A sniff test can predict autism with an accuracy of 81 percent, according to a new study that could help provide relief to those youth with the disorder. Children with autism respond differently than their peers to smells, both pleasant and unpleasant, researchers found.
Autistic children respond in an atypical fashion to many external stimuli, including a wide variety of senses. The disorder is characteristically marked by an inability to normally process social interactions.
"Since we know that many children with autism are hypersensitive to touch, sound, taste and visual stimuli, it is especially interesting that they seem not to be responsive to odor in the same fashion," Glen Elliott from Children's Health Council, a psychiatrist not involved in the study, said.
Researchers examined 18 children diagnosed with autism spectrum disorder (ASD) and the same number without the disorder. The subjects were exposed to 10 pleasant smells, such as shampoo or flowers, as well as 20 unpleasant smells, including rotten fish and sour milk.
They found that children without ASD "generated a typical adult-like sniff response within 305 ms of odor onset, [while] ASD children had a profoundly altered sniff response, sniffing equally regardless of odor valance. This difference persisted despite equal reported odor perception and allowed for 81 percent correct ASD classification based on the sniff response alone."
And more unusual sniff responses were associated with increasingly severe ASD, they said, specifically with social but not motor impairment. "These results uncover a novel ASD marker implying a mechanistic link between the underpinnings of olfaction and ASD and directly linking an impaired IAM with impaired social abilities," they report.
Autism is diagnosed based on behavior, rather than specific chemical characteristics or genetic mutations.
The disorder was seen in populations throughout history, but it was only recognized in a modern light in 1938. That year, Hans Asperger of the Vienna University Hospital first began a serious study of the syndrome which now bears his name. Five years later, the word autism was first used in its modern sense, and the disorder gained recognition as a distinct disorder in the 1960s. Genetics was once believed to play a small role in the disorder, although health officials now recognize ASD as being highly hereditary.
Autism is now being recognized as a disorder that affects the entire body, and modern treatments are focusing more and more on a whole-body approach to health. No one treatment method works for everyone, and care of each patient is now customized to the care of the individual.
"Treatments can divided into nonmedical interventions, which include behavioral and educational approaches as well as sensory, communication and other therapies, and biomedical treatments, such as diet modifications, addition of vitamins and minerals, gut treatments, immune system regulations and others," the Autism Society reports.
This new study could help medical researchers better understand autism, and develop new treatment methods. Because the sense of smell is so vital to interactions between human beings, researchers believe it may be possible that some of the social challenges faced by people with autism may stem from this altered state of sensing odors.
Although the results are intriguing, the small sample size of 36 children leaves significant uncertainty in the final results of the study.
Analysis of the sense of smell in children with ASD was detailed in the journal Current Biology.
Photo: Becky Wetherington | Flickr
