Sniff Test Could Identify Autism in Young Children

One of the challenges in treating autism spectrum disorder (ASD) is diagnosing people early so that they can receive the most effective interventions. A new study may lead to a straightforward method for identifying ASD at a young age. The study, from the Weizmann Institute of Science in Israel, finds that the way children with ASD use their noses is different than that of typically developing children. When most people smell something pleasant, they continue to sniff, but when they encounter an unpleasant odor, they stop. The researchers discovered that children with ASD do not follow this same pattern. The findings may lead to a method for identifying ASD that does not rely on verbal communication.

Evidence exists that people with ASD have impaired “internal action models,” which are brain templates that unconsciously link sense and action. The researchers investigated how these internal action models relate to olfactory functions by conducting a sniff test. Thirty-six children with an average age of seven years participated in the study; half had ASD and half were typically developing. The research team presented the children with pleasant and unpleasant odors and measured the children’s responses to the scents.

Typically developing children adjusted their sniffing within 308 milliseconds of smelling an odor. Children with ASD did not demonstrate the same response—they did not adjust their sniffing at all when they encountered new odors. Based on the test results of the sniff test, the researchers accurately classified children as autistic or typically developing 81 percent of the time.

“The difference in sniffing pattern between the typically developing children and children with autism was simply overwhelming,” stated Noam Sobel of the Weizmann Institute of Science. “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.”

The findings could lead to an early diagnostic tool for toddlers and infants, which would help them access critical early interventions. However, the researchers state that this test requires more research before it is used for diagnosis.

This research is published in the journal Current Biology.