"This is a very preliminary step and one that will require larger samples of children and a broader range of children with autism and other development disorders, particularly other developmental language disorders," Mostofsky said.
Also unknown is how old a child has to be for the deviations in brain circuitry to show up on the MRI. At birth, the brain's gray and white matter is largely undifferentiated, although this changes rapidly during the first 18 to 24 months, Lange said.
The specific type of MRI used is called diffusion tensor imaging, which offers information about the structure of the brain as opposed to how the brain "lights up" during particular activities.
Among the specific findings in participants with autism, the fibers in the right side of the superior temporal gyrus were more organized than the fibers on the left; the opposite was true in typical people.
"The left is language. Typical brains have nice, coherent, organized fiber structures," Lange said. "In those with autism, the left is less organized."
Researchers repeated the MRI test with a second set of participants and had similar success in predicting who had autism and who didn't.
The U.S. National Institute of Neurological Disorders and Stroke has more on autism.
SOURCES: Nicholas Lange, Sc.D., associate professor, psychiatry, Harvard Medical School, and director, Neurostatistics Laboratory, McLean Hospital, Boston; Stewart Mostofsky, M.D., medical director, Center for Autism and Related Disorders, Kennedy Krieger Institute, Baltimore; Dec. 2, 2010, Autism Research,
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