Brain scans that measure how strongly different areas of the brain are connected revealed enough differences between autistic and normal children to differentiate the two with about 90 percent accuracy.

It has been known for some years now that autistic brains are abnormally large, but the inconsistent way in which the brains of different subjects were enlarged has made it difficult for scientists to use brain scans to systematically detect autism. Now, scientists at Harvard’s Children’s Hospital have used the data crunching power of computers and electroencephalograms (EEG) to solve the problem, successfully detecting autism in children as young as two years old. The study is the latest in several ongoing efforts to reliably and relatively easily detect the disorder through brain imaging.

The goal of the study was to see if the EEG scans could accurately differentiate between normal children and those clinically diagnosed with autistic spectrum disorder. It included 1,304 subjects between 1 and 18 years of age: 463 autistic and 571 controls. Software was used to analyze the EEG scans and detect any patterns that might be found only in the scans of the autistic children. They found 33 such patterns and used them to assign the children to each group. In 2- to 12-year-olds the method correctly identified 88.5 percent of controls and 86 percent of autistic children. Accuracy was even higher when limited to shorter ranges of age: in 2- to 4-year-olds it identified 90.6 percent of controls and 98.1 percent of autistics; 4- to 6-year-old, 90.9 percent of controls and 99.1 percent of autistics.

The study was published recently in BMC Medicine.

Autism is typically diagnosed with a psychiatric examination at around two years of age, the youngest age at which the current study was able to detect the disorder. Dr. Frank Duffy, the team’s lead scientist, acknowledges that more work needs to be done and the hope is that EEG scans will one day provide a tool to detect autism earlier. Another recent study shows that this is possible. Measuring differences in the brain’s white matter, another group of scientists were able to differentiate between normal children and those with autism spectrum disorder as young as six months old.

Autism is a complex disorder that continues to perplex researchers and clinicians. It is thought to be about 90 percent genetic, but environment also plays an important role. As yet, there is no cure. However, a diagnostic test that could detect the disorder at the earliest possible age could serve as a supportive measure for treatment, and hopefully one day, a cure.

[image credits: PDResources and BMC Medicine]
images: PDResources and BMC Medicine

Peter Murray was born in Boston in 1973. He earned a PhD in neuroscience at the University of Maryland, Baltimore studying gene expression in the neocortex. Following his dissertation work he spent three years as a post-doctoral fellow at the same university studying brain mechanisms of pain and motor control. He completed a collection of short stories in 2010 and has been writing for Singularity Hub since March 2011.