A joint research project between Harvard University and University of Utah scientists has resulted in the development of a new biological test for autism.
The test uses magnetic resonance imaging (MRI) to measure deviations in brain circuitry, and is an objective way of identifying individuals with the disorder that could someday replace the subjective methods that are currently used.
Today, Autism is diagnosed with clinical interviewing and observation of the child for another hour or so. It is hoped that this MRI will provide a more definitive way of determining autism early on, by pointing to something in the brain that is biologically based
Dr. Lange, Nicholas Lange, ScD, associate professor of psychiatry at Harvard Medical School, was the senior study author, and with Janet E. Lainhart, MD, from the University of Utah, Salt Lake City, and other colleagues, they set out to explore the hypothesis that study of white matter microstructure in regions of the brain responsible for language, emotion, and social cognition would further the understanding of autism neuropathology.
Diffusion tensor imaging measures white matter microstructure by mapping directions of water diffusion in a local brain tissue frame of reference.
Other types of MRI scans, such as those that compare the sizes of various parts of the brain between healthy individuals and individuals with a particular brain disorder,have not shown much difference in autism.
The researchers took white matter microstructure measurements from the superior temporal gyrus and temporal stem in 30 males aged 7 to 28 years who were diagnosed as having autism by the standard subjective scoring system and in 30 matched controls.
In the subjects with autism, less information was being exchanged in the key areas of the brain responsible for language, social functioning, and emotional behavior.
The test was able to detect autism in this study with 94% accuracy, by identifying less organized wiring.
The findings correlate with the clinical impairments of autism, such as the inability to read body language, and the resulting lack of friendships.
“There appears to be a lack of ordered directional diffusion along the axons to help them make those connections, and we were able to pinpoint just where this is occurring through this brain circuitry imaging,” Dr. Lange noted.
Dr. Lange is hopeful that this test will someday be used clinically to make accurate and prompt diagnoses in young children.
Early diagnosis may allow intensive, individualized, and early interventions to minimize the impact of the disorder.
This test is NOT YET ready for clinical use. At the present time, child and adolescent clinicians must continue to rely upon careful clinical assessments to diagnosis Autism.
The study was sponsor by the National Institutes of Mental Health. Dr. Lange and Dr. Lainhart have disclosed no relevant financial relationships.
Autism Res. Published online November 29, 2010.