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SDSU Researcher Paints Clearer Picture of Autism Development

SAN DIEGO, Tuesday, October 21, 2003 -- A San Diego State University researcher's discoveries published in this month's American Journal of Psychiatry offer a more comprehensive model for the development of autism. These findings could provide a wealth of benefits, including a better understanding of the development of the disorder, and may eventually contribute to the development future treatments.

Ralph-Axel Mueller, an SDSU psychology professor, found that when people with autism make simple finger movements, activity in the brain is more widely distributed than it is in healthy subjects. Mueller's discoveries suggest that, for people with autism, early-developing functions, such as simple movements, use up more brain resources and "crowd out" later-developing skills, such as language abilities and other executive functions. These discoveries suggest that autism is likely based on elementary abnormalities that occur early in a child's development.

"Autism is a very large and complex puzzle," Mueller said. "These findings could help us better understand the disorder and provide a clearer picture of how it develops."

For this study, Mueller used Functional Magnetic Resonance Imaging, technology that shows visual maps of brain function, to examine eight male patients with autism and eight control subjects that matched patients' age, gender and handedness. They performed finger press movements prompted by visually displayed six-digit sequences. Brain responses to the six-digit sequences were statistically compared to responses in single-digit displays in one experiment, and to regular six-digit sequences in another experiment. Autistic patients showed less activity in areas that were activated in normal comparison subjects, but more brain activity in areas that are normally not involved in such motor functions.

"From that we could conclude that patients with autism exhibit a scattering of brain functions," Mueller said. "These findings support the idea that during development, regions of the brain involved in simple tasks, such as motor control, require more brain tissue. These parts of the brain are then not available for later developing more complex functions. In other words, basic functions may 'crowd out' more complex functions, such as language."

A psychiatric disorder that affects about two out of 1,000 children, autism is characterized by poor language and social skills and a propensity for repetitive behavior. Early intervention programs that encourage autistic children to interact with their environment are believed to curb its long-term effects, but most children with autism still require special care throughout their lives.

San Diego State University is the oldest and largest higher education institution in the San Diego region. Since its founding in 1897, SDSU has grown to offer bachelor's degrees in 79 areas, master's degrees in 67 areas and doctorates in 14. SDSU's more than 34,000 students participate in academic curricula distinguished by direct contact with faculty and an increasing international emphasis that prepares them for a global future. For more information log on to www.sdsu.edu.

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