A new technique to scan and measure three different parts of the brain could lead to earlier diagnosis of autism, according to the results of a small study from UAB published this week.

Psychology professor Rajesh Kana and former Ph.D. student Lauren Libero led the study, which used MRI to measure the anatomy, connectivity and chemistry of the brain. Past studies have found differences in these three areas in the brains of autistic subjects, but have not found one consistent marker.

But computers using information from all three scans and a decision tree designed by the researchers identified autistic subjects in more than 90 percent of cases. The results suggest that autism could be caused by a combination of brain abnormalities, Kana said.

"Here is a really complex disorder, autism," Kana said. "And maybe we don't have one magic bullet or one part of the brain responsible for this."

There are few conditions as perplexing as autism - a disorder that can affect communication, social skills and sensory processing. People may be mildly or profoundly affected by autism, and they may show some symptoms much more than others.

To diagnose the disorder now, doctors rely on observation and reports from parents and caregivers. There's no blood test or brain scan to definitely determine the diagnosis. Researchers and advocates say a definitive test could lead to better diagnosis and treatment for young children.

"It would be great if there was a neuroimaging scan to indicate the propensity to develop autism," said Bama Hager, staff member at the Autism Society of Alabama and the mother of an autistic teenager. "All evidence shows the earlier there is intervention, the better the outcome."

Autism is typically diagnosed between 18 months and four years of age. Parents may be the first to notice developmental delays and other differences, but it can be difficult to determine which children have autism and which ones are just a little behind. That uncertainty can lead to delays in diagnosis and treatment.

"Parents always hear grandma's theory that the child who isn't talking at two will develop speech by age four," Kana said.

Children diagnosed with autism typically receive speech, occupational and behavioral therapy, Hager said. Patients who receive therapy at early ages tend to do better in the long run. The combination brain scan could potentially lead to diagnosis for children younger than a year, Kana said.

Libero, a post-doctoral scholar at the University of California-Davis, said the next step is to expand the study to a larger group of subjects. Only 19 autistic patients and 18 control subjects participated in the initial study. Results of the UAB study appeared online this week in the journal "Cortex."

A larger study needs to include a wider variety of patients, including more women and autistic people with intellectual disabilities, Libero said. If the results of the smaller study are repeated in a larger group, it may lead to improvements in treatment along with diagnosis, she said.

"When we're looking at autism, we might actually be talking about different subtypes," Libero said. "That may lead to more tailored treatment."

The researchers are applying for funding from the National Institutes of Health to expand the study to more people.

"These are modestly funded studies," Kana said. "We need a lot of funding to do bigger studies. But with these modest resources, we have been able to get pretty interesting results."