Nicole Anthony understands the challenges of raising a child with autism. Her 13-year-old son, Miyka-El, has a milder form of the condition.
She said one of his biggest problems is responding to other people in social situations.
"Children with autism miss out on those social cues that other children will pick up on and pay attention to," she said.
Miyka-El has doesn't even do seemingly mundane things, like yawn in response to someone else yawning, which is something most people do unconsciously.
"Something like that won't affect him. He's in his own world, and if you're doing what he's not interested in doing, he's not going to pay attention," she said.
According to a small new study, Miyka-El Anthony isn't alone. A group of researchers found that children with autism were about half as likely as non-autistic children to mimic someone yawning.
The study, published in the latest issue of the journal Child Development, also found that children with a milder form of autism yawned in response to someone else yawning more often than children with more severe autism. Researchers also discovered that responding to contagious yawning happens significantly more often starting at age four.
Experts say these results add another piece of understanding to the autism puzzle. While they're unsure about whether these findings have any practical application, they agree that learning about autistic children's inability to respond to something as simple as a yawn says a lot about what the disorder really is.
"It's a great example of exactly how pervasive the challenges are that individuals on the autism spectrum have to face," said Susan Wilczynski, executive director of the National Autism Center in Randolph, Mass. "This deficit in social awareness is so severe that it affects something as minute and neurologically based as contagious yawning."
Lead researcher Molly Helt, a doctoral candidate at the University of Connecticut, Storrs, decided to focus on contagious yawning after discovering that her own autistic son didn't mimic her when she was trying to get him to yawn to unclog his ears while on a plane.
She said the results are consistent with a common belief about children with autism.
"Kids well beyond the age of four or five seem not to be becoming emotionally attuned, missing some cues that bind us all together," said Helt.
"We know that it's a general rule that humans are wired to recognize emotion and respond to it, and children with autism tend not to feel it as much or feel it in a different way," said Dr. Jeffrey Brosco, professor of clinical pediatrics at the University of Miami School of Medicine.
Other autism experts agree, and add that understanding the response to certain cues, such as yawning, is vital to understanding what's behind the key facets of autism.
"[A]lthough yawning in and of itself may not signal any particular strong emotion, the tendency to yawn when others do appears to be part of a larger ability to respond emotionally in a similar way to those around us," said Lori Warner, director of the HOPE [Hands-On Parent Education] Center at Beaumont Hospital in Berkley, Mich.
"Early differences in attending to and responding to [nonverbal] behaviors may be related to the development of core symptoms of autism," said Laura Silverman of the University of Rochester Medical Center's Department of Pediatrics in Rochester, N.Y.