Children with high-functioning autism spectrum disorder (ASD) struggle to interpret the visual and auditory cues associated with speech but appear to outgrow this deficit in adolescence, says a study by researchers at the Albert Einstein College of Medicine of Yeshiva University. The study was published online on August 28, 2013 in the journal "Cerebral Cortex."
"This is an extremely hopeful finding," said John Foxe, Ph.D., lead author of the study and director of research of the Children's Evaluation and Rehabilitation Center at Einstein. "It suggests that the neurophysiological circuits for speech in these children aren't fundamentally broken and that we might be able to do something to help them recover sooner."
A previous study demonstrated that autistic children process multi-sensory information such as sight, sound, and touch differently than typical children, making it more difficult for them to pickup and understand cues in conversations. The current study analyzed whether high functioning autistic children could integrate the visual and audio cues of speech. Research tested 222 typical and high-functioning autistic children aged 5 to 17 to measure their ability to understand speech.
The tests included:
- measuring how well children could understand speech in spite of background noise that increased in volume
- Audio recordings of simple words that were played for the children
- A video without audio shown of a speaker who mouthed words
- Both video and audio recordings
Dr. Foxe commented that in noisy settings with a lot of people talking, people rely on facial and auditory cues to understand what someone is saying. "You get a surprisingly big boost out of lip-reading, compared with hearing alone," said Dr. Foxe. "It's an integrative process."
- In an audio alone test, the autistic children performed nearly as well as typical children in all age groups and background levels
- In the video alone test, the performance of autistic children was significantly worse than typical children. “The typically developing children didn't perform very well, either," Dr. Foxe said. "Most people are fairly terrible at lip-reading"
- In a video and audio test, autistic children ages 6 to 12 performed much worse than typical children, especially at higher noise levels, however, both typical and autistic children showed no differences in performance
"In adolescence, something amazing happens and the kids with ASD begin to perform like the typically developing kids," said Dr. Foxe. "At this point, we can't explain why. It may be a function of a physiological change in their brain or of interventions they've received, or both. That is something we need to explore."
The scientists admit there are some limitations to their study. "Instead of doing a cross-sectional study like this, where we tested children at various ages, we would prefer to do a longitudinal study that would involve the same kids who'd be followed over the years from childhood through adolescence," Dr. Foxe said. "We also need to find a way to study what is happening with low- and mid-functioning children with ASD. They are much less tolerant of testing and thus harder to study."
Dr. Foxe says that the study highlights the need for more effective therapies that can help autistic children integrate visual and audio signals in speech.