Feb. 17, 2012 -- Differences in brain development may be evident as early as age 6 months in children who go on to develop autism, according to new research.
In the study, children later diagnosed with autism spectrum disorder (ASD) had abnormal development of the white matter in the brain, says researcher Joe Piven, MD, director of the Carolina Institute for Developmental Disabilities at the University of North Carolina, Chapel Hill.
White matter is rich in nerve fibers. It is crucial so the regions of the brain can ''talk'' to each other. This study has found the earliest brain differences in autism, Piven believes.
"There is an aberrant pattern related to autism," he tells WebMD.
"As early as 6 months, the brain of a child who develops autism is organizing itself differently," says researcher Jason Wolff, PhD, a University of North Carolina postdoctoral fellow.
The study is published in the American Journal of Psychiatry.
Autism spectrum disorders are complex developmental brain disorders. ASDs now affect one in 110 U.S. children, according to the CDC. Genetic and environmental factors are blamed. People with the condition have social and behavioral challenges and repetitive behaviors.
Researchers are trying to find early clues of ASD, before symptoms develop.
Researchers have suspected that the brains of children with autism ''are just connected differently," Wolff says. Other studies have shown differences, he says. These other studies have focused mainly on older children.
Piven's team suspected that autism unfolds much earlier. They designed the new study to look closely beginning in infancy.
The researchers tracked 92 high-risk infants. All had an older sibling who had autism spectrum disorder. They began at age 6 months.
The researchers used a special magnetic resonance imaging (MRI) to evaluate the infants' brains at 6 months, 1 year, and 2 years. They produced three-dimensional images to show the changes over time in each child's white matter.
They looked at 15 white matter areas.
They did behavioral assessments at 24 months. They looked for symptoms of autism spectrum disorder. At 24 months, 28 children were diagnosed with ASD. The other 64 were not.