"Children with autism lack a social component to their play and don't 'adjust' their play accordingly when another is involved," said study co-author Blythe Corbett, an associate professor of psychiatry at Vanderbilt University in Nashville.
"For example, they tend to interact less with other children and show a preference to play alone or nearby with objects even when other children are near," she said.
Autism is a developmental disorder in which children have trouble communicating with others and exhibit repetitive or obsessive behaviors. About one in 68 children in the United States has been diagnosed with autism spectrum disorder, according to the U.S. Centers for Disease Control and Prevention.
In the new study, researchers conducted a series of experiments with 42 children, aged 8 to 12, who either had an autism spectrum disorder or were typically developing. The investigators collected samples of cortisol, a stress hormone, from the children's saliva before and after playing on the playground with another child.
"The arousal level of the children with autism during play suggests that interaction with peers can be quite stressful," Corbett said. "In this study, we also found a relationship between brain activity during play, behavior and stress level."
All of the children underwent brain scans while playing a computer game in which they believed they were playing a real person half the time and a computer the other half.
"Typical children showed vast differences based on play with human versus computer partners," Corbett said. "While we know that children with autism have difficulty with social play, the current study showed that the brain patterns of children with autism spectrum disorders activate similar brain regions regardless of whether they are playing with a child they met or playing with a computer partner."
One expert said the study, published recently in the journal Social Cognitive and Affective Neuroscience, had limitations.
"This study is attempting to provide some level of physiological measure to assess how children with autism spectrum disorders respond differently from neurotypical children during play," said Dr. Glen Elliott, chief psychiatrist and medical director of Children's Health Council in Palo Alto, Calif.
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