“Canary in the Coal Mine” Test Sniffs Out Brain Issues Early

By Dr. Scott Olson, ND Posted June 25, 2025

One of the most common questions I get is how to tell if you’re starting to experience cognitive decline.

I get it—losing your memory is scary, especially when it sneaks up on you.

But here’s some exciting news that might put your mind at ease. A fascinating new study suggests that your nose might be the early warning system we’ve been looking for all along.

Researchers from Harvard-affiliated Massachusetts General Hospital have developed a simple smell test that could revolutionize how we detect cognitive decline—right from our own living rooms.

As it turns out, your nose knows—often well before your brain shows obvious symptoms.

This groundbreaking research, published in Scientific Reports, found that older adults with mild cognitive issues performed significantly worse on odor identification and memory tasks compared to those with normal cognitive function.

What makes this finding so exciting is its  simplicity and accessibility.

The AROMHA Brain Health Test works by having participants scratch and sniff odor labels placed on cards. Then, a web-based app is used to assess their ability to identify, distinguish, and remember different smells.

No fancy equipment, no expensive brain scans, no invasive procedures—just a simple sniff test that can be completed at home.

Why does this work?

It turns out that problems with smelling (what scientists call olfactory dysfunction) can serve as an early warning sign for neurodegenerative diseases such as Alzheimer’s, Parkinson’s, chronic traumatic encephalopathy, and traumatic brain injury.

Think of your sense of smell as the “canary in the coal mine.” for your brain health. Your ability to smell often deteriorates before other more noticeable cognitive symptoms appear, giving you a head start on detection and intervention.

The potential impact of this research is substantial:

Early detection: Spotting cognitive decline years before more obvious symptoms appear allows for earlier intervention when treatments may be more effective.

Accessibility: A simple, affordable test that doesn’t require a trip to a specialist could make screening available to many more people.

Widespread screening: This test could be used in primary care settings, community health centers, or even at home, reaching people who may otherwise be overlooked.

While this specific test isn’t widely available to the public yet, it’s certainly something to look for in the near future. The researchers are continuing their work to validate the test in larger populations.

In the meantime, if you notice changes in your sense of smell that aren’t related to a cold or sinus issue, it’s worth mentioning to your doctor. While smell loss can occur for many reasons—and often has benign explanations—it could potentially be an early sign worth investigating, especially if you have other risk factors for cognitive decline.

P.S. You may also qualify for a free scratch and sniff test as part of a research study on smell loss and brain disease being conducted by the Michael J Fox Foundation for Parkinson’s Research. Go to MySmellTest.org for more information.

Source:

Jobin, B., Magdamo, C., Delphus, D. et al. The AROMHA brain health test is a remote olfactory assessment to screen for cognitive impairment. Sci Rep 15, 9290 (2025). https://doi.org/10.1038/s41598-025-92826-8

Written By Dr. Scott Olson, ND

Nearly 25 years ago, failed mainstream medical treatments left Dr. Olson in constant pain – and his health in ruins. And that’s when he did something REVOLUTIONARY. He began his career in medicine – and dedicated his life to uncovering the true, underlying causes of disease.
Through his innovative medical practices in Tennessee and Colorado, Dr. Olson has helped cure countless seniors from across America of arthritis… heart disease… diabetes… and even cancer. All without risky prescription drugs or painful surgeries.

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