Autistic children don't find pleasure in hearing human voicesNEW YORK — Children with autism spectrum disorder may not perceive human voices as pleasurable because of a physical disconnect between the brain regions involved in speaking and those linked to rewards, a study suggests.
By: Bloomberg News, INFORUM
NEW YORK — Children with autism spectrum disorder may not perceive human voices as pleasurable because of a physical disconnect between the brain regions involved in speaking and those linked to rewards, a study suggests.
Brain imaging determined that the connections between the two brain regions were stronger in children who don't have the disorder than in those diagnosed with it, said Daniel Abrams, the lead author. That's important because communication problems are important diagnostic criteria for autism.
One in 50 U.S. children have been diagnosed with autism or a related disorder, such as Asperger's syndrome, according to the Centers for Disease Control and Prevention. The majority have difficulty using language effectively, including being unable to grasp nuances of speech such as rhythm and tone, according to the National Institutes of Health. The newest research, published in the Proceedings of the National Academy of Sciences, is the first to suggest why, Abrams said.
"There isn't a lot of data to strongly point at what are the root causes of the social deficits in children with autism," Abrams, a postdoctoral research fellow at Stanford University in California, said in a telephone interview. "We think it has this important motivation and reward component to it."
Autism and related disorders increased 72 percent among American school children in 2011 and 2012 from the previous five years, the CDC said in a report on March 20. About 2 percent of children ages 6 to 17 were diagnosed on the autism spectrum, compared with 1.16 percent of kids in the CDC's 2007 report.
Insensitivity to human speech can affect a child's early development, the authors said. Typical infants will listen to human speech and engage with sounds as a way to develop early language skills and emotional understanding, as well as to bond with their parents, the authors wrote.
Autistic children need to be motivated and encouraged to engage with speech and help it become a more rewarding sound, he said. Such efforts may be beneficial in helping overcome some of the wiring deficits in the brain.
"Some of the very first observations" for children with autism "are often that these kids are unresponsive to human speech," Abrams said.
Researchers in the study included 20 children with autism who were considered high functioning, with language skills and issues with communication. Their magnetic resonance imaging scans were compared with 19 children without the disorder who had similar intelligence.
The researchers looked at how the speech part of the brain was connected to other regions. Those with autism had weaker connections between the temporal lobe, where speech is controlled, and the dopamine reward pathway that elicits pleasurable feelings, the study found.
The research also found weak links between voice regions and parts of the brain that process emotional information, Abrams said. In the future, the researchers plan to look at whether there are certain parts or types of speech that activate an autistic child's brain, he said.
"People are really working hard on this and making some cool findings," Abrams said.
Mental health professionals this year revised the standards for diagnosing autism in their guidelines, the Diagnostic and Statistical Manual of Mental Disorders. Among the changes was a decision to collapse several conditions, including Asperger's syndrome and child disintegrative disorder, into a single autism diagnosis.