Loss of smell linked to early dementia symptoms


Anosmia, or the loss of smell, can be an early sign of Alzheimer’s-related complications, according to a new study that focused on observations of older, healthy adults. The loss of smell could also indicate the accumulation of proteins, such as amyloid-beta and tau, which can be considered biomarkers of dementia-related disease.

Researchers surmise that the decline of someone’s sense of smell is linked to an accelerated buildup of disease-related clues that are visible in brain scans. The findings were compiled by the National Institute on Aging and published in the Journal of Alzheimer’s Disease.

While the loss of a sense of smell has been previously linked to early warning signs, the connection between anosmia and specific biomarkers is new territory.

To conduct the study, the team of researchers tracked about 400 patients for about two and half years. Healthy participants without any initial signs of cognitive decline underwent PET scans, which can detect harmful proteins associated with the deteriorating disease. They also took odor identification tests.

Over time, about five percent of individuals in the study began to develop mild cognitive impairment, some of which were linked to Alzheimer’s and other dementia-related illnesses.

Researchers found that people who had more difficulty identifying certain scents in tests were about 22 percent more likely to develop some form of cognitive decline. Even as scientists accounted for other factors, such as age, overall health and depressive symptoms, the relationship between the loss of smell and a higher probability of developing cognitive impairment remained unchanged.

The PET scans of some subsets of the group confirmed that lower olfactory scores are linked to higher levels of disease pathology in areas of the brain responsible for smell, memory and learning. They also had elevated levels of amyloid-beta and tau, which are also related to smell and memory function.

The takeaway here is that there’s growing evidence that loss of olfactory functions can indicate the progression of neuropathological damage associated with Alzheimer’s.

Scientists plan to expand this line of research and hope to uncover any other possible links between loss of smell and dementia-related complications.

As studies continue to come out that help shed light on Alzheimer’s, it is important that we all continue to focus on being dementia aware. If you would like more information, contact me today!

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