Audio-Visual Mismatch: A Main Sensory Disturbance in Autism Spectrum Disorders

Two weeks ago, researchers in the lab of Mark Wallace at the Vanderbilt Brain Institute  determined that children with autism spectrum disorders (ASD) have difficulty integrating audio and visual information, according to the study published in The Journal of Neuroscience.

The data are the first to strongly suggest that children with ASD exhibit deficits in multisensory function.  The lab looked specifically at the relationship between audio and visual cues, and found that children with autism have a larger temporal binding window (TBW).  This means that the brain has trouble integrating the visual and auditory events within a certain time period.  These findings may have implications in other groups with difficulty integrating multisensory stimuli, including dyslexia and schizophrenia.

A token sign of autism: children with hands over their ears. A possible explanation for this is the mismatch of audiovisual information, as the child is trying to eliminate one of the two stimuli.

To examine the audiovisual relationship, researchers looked at 32 normally developing children and 32 high-functioning children with autism.  The participants were given computer tasks involving simple stimuli such as flashes and beeps, and more complex stimuli like a hammer hitting a nail. Participants were asked whether the visual and auditory events happened at the same time.  Overall, it was found that the children with autism had more difficulty determining if the two stimuli occurred at the same time than the normally developing children.

One of the main components of ASD is the struggle to communicate, which includes not only recognition, but also comprehension, and verbalization. The recent data proves that the improper function of the TBW is a key factor of the sensory disturbance.  As this is the first data, more investigations into this audiovisual sensory disturbance must be done to further our understanding of ASDs.

To read the full article: http://www.jneurosci.org/content/34/3/691.full

Stevenson, Ryan A., et al. “Multisensory Temporal Integration in Autism Spectrum Disorders.” The Journal of Neuroscience 34.3 (2014): 691-697.

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