Findings of a new study that used a special technology to monitor the eye movement of children with autism spectrum disorder (ASD) during conversation have revealed a way to spot those who have the developmental disability.
For the study, which was published in the June issue of Research in Autism Spectrum Disorders, researchers used eye tracker technology to monitor the eye movements of children between 6 and 13 years old who were diagnosed with autism and 19 children who do not have the development disorder.
Study author Tiffany Hutchins, from the University of Vermont, and colleagues found that those with autism were more likely to focus on the speaker's mouth instead of the eyes once the conversation shifted to emotional topics such as what makes the children afraid or sad.
The researchers likewise observed that children with more severe autism and poorer intellectual and verbal abilities tend to focus more on the speaker's mouth than the eyes during emotional conversation.
The same behavior was observed in those with more limited executive function, which help people pay attention, get things done and manage time.
"Compared to the typically developing (TD) children group, the ASD group had significantly fewer fixations to eyes and increased fixation time to mouths during a conversation about 'how people feel' but not about 'what people do'," the researchers wrote in their study.
While it isn't clear why children with autism appear to be more fixated on the mouth during emotional talks, the researchers theorize this could be because the conversation strains the children's executive function.
Hutchins explained that highly emotional topics may demand more on working memory and the rendering of information from the eye regions becomes difficult once a threshold is surpassed. This may explain why children with autism may begin to search elsewhere for more accessible information.
Hutchins said that for children with ASD, emotional conversations are comparable to driving in a snowstorm.
"In that situation, you are totally focused, every move is tense and effortful, and your executive function drains away," Hutchins said. "Decreased working memory correlated with decreased eye fixations, so as working memory decreases, then we see fewer fixations on the eyes."
The findings of the research could potentially affect how speech therapists treat children who struggle with the social, behavioral and communication challenges faced by children with ASD.
It is estimated that one in every 68 children suffers from the developmental disability. While no cure is currently available for ASD, research suggests early intervention treatment may help improve the development of children with the condition.