Both studies used MRI (magnetic resonance imaging) scanning technology to analyze brain volume in those with autism, and age-matched control groups.
In the first study, which set out to explore anatomical differences in the brains of very young autistic children, the brain volume measurements of 45 autistic children, ages 3 and 4, were compared with those of 26 children with typical development and 14 children with developmental delay. "We found that the autistic children had significantly increased cerebral volumes compared to typically developing children and developmentally delayed children," according to study author Stephen R. Dager, MD, with the University of Washington School of Medicine in Seattle, WA. The average cerebral volume -- including measures of the cerebrum, cerebellum, amygdala, and hippocamus -- was 10 percent larger in autistic children than in typically developing children. The difference was 12.5 percent between autistic and developmentally delayed children. He said the study shows that abnormal brain development processes occur very early in autistic children.
Dager said more research is now underway to better ascertain the causes of the abnormalities as well as the disease's progression. The children in the study will undergo brain reimaging at age 6 to 7 years old, which will make it possible to track changes in behavioral symptoms and corresponding brain volume.
The study was supported by a grant from the National Institute of Child Health and Human Development and the National Institute on Deafnesss and Communication Disorders, and the Cure Autism Now Foundation (CAN).Using a separate sample, researchers at the same university hypothesized that brain growt
Contact: Cheryl Alementi
American Academy of Neurology