Autism involves not only language and social difficulties but widespread brain changes affecting many aspects of behavior and thinking, scientists at the University of Pittsburgh have found.
"This is a big change in the way most people have thought about autism," said Dr. Duane Alexander, director of the National Institute of Child Health and Human Development.
Dr. Nancy Minshew and colleagues Diane Williams and Gerald Goldstein of the University of Pittsburgh School of Medicine conducted a comprehensive neuropsychological study of 56 high-functioning autistic children ages 8 to 15 and an equal number of nonautistic peers.
The autistic group was found to have deficits in many brain functions, including sensory and motor skills, attention, problem-solving and language.
"And it affects a broad range of abilities in each of these domains," said Minshew, a professor of psychiatry and neurology.
The study appears in the journal Child Neuropsychology.
Researchers found that the autistic children had difficulties processing information on sensory, motor, language, memory and reasoning areas. But more basic sensory abilities such as touch, pain, position and vibration were not affected.
The scientists suspect autism is caused by the brain's inability to integrate complex information from various parts of the brain.
For instance, an autistic child may have no problem finger-tapping, but tends to have trouble with a more complex motor task such as drawing or using scissors.
The researchers hope that their findings will help lead to autism treatments that repair the brain's faulty circuitry.