smaller bits, as well as making sure kids with autism are repeatedly exposed to such situations, may help them start to comprehend the emotional aspects of social interactions.
Geraldine Dawson, chief science officer for Autism Speaks, said it's well-established that unlike typical kids, young children with autism pay more attention to objects than people. "However, this is the first study to my knowledge that has used blinking to assess how engaged a child is with what he or she is viewing," Dawson said.
The results suggest that blinking could be used as a way of measuring whether therapies designed to help a child with autism increase their emotional engagement are working, she said.
"If a child is not visually engaged with the social world, this can affect the development of neural systems that underlie social behavior which rely on social stimulation for development," she added. "The hope is that, as a result of therapy, the young child with autism will show higher levels of attention and engagement with the social world and this will open up opportunities for learning."
The U.S. National Institute of Mental Health has more on autism.