How children respond with sniffs to different odors could be the basis of a test for autism, researchers in Israel report. Most people take a nice deep sniff to take in the sweet but subtle floral scent of a rose. But ducking into a port-a-potty at a crowded outdoor concert, we tend to do the opposite, rapidly limiting the flow of air through our noses.

But researchers have found that individuals with autism spectrum disorder (ASD) don’t make this instinctual adjustment like others do. Autistic children keep on sniffing the same way, no matter how nice or wretched the scent. Noam Sobel, of the Weizmann Institute of Science in Israel, added:

“The difference in sniffing pattern between the typically developing children and children with autism was simply overwhelming."

The findings indicate that a sniff test could be useful in the clinic. The researchers emphasize, however, that their test is in no way ready for that yet.

“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,” Sobel says. “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."

Earlier work had suggested that people with autism have deficits in “internal action models,” the brain templates we rely on to seamlessly coordinate our senses and actions. Until now tt was not clear if this impairment would show up in a test of the sniff response.

The most important question now, for Sobel is

“whether an olfactory impairment is at the heart of the social impairment in autism."

The researchers plan to test if the sniff-response pattern they’ve observed is specific to autism or whether it might show up also in people with other neurodevelopmental conditions.

Rozenkrantz et al. A Mechanistic Link between Olfaction and Autism Spectrum Disorder Current Biology,

_Top image depicts the measurement of nasal airflow while a child is presented with pleasant and unpleasant odors. Throughout the 10-minute study the children were seated comfortably in front of a computer monitor while viewing a cartoon. The nasal airflow measurement and the presentation of odorants were done using a modified pediatric nasal cannula and a custom built olfactometer. Credit: Ofer Perl _

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