Can a Smell Test Predict Your Risk for Alzheimer’s?

A series of simple odor tests may point to early signs of Alzheimer's

elderly coupleThis article originally appeared on Live in the Now.

One of the problems with predicting your chances of developing Alzheimer’s disease is that there is no actual medical test for it. It’s generally diagnosed when the signs of it start rearing their ugly head, like confusion, memory problems and an inability to follow a conversation.

So wouldn’t it be great if there was some sort of early-warning system in place that could identify your risk well ahead of time?

Well, there might be a surprising way to do just that.

It turns out that a series of simple odor tests may point to early signs of Alzheimer’s.

In a new study, researchers tested 183 people to see if they could identify 10 common odors in a test called OPID-10 (Odor Percept IDentification). These included menthol, clove, leather, strawberry, lilac, pineapple, smoke, soap, grape or lemon. After two seconds of exposure to each aroma, participants had to choose a word to describe the odor. Next, participants took a 20-item (OPID-20) test. It included all of the odors above along with 10 more: banana, garlic, cherry, baby powder, grass, fruit punch, peach, chocolate, dirt and orange.

In this case, the subjects first had to identify if an odor was included in the previous test. This determined their Percepts of Odor Episodic Memory (POEM) score. Then they were again asked which word best described each odor. Finally, participants sniffed two consecutive odors and had to identify if they were the same or not.

What Were the Results?

People with poor scores on the OPID-20 test showed thinning of two brain regions — the hippocampus and the entorhinal cortex. Thinning in these areas is associated with Alzheimer’s risk. The OPID-20 test also picked out people who didn’t have any signs of Alzheimer’s, but carried gene variants connected with the disease. Additionally, the ability to remember a previous odor was quite different between people with normal cognitive function and those with Alzheimer’s disease.

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Don’t Panic if You’re Bad at Detecting Odors

If you have problems detecting odors it’s something you probably want to have checked out by your doctor. But don’t panic! Sense of smell varies greatly from person to person. It also declines with age. Plus, problems like chronic sinusitis can alter your ability to identify odors.

Still, the fact remains that loss of olfactory abilities remains strongly linked to the development of Alzheimer’s.

“There is increasing evidence that the neurodegeneration behind Alzheimer’s disease starts at least 10 years before the onset of memory symptoms,” says Mark Albers, MD, PhD, the principal investigator of the report. This means that non-invasive ways to test for Alzheimer’s — like odor detection tests — may be very important when it comes to slowing down and treating progression of the disease.

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Ability to Recognize and Recall Odors may Identify Those at Risk for Alzheimer’s Disease. Press Release. Massachusetts General Hospital. Nov 2016.

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