"Imagine the way you might smell a rose. Youd take a nice big sniff to breathe in the sweet but subtle floral scent. Upon walking into a public restroom youd likely do just the oppositeabruptly limiting the flow of air through your nose. Now researchers reporting in the Cell Press journal Current Biology on July  have found that people with autism spectrum disorder ASD dont make this natural adjustment like other people do. Autistic children go right on sniffing in the same way no matter how pleasant or awful the scent. The findings suggest that nonverbal tests related to smell might serve as useful early indicators of ASD the researchers say. The difference in sniffing pattern between the typically developing children and children with autism was simply overwhelming says Noam Sobel of the Weizmann Institute of Science in Israel. Earlier evidence had indicated that people with autism have impairments in internal action models the brain templates we rely on to seamlessly coordinate our senses and actions. It wasnt clear if this impairment would show up in a test of the sniff response however.  To find out Sobel along with Liron Rozenkrantz and their colleagues presented  children with ASD and  normally developing children  boys and  girl in each group with pleasant and unpleasant odors and measured their sniff responses. The average age of children in the study was . While typical children adjusted their sniffing within  milliseconds of smelling an odor the researchers report children on the autism spectrum showed no such response. That difference in sniff response between the two groups of kids was enough to correctly classify them as children with or without a diagnosis of ASD  of the time. Moreover the researchers report that increasingly aberrant sniffing was associated with increasingly severe autism symptoms based on social but not motor impairments. The findings suggest that a sniff test could be quite useful in the clinic although the researchers emphasize that their test is in no way ready for that yet. We can identify autism and its severity with meaningful accuracy within less than  minutes using a test that is completely nonverbal 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. The researchers now plan to test whether the sniffresponse pattern theyve observed is specific to autism or whether it might show up also in people with other neurodevelopmental conditions. They also want to find out how early in life such a test might be used. But the most immediate question for Sobel is whether an olfactory impairment is at the heart of the social impairment in autism. Current Biology Rozenkrantz et al. A Mechanistic Link between Olfaction and Autism Spectrum Disorder httpdx.doi.org.j.cub...  Current Biology published by Cell Press is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology both by publishing important findings of general interest and through highly accessible front matter for nonspecialists. For more information please visit http To receive media alerts for Current Biology or other Cell Press journals contact presscell.com mailtopresscell.com."