People with autism are more likely to also have synaesthesia, a new research suggested on Wednesday.
The new findings were published in the journal Molecular Autism.
According to researchers from Cambridge University, synaesthesia involves people experiencing a "mixing of the senses," for example, seeing colours when they hear sounds, or reporting that musical notes evoke different tastes.
Autism is diagnosed when a person struggles with social relationships and communication, and shows unusually narrow interests and resistance to change.
The new research found that whereas synaesthesia only occurred in 7.2 percent of typical individuals, it occurred in 18.9 percent of people with autism.
The scientists tested 164 adults with an autism spectrum condition and 97 adults without autism. Then they confirmed the prediction that, if both autism and synaesthesia involve neural over-connectivity, synaesthesia might be disproportionately common in autism.
"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 Professor Simon Baron-Cohen, who led the research. "These findings will re-focus research to examine common factors that drive brain development in these traditionally very separate conditions."
"This new research gives us an exciting new lead, encouraging us to search for genes which are shared between these two conditions, and which might play a role in how the brain forms or loses neural connections," he said.