According to a new study published in Current Biology, a ‘sniff test’ may be able to help with the early diagnosis of autism, as researchers have discovered that children with autism are unable to adjust the way they deal with pleasant or bad smells.
When we smell something pleasant, we’re likely to inhale more deeply in order to take advantage of the nice aroma. Conversely, when faced with a nasty smell, we tend to hold our breath and restrict our exposure to it. This new study, conducted by Noam Sobel at the Weizmann Institute of Science in Israel, found that children who had been diagnosed with autism were unable to make this kind of adjustment. Whether they’re exposed to a pleasant or bad odour, they sniff them in the same way.
At the moment, there is no medical test for autism; diagnosis relies on developmental screening, where the child is assessed according to how they move, speak, learn and behave. However, Sobel and his colleagues believe that they may have discovered a measurable marker for autism, which could ultimately lead to the development of a test.
Following on past studies, which suggested that children on the autism spectrum have impairments in the areas of the brain responsible for sensory and motor coordination, Sobel aimed to determine whether sniff response would differ in children with autism. His study was based on conducting sniff tests with 18 children diagnosed with the condition, and comparing them to the results of 18 children without the disorder.
The team created a test which allowed them to deliver a selection of odours to the two groups while measuring their sniff response. By determining their nasal airflow, they were able to assess the children’s response to pleasant aromas such as roses and shampoo, and unpleasant aromas such as rotten fish and sour milk. They discovered that children without autism were able to adjust their sniff response almost immediately, while the autistic children didn’t adjust their response at all. By monitoring these differences, the researchers were able to identify whether the children had been diagnosed with autism or not with 81% accuracy. Furthermore, it was found that the more abnormal the sniffing response, the more severe the autistic symptoms.
Of course, while this research does give hope that a sniff test could soon be used to diagnose autism, the team have indicated that further studies are needed to confirm their findings.