High Accuracy MRI Brain Scan Can Detect Autism
The earlier autism is diagnosed, the better the intervention by health care experts. Because of this, scientists are striving to find an accurate objective test that can detect physical signs of the disorder so that children can be diagnosed and begin treatments sooner. Today, researchers from Harvard Medical School and the University of Utah revealed a brain-imaging test that has proven to be about 94% accurate in early trials.
MRI Measures Water Diffusion in the Brain
Autism, which is thought to affect about 1 in every 110 children, is characterized by difficulty with communication, learning and social interaction. The average age at diagnosis is 3 years old. Current diagnoses are based on subjective characteristics outlined in “The Diagnostic and Statistical Manual of Mental Disorders.”
The test is based on a magnetic resonance imaging (MRI) screen and uses a technique known as diffusion tensor imaging. The scientists were basing their study on the hypothesis that white matter microstructure in the regions of the brain responsible for language, emotion, and social cognition could lead to an understanding of the neuropathology of autism. Diffusion tensor imaging measures this by mapping the direction of water diffusion inside the brain.
For the study, Nicholas Lange, associate professor of psychiatry at Harvard Medical School and director of the Neurostatistics Laboratory at McLean Hospital (Massachusetts), and Dr. Janet Lainhart of the University of Utah recruited 30 men between the ages of 8 and 26 who were diagnosed with high-functioning autism and 30 men without the disorder. They all underwent MRI scans of the brain.
In a typical, normally-developing person, water flows in an organized manger in the left side of the brain and flows in a disorganized way in the right side. In the men with autism, the MRI scans revealed that the situation was reversed. "Out of the 30 [men with autism] that we had, we were able to correctly distinguish 28 of them," said Lange – a 94% accuracy rate.
For validation, the researchers repeated the study with a second group of 19 men, 7 of whom had autism. They were able to correctly identify all of the autistic men. According to the researchers, the test has also proven accurate in females, children younger than 8 and in adults older than 26.
The MRI scan will have to undergo further trials before it can be approved for general use. And it isn’t likely to replace the subjective tests any time soon, says Lange, but it could be used to examine a patient displaying some symptoms of the disorder.
The study was published online November 29 in the journal Autism Research.