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Simple smell test might detect autism


Date: September 27, 2015
Weizmann Magazine Vol. 8

Weizmann Institute scientists have revealed an intriguing connection between the sense of smell and autism spectrum disorder— findings that may contribute to early diagnosis of the disorder.

Prof. Noam Sobel, Head of the Department of Neurobiology, and research student Liron Rozenkrantz measured reactions in children to odors by gauging the sniffing response. “We inhale more deeply when we encounter a pleasant odor; less deeply for a bad one,” says Rozenkrantz. “This activity is controlled, in part, by the cerebellum, which also plays a role in autism.”

A total of 36 children were enrolled in the study: 18 with autism spectrum disorder and 18 typically developing. It was conducted with Prof. Ditza Zachor (who is an M.D.), Head of the Autism Center at Assaf Harofeh Medical Center. During the 10-minute experiment, each child was exposed to a variety of odors—both pleasant and unpleasant. The researchers measured their breathing patterns in each instance. The measurements showed that the control group had normal sniffing responses: deeper breaths for pleasant odors and shallower breaths for unpleasant ones. The children with autism had a different response: they didn’t modify their breathing.

The researchers were able to ascertain with 81 percent accuracy—based on sniffing-response data alone—whether a child was autistic. The more severe the autism, the more atypical the sniffing response, showing up as a longer inhale in response to an unpleasant odor.

Because the test does not require either the use of language or particularly high cognitive skills, the scientists hope that in the future it may be used to assist in the diagnosis of autism at an earlier age than is possible today.


Prof. Noam Sobel is funded by Adelis Foundation, The Norman and Helen Asher Center for Brain Imaging, which he heads, The Azrieli National Institute for Human Brain Imaging and Research, which he heads, The late H. Thomas Beck, The Nella and Leon Benoziyo Center for Neurosciences, which he heads, The Carl and Micaela Einhorn-Dominic Institute for Brain Research, which he heads, Nadia Jaglom Laboratory for the Research in the Neurobiology of Olfaction, Lulu P. & David J. Levidow Fund for Alzheimer's Disease and Neuroscience Research, James S. McDonnell Foundation 21st Century Science Scholar in Understanding Human Cognition Program, Rob and Cheryl McEwen Fund for Brain Research. Prof. Sobel is the incumbent of the Sara and Michael Sela Professorial Chair of Neurobiology.