MONDAY, July 22, 2002 (HealthDayNews) -- The brains of children with autism develop abnormally during the very early years of life, two new studies find.
Both studies, published in the current issue of Neurology, used magnetic resonance imaging (MRI) technology to analyze brain volume in those with autism, comparing them with control groups of children the same age.
In the first study, the brain volume measurements of 45 autistic children ages 3 and 4 were compared with those of 26 children with typical brain development.
The brains of the autistic children were found to be an average of 10 percent larger, according to study author Dr. Stephen Dager, with the University of Washington School of Medicine in Seattle. He said the study shows that abnormal brain development occurs very early in autistic children.
Dager said more research is underway to determine what causes the abnormalities.
In the second study, researchers at the same university found that brain growth among autistic patients is rapid in the early years of life, but that brain size begins decreasing around age 12. The study showed that by adulthood, an autistic person's brain volume levels out to normal size.
The second study measured brain volume and head circumference of 67 autistic children and adults and 83 healthy people ranging in age from 8 to 46. Among those with autism age 12 and under, average brain volume was 5 percent larger than among the control group. By age 12, there was no difference in volume, but head circumference was 1 percent to 2 percent greater in autistic people, whether children or adults.
The researchers in the second study acknowledged that the lack of participants under age 8 was a problem because they were unable to determine when the brain enlargement began.
More Information
For more details on autism, visit the National Institutes of Mental Health.
