Autism Diagnosis Can Be Helped By New Smell Test: Study

It may be possible to diagnose autism in children by measuring their reaction to smells, according to a new study that found a marked difference in the reaction to odors from children with the disorder, compared to those without it.

While most people automatically inhale a pleasant smell deeply, and seek to limit their breathing in order to avoid unpleasant ones, autistic children do not make this distinction, the study, published in the journal Current Biology, found.

Researchers measured the time it took children to react to pleasant and unpleasant smells, using a device called an olfactometer, which delivered different scents through a small tube that fit into nostrils. A second tube measured how much air the children were breathing in as they were exposed to each odor.

The study used a small sample group, comprising 36 children, 18 of whom were diagnosed with autism, and 18 who were more typically developed, and exposed them to smells including sour milk, rotten fish, soap and roses.

Typically developing children adjusted their sniffing very quickly -- within about 305 milliseconds -- while children diagnosed with autism reacted much slower. Researchers were not told which children had been diagnosed with autism and which had not, but using the test were able to identify the children on the spectrum 81 percent of the time, the study reported.

If the findings are substantiated by further research, the technique could help to diagnose children sooner. This could afford autistic children the opportunity to undergo treatment that could significantly improve their condition, which would not be as effective when they were older.

“We hope that it can be used as a diagnostic marker to diagnose autism at a very young age,” Liron Rozenkrantz, a neuroscientist at the Weizmann Institute of Science in Israel and one of the researchers involved with the study told the New York Times. “This is a nonverbal measure, and it only requires breathing.”

Lucia Murillo of the advocacy group Autism Speaks told Voice of America that early intervention in dealing with autism can be highly beneficial to diagnosed children and their families.

“Definitely, the earlier we can diagnose a child, the better,” she said, “simply because you’re able to work on some of the delays or weaknesses a child might have and use the strength they have to improve their skills.”

The idea that autistic children may react differently to sensory stimuli is not particularly unusual. Children with autism spectrum disorder often have either an exaggerated or a numbed response to sight, sound and touch. This behavior is so common that it's one of the diagnostic criteria for the disorder, according to CNN.