Autistic children demonstrate measurable sound processing delays

Magnetoencephalography technology used to study abnormalities in auditory and language processing of autistic children has demonstrated measurable delays, according to a study presented at the RSNA meeting.

The study, funded by the National Institutes of Health and the Nancy Lurie Marks Family Foundation, subjected 64 autism patients, aged six to 15, to audio stimulation in the forms of beeps, tones in pairs, vowels, and sentences. It compared the audio processing time of these children with a control group of age-matched nonautistic children and found a significant delay in processing time.

"It's the real-time nature of this technology that gives us some significant insights," said presenter Timothy Roberts, Ph.D., vice chair of research in the radiology department at Children's Hospital of Philadelphia.

Magnetoencephalography (MEG) enabled researchers to detect delays in the pattern of audio processing of autistic children and to quantify and track these delays. Autistic children, for example, were on average 20 msec late in processing the sound of a beep. These brief latencies create a cascade of delays, leading to abnormal processing of auditory stimuli, Roberts said.

In using vowels as audio stimulus, researchers found that autistic children not only processed sounds more slowly but also processed a change in detection of sound more slowly, with an average of 35 to 50-msec delays.

"The result is a significant delay in the simplest hearing detection task across all of the children with autism," Roberts said. "Signals that move in one area of the brain move more slowly -- they're stuck in traffic."

Although there are only 100 MEG centers worldwide, researchers hope to continue their study of auditory and language processing in autistic children. The results of such studies could help classify different types of autism and could even affect therapy.

In the future, such studies could detect autism as early as the age at which infants begin processing language, Roberts said. This could have enormous impacts on treatment, perhaps using the technology to slow audio input to autistic infants, helping them to hear and process language the way nonautistic babies would.

Already, MEG technology has successfully made recordings of an 18-month-old baby.