A team of researchers has suggested that the way children sniff different aromas can form the basis of a test for autism.
People inhale the delightful aroma of a bouquet of roses longer than the foul stench of rotting fish, but the results of tests on 36 children showed that there appeared to be no such difference in children with autism, the BBC reported.
The National Autistic Society said smell could eventually become an additional tool for testing for autism.
One of the researchers, Liron Rozenkrantz, said children normally altered the depth of their sniffing to the odours, adding that children with autism didn't show this modulation at all, they took the same sniff for the smell of shampoo as they did for rotten fish.
The team developed a computer program that could detect autism in the group of children with 81 percent accuracy. They also showed that the more severe the symptoms of autism, the longer the children inhaled the unpleasant smells.
The earlier autism is diagnosed, the sooner children can get access to behavioural or educational interventions.
The team at the Weizmann Institute of Science said that one of the advantages of a sniffing test was that it did not rely on the child being able to communicate so it may be useful at a very early age.
Rozenkrantz added that before they can use it as a diagnostic test, they need to know at what age children start to develop a sniff response in the general population.
The study appears in the journal Current Biology.