(RxWiki News) Despite the fact that autism affects one in 110 American children, little is known about the disorder and why it causes developmental delays from moderate to very severe.
New research shows one possible explanation: the regions of the brain that are important for language and social skills grow much more slowly in autistic boys than in non-autistic children.
"Autistic boys experience slower brain growth."
Researchers at the University of California Los Angeles discovered this abnormal brain growth pattern and believe it might be associated with the communication deficits, repetitive behaviors and social impairment that characterize autism.
Jennifer G. Levitt, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, and Xua Hua, a UCLA postdoctoral researcher conducted MRI brain scans on 13 boys diagnosed with autism and seven non-autistic boys, all ranging in age from age six to fourteen. Two scans were taken for each boy, approximately three years apart.
Through the scans, the researchers were able to create a detailed picture of brain growth and changes during development. Normally, as children grow the brain undergoes dynamic creation of white matter and the pruning of unused gray matter; but the brains of children with autism develop differently.
In the brain scans of the autistic boys, it was clear that the white-matter connections in the brain regions important for language and social skills were growing much more slowly.
In addition, the unused gray matter cells were not being properly pruned away in two areas of the brain involved in learning and cognitive and emotional processing.
Hua said that this growth pattern results in unusual brain circuits for autistic children, making it difficult for the brain to process information in a normal way. "The brain regions where growth rates were found to be the most altered were associated with the problems autistic children most often struggle with — social impairment, communication deficits and repetitive behavior," she added.
Levitt said that the study demonstrated that brain imaging could be used to determine the success of treatments on children with autism, and could result in different approaches. The findings were published in the October 2011 online edition of the journal Human Brain Mapping.