SALT LAKE CITY — The communication between the left and right sections of the brain in people with autism is out of synch when you look at magnetic resonance images. That detectable communication lapse hints that MRIs might one day become a valued tool for early and objective diagnosis of children with the disorder, according to University of Utah researchers.
What's perhaps most telling in the study, which will be published online in Cerebral Cortex on Oct. 15, is where communication seems to break down: those parts of the brain associated with motor skills, attention, facial recognition and social functioning, which are all areas affected by autism.
The research, led by Dr. Jeffery S. Anderson, U. assistant professor of radiology, found that MRIs of people who do not have autism do not show the same communication lapses.
The brain itself is not structurally different, aside from an increased brain size in children with autism. It is in how the parts of the brain talk to each other that differences have been found, said Jason Druzgal, a senior author on the study who recently left the U. for a job as assistant professor of radiology at the University of Virginia. "If you just put them in the scanner and do what you do in a clinical MRI, it wouldn't show any difference," he said.
But a functional MRI can measure changes in blood oxygenation and that's a "proven surrogate" for underlying neurological activity. Using that, researchers took a reading of blood oxygenation every two seconds while the subject did nothing, then employed a new data analysis technique that found "the firing of the neurons isn't happening as synchronized in someone who is autistic as in others." Areas where that's most noticeable are implicated as abnormal in the brains of autistic people by other research, as well.
"We still don't know precisely what's going on in the brain," Dr. Janet Lainhart, U. associate professor of psychiatry and pediatrics and the study's principal investigator, said Tuesday afternoon. But it shows the connections between different parts of the brain are abnormal" in subjects with autism.
Future research, predicts Lainhart, will also look at communication anterior to posterior, not just between left and right sides of the brain. And one of the goals is to find a biological way to diagnose different subtypes of autism. That may show not only which treatments will help which people, but also what "trajectory" the disorder might take in individual children.
"Right now, the treatments are very nonspecific. One thing that would be helpful would be to have good information about the clinical course a child appears to be on. Some get better, some worse, some plateau. ...When you understand it at a biological level, you can envision how the disorder develops, what are the factors that cause it and how can we change it," she said.
While other studies have shown connectivity abnormalities in autism, this one is the first to image the entire brain with MRI instead of focusing on specific pathways. To do it, researchers imaged 80 autism patients ages 10 to 35. The results will be added to an ongoing long-term study that is following 100 patients.
The collaborative autism imaging research group includes researchers in departments of psychiatry, radiology and pediatrics, the Neurosciences Program, the Scientific Computing and Imaging Institute and The Brain Institute at the U., as well as collaborators at Brigham Young University, the University of Wisconsin and Harvard University.