Is Sense of Smell an Early Indicator of Alzheimer’s?

Sense of smell can let you know when it’s time to take your dinner out of the oven, it can help pick out a new candle, and it can remind you what season it is. But a new study suggests that your sense of smell may be able to do a lot more than that: It could detect the early signs of Alzheimer’s disease.

According to a recent study by Dr. Mark Albers, a researcher at Massachusetts General Hospital and an assistant professor of neurology at Harvard Medical School, the decline in olfaction, or sense of smell, may be an early indicator of Alzheimer’s disease. Albers says in a report that this deterioration may occur 10 to 20 years before the cognitive effects of the disease show up. If researchers can identify Alzheimer’s before any cognitive effects occur, then new work on Alzheimer’s prevention can greatly improve.

To help discover early traces of the disease, Albers created noninvasive smell tests that relate to a person’s ability to recall, name, and associate. In one of the tests, patients get four options to identify an odor. Normally people will do well on this test, but those with mild cognitive impairment, a condition that increases your risk of Alzheimer’s, do not.

According to the report:

“Olfaction may be particularly sensitive to Alzheimer’s Disease,” Dr. Albers says, since it involves two different regions of early AD pathology: the olfactory bulb, which is the first way station for olfactory information in the brain, and the entorhinal cortex, which receives input from the olfactory bulb and is a gateway to the hippocampus, the seat of episodic memory.

If the connection between a deteriorating sense of smell and Alzheimer’s is confirmed, then Albers’ three part test could be used as a non-invasive and cost effective way to detect early signs of the disease in most adults over the age of 50.