Brains of autistic slower to react to sounds: study

By Andrew Stern

CHICAGO (Reuters) - The brains of autistic children react to sounds a fraction of a second slower than those of normal children, which may help explain the communication problems associated with autism, researchers said on Monday.

"What this does is it provides strong supporting evidence for the emerging theory that autism is a problem of connectivity in the brain," said Timothy Roberts, vice chairman of research in the Department of Radiology at Children's Hospital of Philadelphia.

Roberts and his colleagues had 30 autistic children age 6 to 15 listen to a battery of sounds and syllables while monitoring the tiny magnetic fields produced by the brain's electrical impulses.

The test employed a technique, called magnetoencephalography (MEG), in which a helmet-like device is used to detect and locate brain activity. Only around one hundred devices exist that can monitor the tiny magnetic fields, Roberts said in a telephone interview.

In comparison to the tenth of a second response time in the brains of normal children in the study, the autistic children's brains were anywhere from 20 percent to 50 percent slower to react.

Since a single syllable in a multisyllable word might take less than one-quarter of a second to say, Roberts said 1/20th of a second extra delay in the response time of the brains of autistic children may hamper their ability to comprehend.

"There could be abnormal routing or a lack of connectivity in the brain," he said in a telephone interview. "It may be like a highway with traffic making it hard to get through."

"We think this (delay) is a signature or a biomarker that could be used to stratify autism patients," since autism is a spectrum of disorders that afflicts people to vastly different degrees, he said.