Many with autism also experience a condition that causes unusual sensory triggers, a new study indicates, such that hearing music or seeing a color may conjure a taste or a smell.
The condition known as synaesthesia involves people experiencing a “mixing of the senses.” Researchers report that it’s nearly three times as common in people with autism compared to those without.
The finding — which the study authors said came as a surprise — offers new clues to understanding the biology of autism and the experiences of many with the developmental disorder.
“I have studied both autism and synaesthesia for over 25 years and I had assumed that one had nothing to do with the other,” said Simon Baron-Cohen of the University of Cambridge, who led the study published Wednesday in the journal Molecular Autism. “These findings will re-focus research to examine common factors that drive brain development in these traditionally very separate conditions.”
For the study, 164 adults with autism and 97 without were screened for synaesthesia. Nearly 19 percent of those with autism and about 7 percent of the typically-developing individuals had the condition.
With synaesthesia, there are atypical connections in the brain linking areas that are not generally related. Much like autism, genes are thought to play a role in the condition but the exact cause is unknown.
Linking the two conditions offers new avenues to explore, the researchers said, in order to better understand how the brain develops and loses connections.
More immediately, however, understanding how common synaesthesia is among those with autism could have a more practical impact.
“People with autism report high levels of sensory hypersensitivity. This new study goes one step further in identifying synaesthesia as a sensory issue that has been overlooked in this population,” said Donielle Johnson, who worked on the study as graduate student at Cambridge. “This has major implications for educators and clinicians designing autism-friendly learning environments.”