A simple sniff test can help diagnose autism in children, says a new research. Most people take a big sniff when something is pleasant and limit their breathing when they encounter a foul smell.
Researchers found that children with autism spectrum disorder (ASD) don't make this natural adjustment no matter how pleasant or awful the scent.
Professor Noam Sobel, of the Weizmann Institute of Science in Israel, said, "The difference in sniffing pattern between the typically developing children and children with autism was simply overwhelming."
Previous studies had indicated that people with autism have impairments in internal action models. The brain templates we rely on to seamlessly coordinate our senses and actions. But it wasn't clear if this impairment would show up in a test of the sniff response said Sobel.
The study involved 18 children with autism and 18 normally developing children with pleasant and unpleasant odors and measured their sniff responses. The average age of children in the study was seven.
Typically developing children adjusted their sniffing within 305 milliseconds of smelling an odor. Children with autism showed no such response.
The researchers reported that sniffing was associated with increasingly severe autism symptoms, based on social but not motor impairments.
"It's a semi-automated response. It does not require the subject's attention," said Liron Rozenkrantz, a neuroscientist at the Weizmann Institute of Science in Israel and one of the researchers involved with the study.
Based on the sniff response to unpleasant odors, the researchers were able to predict a child's diagnosis of autism with 81 percent accuracy.
"We can identify autism and its severity with meaningful accuracy within less than 10 minutes using a test that is completely non-verbal and entails no task to follow. This raises the hope that these findings could form the base for development of a diagnostic tool that can be applied very early on, such as in toddlers only a few months old. Such early diagnosis would allow for more effective intervention, said Sobel"
The study is published in the journal Current Biology