New research is challenging the long-held belief that autism affects only those regions of the brain that control social interaction, communication, and reasoning -- suggesting, instead, that the disorder affects the entire brain.

The government-funded study found that even highly functioning autistic children had difficulty when asked to perform a wide range of complex tasks involving other areas of the brain.

This suggests different parts of the autistic brain have difficulty working together to process complex information. This may be the driving component of autism, the researchers say.

The study was funded, in part, by the National Institute of Child Health and Human Development (NICHD) of the National Institutes of Health.

“These findings suggest that a further understanding of autism will likely come not from the study of factors affecting one brain area or system, but from the study of factors affecting many systems,” says NICHD director Duane Alexander, MD.

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Earlier Findings in Adults

Autistic children and adults typically have problems with social interactions and verbal and nonverbal communications. They tend to exhibit repetitive behaviors or narrow, obsessive interests. These three behaviors are the basis of the diagnosis of autism.

It is increasingly clear, however, that other areas of brain function are affected as well, including balance, movement and memory.

In earlier research, Nancy J. Minshew, MD, and colleagues offered evidence to support the whole-brain hypothesis in studies looking at autistic adults.

Autistic adults they tested had difficulty performing certain complex tasks that involved different areas of the brain working together.

In the newly published study, the research team compared highly-functioning autistic children to nonautistic children with similar IQs and ages in an effort to confirm their findings in adults.

All the children in this study were aged 8-15, all had IQs of 80 or above, and all could speak, read and write.

Across a battery of tests, the autistic children did as well as or better than then nonautistic children when asked to perform basic tasks.

But they scored much worse when asked to perform complex tasks.

Autistic children tended to be very good at remembering specific details of a story, for example, but had difficulty comprehending its meaning.

Or they performed well on tests measuring spelling and vocabulary, but had trouble understanding complex figures of speech.

“We see this with our patients,” Minshew says. “If you use an expression like ‘hop to it,’ a child with autism may literally hop.”

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New Approaches to Treatment

Diane L. Williams, PhD, a researcher on the study, tells WebMD the findings have implications for both the future study and treatment of autism.

“The more we understand about autism and the brain, the better we can design both effective and efficient therapy programs,” she says.

Williams questions the long-term effectiveness of highly-structured behavioral interventions that focus solely on teaching children missing social skills. For example, communication might be taught as a series of discrete skills, such as making eye contact, not changing the topic, and not interrupting.

This type of instruction may work in structured settings, says clinical psychologist Steven Gutstein, PhD, but not in the real world.

“In the real world the topic may be changed 10 times in a typical conversation, and everyone interrupts,” he says.

Gutstein is director of the Connection Center in Houston, an autism treatment facility which focuses on teaching children how to think in more flexible ways.

“People with autism learn to avoid uncertainty at all costs, but when they do this they also avoid the opportunity for cognitive growth and development,” he says. “We try to gradually and safely introduce situations of challenge, uncertainty, variation, and choice to teach autistic children to be problem solvers.”

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By Salynn Boyles, reviewed by Louise Chang, MD

SOURCES: Williams, D. Child Neuropsychology, August 2006; online edition. Diane L. Williams, PhD, assistant professor, department of speech pathology, Duquesne University, Pittsburgh. Nancy J. Minshew, MD, professor of psychiatry and neurology, University of Pittsburgh School of Medicine. Steven Gutstein, PhD, clinical psychologist; director, Connection Center, Houston; president, Foundation for Autism Research and Remediation.