Yes, there are gender differences in cognitive function, but they're more limited than previously thought. And yes, income does affect cognitive performance but less than expected when only healthy children are considered. And while basic cognitive skills steadily improve in middle childhood, they then seem to level off questioning the idea of a burst of brain development in adolescence. These findings, published online on May 18 in the Journal of the International Neuropsychological Society, are the first data to emerge from the National Institutes of Health (NIH) MRI Study of Normal Brain Development, a large, population-based study that began in 1999 and is documenting structural brain development and behavior from birth to young adulthood.
The analysis, led by Deborah P. Waber, PhD in the Department of Psychiatry at Children's Hospital Boston, focused on cognition and behavior in healthy 6- to 18-year-olds enrolled at Children's and five other metropolitan areas across the United States. Population-based sampling techniques used U.S. Census data to ensure demographic diversity. A rigorous screening process eliminated children with medical, neurologic or psychiatric disorders, familial risk factors for such disorders, or prenatal exposure to toxic substances, providing a glimpse of how a healthy brain develops.
"This report and many others that will follow provides a comprehensive set of benchmark values that clinicians and scientists studying brain development can reference for many years to come," said NIH Director Elias A. Zerhouni, MD.
From an initial sample of more than 35,000 target families, the researchers were able to enroll approximately 450 children, of whom 385 were 6 years or older. Once enrolled, the children underwent MRI scans of the brain and completed a battery of behavioral and cognitive tests to ascertain their overall IQ, verbal ability, mental processing speed, spatial ability, memory, fine motor dexteri
Contact: Alissa Rooney
Children's Hospital Boston