By Steven Reinberg
FRIDAY, Feb. 17 (HealthDay News) -- In children as young as 6 months old, changes in the brain that can lead to autism spectrum disorder may have already begun, preliminary research suggests.
Although early signs of autism, such as problems communicating and repetitive behaviors, can often be seen as early as 1 year, processes in the brain linked to communication are seemingly being altered months earlier, University of North Carolina researchers report.
"We know that there is evidence that autism affects the ability of different brain regions to communicate with each other. This study confirms that this atypical brain development begins very early in life," said study co-author Geri Dawson, the chief science officer at Autism Speaks.
"These findings raise the possibility of developing imaging markers that could detect risk for autism in advance of actual symptoms, and [to] begin treatment before symptoms begin," she said.
However, whether these brain changes occur in all autistic children isn't known, Dawson said. It is possible that the developmental problems of autism start even earlier, while in the womb, she said.
"One can imagine a day when you would use these imaging biomarkers to identify a young baby who is at risk and then provide them with early stimulation that could, hopefully, reduce or even prevent the onset of autism," Dawson said.
The report was published in the Feb. 17 online edition of the American Journal of Psychiatry.
For the study, a team led by Jason Wolff, a postdoctoral fellow at the Carolina Institute for Developmental Disabilities at the University of North Carolina, used MRI brain scans to look for early brain development in 92 infants.
These babies all had older sisters or brothers who had been diagnosed with autism spectrum disorder, putting these infants a higher risk for developing the condition, the researchers noted.
The children underwent a special type of MRI called diffusion tensor imaging at 6 months, 1 year and 2 years of age. These repeated scans allowed the researchers to make three-dimensional pictures that show changes in "white matter." White matter is a part of the brain particularly embedded with nerve fibers that form information pathways between different areas of the brain.
Of the 28 infants who developed autism spectrum disorder, the scans showed different white matter development in 12 of the 15 brain pathways the researchers looked at, compared with 64 infants who did not go on to develop autism spectrum disorder.
At 6 months, these pathways were denser than usual in the babies who developed autism spectrum disorder, but on later scans development had slowed. At two years, the pathways were less dense than those of typical toddlers, the researchers found.
These differences suggest that white matter development is affected during early childhood, at the very time the brain is making and strengthening these vital connections, the investigators said.
"These brain changes appear to occur in advance of many symptoms," said Wolff. "Autism unfolds over early development, and this process may begin with basic differences in brain connections."
These early brain changes suggest the potential for biological signs for early detection of autism, Wolff said. "This is an initial study, but [it] holds promise for the development of early detection down the road," he added.
In addition, there is the potential for intervention that could disrupt the process that leads to autism, Wolff added. "We may be able to intervene before autism fully manifests," he said.
This study is part of a larger, ongoing multi-site study, Wolff said. "This is an initial sub-sample, and we are aiming to enroll about 400 infants at high risk for autism and 150 at low risk. Eventually we will be able to report on development of both brain and behavior in this group," he said.
Dr. Andrew Adesman, chief of developmental & behavioral pediatrics at the Steven & Alexandra Cohen Children's Medical Center of New York in New Hyde Park, said one drawback to this approach is the number and cost of MRIs that would have to be done to identify babies at risk for autism.