Diagnosing Alzheimer's: A Peanut Butter Sniff Test?

Contributed by: Dennis Fortier, President, Medical Care Corporation

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You cannot accurately diagnose Alzheimer's disease with a smell test. The prospect of doing so makes for tantalizing headlines, but the science does not stand up.

To be fair, the prospect of diagnosing Alzheimer's Disease with a sniff test, including this latest flurry of news based on a peanut butter study at the University of Florida, has a legitimate, scientific underpinning. In fact, many Alzheimer's patients do indeed suffer from impaired smell sensitivity.

However, trying to diagnose Alzheimer's disease based on such a test has two major limitations.

First, many medical conditions cause impaired smell sensitivity, including allergies and normal aging, both of which are far more common than Alzheimer's Disease. So loss of smell sensitivity is certainly not a reliable indicator of Alzheimer's disease.

Second, many Alzheimer's patients retain a sharp sense of smell for many years, so intact olfactory function does not mean that one does not have Alzheimer's Disease.

Stories about smell tests, and their utility as Alzheimer's diagnostics, often get a lot of press. In fact, many experts agree that such stories get more coverage than scientifically merited. It is clear that optimistic stories about medical advances attract an audience, and are therefore interesting to news publishers, but you should read them with full awareness and appropriate expectations.

A peanut butter smell test for Alzheimer's diagnosis is not in our future.