The cause of autism has been linked to chemicals in air pollution in the past, but new research also suggests an autistic child's language difficulties are due to a disconnect in brain wiring.
"Researchers from Harvard University's School of Public Health found that pregnant women exposed to high levels of diesel particulates or mercury were twice as likely to have an autistic child compared with peers in low-pollution areas," Bloomberg News reported.
Children with autism are sometimes indifferent to people in social settings, and have communication difficulties. The first of its kind, a separate study published in Proceedings of the National Academy of Sciences suggests that weak connections in specific parts of an autistic child's brain relating to speaking are to blame.
"There isn't a lot of data to strongly point at what are the root causes of the social deficits in children with autism," Daniel Abrams, a postdoctoral research fellow at Stanford University in California, told Bloomberg News. "We think it has this important motivation and reward component to it."
The study included 20 high-functioning autistic children with language skills and issues with communication, as well as 19 children without the disorder who "had similar intelligence."
Brain imaging scans were used in the language study to map out the connections in an autistic child's brain. The researchers studied the speech part of the brain and how it was connected to neighboring regions.
"Those with autism had weaker connections between the temporal lobe, where speech is controlled, and the dopamine reward pathway that elicits pleasurable feelings," Bloomberg News reported.
Researchers also found weak links in voice regions and parts of the brain that process emotional information. Insensitivity to human speech reportedly can affect a child's early development, as infants normally listen to human speech and engage with sounds to develop early language skills.
Though the cause of autism still unknown, some researchers reportedly believe all factors, including genetics, are important to the study of the disorder.
