Most doctors and nurses cringe when they think about performing a “whiff test,” but researchers from the University of Cincinnati don’t. They are the proud inventors of the Sniff Magnitude Test (SMT) for the diagnosis of neurological diseases like Alzheimer’s.
A new medical device in development by University of Cincinnati researchers may sniff out olfactory disorders that could be an early warning of Alzheimer’s disease, Parkinson’s disease and other problems outside the typical sensory loss associated with aging. The Sniff Magnitude Test (SMT), an invention of UC Psychology Professor Robert Frank and Professor Emeritus Robert Gesteland of the UC Department of Cell Biology, is now under further development with the WR Medical Electronics Company in Stillwater, Minn. The company will manufacture and market the test.
The Sniff Magnitude Test project, a creation that was seven years in the making, was awarded a total of $1,340,098 from the National Institutes of Health in developmental funding. UC Psychology Professor Robert Frank says that in the near future, UC researchers will begin testing five different prototypes of the SMT built by WR Medical Electronics. Currently, Frank says an earlier model of the SMT is being tested in a high-profile clinic in Germany as well as at the University of Pennsylvania. Frank says the SMT customer base would be primarily otolaryngologists and neurologists.
“The whole test is based on the very simple observation that when you sniff and you detect a smell, you take a smaller sniff than if you inhaled and didn’t detect a smell,” Frank explains. “For someone with normal sense of smell, the size of the sniff when detecting an odor is cut in half. For someone who cannot detect odor, the size of the sniff for just air and the size of the sniff for an odor are the same.”
In humans, Frank says the sense of smell is one of our less robust senses. He says it’s more susceptible to harm because there is less neurological machinery in the brain devoted to processing the sense of smell. “So, that’s the reason it might be acting a little bit like the canary in the mineshaft. Because it’s more fragile, when you have insult to the brain, it may be sensitive to loss earlier in the disease process.”
Frank adds that because smells don’t have to be identified as part of the Sniff Magnitude Test, the test can be used on adults as well as children (who may be too young to link a smell with a name) and people representing international cultures (who are unfamiliar with some common odors in the U.S.). “What’s also unique about this test is that it does not require a good memory, which is an issue in testing people with Alzheimer’s or some other dementia-related disease,” Frank says. “For instance, other tests ask, ‘Does this smell like garlic?’ or, ‘Does this smell like tar, or roses?’ Once there’s a problem with memory, this kind of test would be difficult.”
So what does it mean if a child, or someone unlikely to have an age-related disease, flunks the sniff test? “If they fail our test, that’s a pretty good indication that there’s something wrong with their sense of smell. Maybe there’s an obstruction – a deviated septum or polyps,” Frank says. “Perhaps the olfactory nerve has been damaged due to a head injury or a viral infection.”
For those who are proud of their keen sense of smell, this is not a test to tickle their senses. Because the really nasty smells worked best for the Sniff Magnitude Test, Frank says the test subjects get a whiff of three odors: a blend of ripe cheese and rancid meat, a fragrance that combines a burning smell with a skunk-like smell, and amyl acetate, which smells like banana. “You have to get people to really suppress the sniff and that’s why the bad odors work so well,” explains Frank. “To a certain extent, we put the banana smell in there to give them a little break.”