Researchers have found significant differences in brain development in infants as young as six months old who later develop autism, compared with babies who don't develop the disorder.
The study, by scientists at Washington University School of Medicine in St. Louis, the University of North Carolina at Chapel Hill and other centers, involved infants considered to be at high risk for autism because they had an older sibling with the diagnosis. The findings are published online in the American Journal of Psychiatry.
The new research, which relied on brain scans acquired at night while infants were naturally sleeping, suggests that autism doesn't appear abruptly, but instead develops over time during infancy.
"We were surprised that there were so many differences so early in infancy," says co-author Kelly N. Botteron, MD, who is leading the effort at the Washington University study site. "As this study moves forward, we may want to scan babies at even younger ages so that we can try to see how early this pattern is emerging."
The new findings involved brain scans from 92 infants who had completed diffusion tensor imaging (DTI), a type of MRI scan,at 6 months and behavioral assessments at 24 months of age. Most also had additional scans at 12 months or 24 months or both.
By 24 months, 28 of the infants (30 percent) met the diagnostic criteria for autism spectrum disorders. Scans of the infants with autism revealed changes in the pathways that connect brain regions to one another. In particular, the researchers found changes in multiple fiber pathways in the brain's white matter.
"The idea that connections may be less organized in children with autism fits with our hypothesis," says Botteron, a Washington University child psychiatrist at St. Louis Children's Hospital. "These children may have some changes in the brain's gray matter, too, but the way their neurons speak to each other clearly seems to be di
|Contact: Jim Dryden|
Washington University School of Medicine