Can we test for autism with smell?

Chuck Bednar for – @BednarChuck

How a child reacts to smelling something like a rose or a cup of sour milk could predict whether or not they have autism, according to a new study from researchers at the Weizmann Institute of Science in Israel and published Thursday in the journal Current Biology.

According to, the authors recruited 36 children, 18 of whom had autism and 18 which did not, and exposed them to a series of different smells ranging from pleasant fragrances such as roses or shampoo to foul odors such as spoiled milk or rotten fish.

The smells were delivered to the subjects using an olfactometer, a small tube that fit into their nostrils while a second tube measured the amount of air that each youngster breathed in as they were exposed to each smell.

The researchers discovered that non-autistic children took longer sniffs for pleasant smells and shorter ones for unpleasant ones. Autistic children, on the other hand, showed no change in their breathing in response to either type of smell.

Potential for a diagnostic tool?

“What we measure, the sniff response, is quite intuitive– adults and children with typical development react similarly,” lead author Liron Rozenkrantz, a doctoral student in neurobiology at the Weizmann Institute, told, adding that the difference between autistic and non-autistic children was striking.

At this point, it is uncertain if the autistic children did not have a sniff response because they perceive odors in different ways than non-autistic children, or because they do not have control over the behavior. The study provides scientific evidence to support anecdotal reports from the parents of autistic kids regarding this behavior, Rozenkrantz told the website.

The test took approximately 10 minutes, did not require the participants to answer any questions and allowed them to simply wear the device while watching cartoons. The study authors said that their test could correctly identify autism in 12 of the 18 subjects, while also correctly concluding that 17 of the 18 control children did not have the developmental disorder.

Dr. Paul Wang, senior vice president and head of medical research for the research and advocacy group Autism Speaks and who was not involved in the research, told CNN that it is “way too early to say whether this could be helpful in diagnosing autism,” and that the device would have to be tested in more children and identify autism in more than two-thirds of children to be used as a diagnostic tool.


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