A team of researchers from the University of Utah and Harvard have reported using a brain-imaging test that looks at connections within the brain in order to distinguish people with autism from those without. In a recent trial, the researchers found that the test successfully identified the autistic brain more than 90% of the time.
The study involved 30 boys and men with high-functioning autism, ranging in age from 7 to 28, along with 30 typically functioning counterparts. All participants were given a specialized MRI test that measures the brain's structure, rather than where it "lights up" in activity. The researchers focused on two areas in the temporal lobe of the brain — the temporal gyrus (STG) and temporal stem (TS) — which are known to be involved in language, emotion and social skills.
The results showed that the autistic and non-autistic brain had measurable differences in circuitry in the white matter in these regions. Based on these differences, researchers were able to distinguish autistic people from those who were typically developing with 94% sensitivity, 90% specificity and 92% accuracy, according to the study published in Autism Research. The researchers replicated the results in a second sample of 12 males with autism and seven matched controls.
If these findings can be confirmed in a larger group of people — and, importantly, in children — the test could potentially help speed diagnosis. Until now, autism has been diagnosed only through a long process that involves observing behaviors including language, social interactions and physical movements. But if earlier diagnosis were possible, it could mean earlier treatment and intervention, which could in some cases even help prevent the development of autism altogether.
Other recent research using brain scans has revealed interesting structural differences in the autistic brain. In a study published in Science Translational Medicine, scientists found that in people with autism, the brain shows "too many tight connections in frontal-lobe circuits and too few long-distance links between the frontal lobe and the rest of the brain," as Healthland's Maia Szalavitz reported in November. Szalavitz explained:
The research links a variant of the CNTNAP2 gene to this particular type of rewiring in the brain. ... The gene produces a protein called CASPR1 and is active during brain development — mostly during frontal-lobe development. "During early development, it is localized to parts of brain that are 'more evolved' — areas where learning and language happen, the frontal lobes where really complex thinking takes place," says Ashlee Scott-van Zeeland, a postdoctoral fellow at the Scripps Translational Science Institute in La Jolla, Calif., and lead author of the study. "[It is] thought to help structure the brain." The gene also influences the development of reward regions of the brain, which are involved in motivation, pleasure and learning.
And in a study published in August in the Journal of Neuroscience, researchers at King's College London also reported using a 15-minute MRI scan to look at the structure of gray matter in brain regions related to language and social behavior in people with autism — the test was able to identify the autistic brain with about 90% accuracy.
While these findings are promising, they're preliminary. Researchers still need to show that the scans can distinguish between autism and other developmental disorders that involve the same brain regions, and they must also show that the tests can work in children.
Monday, December 6, 2010
Posted by BA Haller at 6:23 PM