Autism affects the functioning of virtually the entire brain

A recent study provides evidence that autism affects the functioning of virtually the entire brain, and is not limited to the brain areas involved with social interactions, communication behaviors, and reasoning abilities, as had been previously thought.

The study, conducted by scientists in a research network supported by the National Institutes of Health (NIH), found that autism also affects a broad array of skills and abilities, including those involved with sensory perception, movement, and memory.

The findings, appearing in the August Child Neuropsychology, strongly suggest that autism is a disorder in which the various parts of the brain have difficulty working together to accomplish complex tasks.

The study was conducted by researchers in the Collaborative Program of Excellence in Autism (CPEA), a research network funded by two components of the NIH, the National Institute of Child Health and Human Development and the National Institute on Deafness and Other Communication Disorders.

"These findings suggest that further understanding of autism will likely come not from the study of factors affecting one brain area or system, but from studying factors affecting many systems," said the director of NICHD, Duane Alexander, M.D.

People with autism tend to display 3 characteristic behaviors, which are the basis of the diagnosis of autism, explained the study's senior author, Nancy Minshew, M.D., Professor of Psychiatry and Neurology at the University of Pittsburgh School of Medicine. These behaviors involve difficulty interacting socially, problems with verbal and non-verbal communications, and repetitive behaviors or narrow, obsessive interests. Traditionally, Dr. Minshew said, researchers studying autism have concentrated on these behavioral areas.

Within the last 20 years, however, researchers began studying other aspects of thinking and brain functioning in autism, discovering that people with autism have difficulty in many other areas, including balance, movement, memory, and visual perception skills.

In the current study, Dr. Minshew and her colleagues administered a comprehensive array of neuropsychological tests to a group of children with autism. The researchers tested 56 autistic children, and compared their responses to those of 56 children who did not have autism. The children with autism were classified as having higher functioning autism-an I.Q. of 80 or above, and the ability to speak, read, and write. All of the children in the study ranged in age from 8 to 15 years. The purpose of the test array, Dr. Minshew said, was to determine whether there were any patterns in mental functioning unique to autism.

"We set out to find commonalities across a broad range of measures, so that we could make inferences about what's going on in the brain," Dr. Minshew said.

The researchers found that, across the entire series of tests, the children with autism performed as well as-and in some instances even better than-the other children on measures of basic functioning. Uniformly, however, they had trouble with complex tasks.