New Test Can ‘Sniff’ Out Early Signs of Alzheimer’s

A new test hopes to sniff out early signs of Alzheimer’s — literally.

A person’s sense of smell is known to decline in the early stages of Alzheimer’s. Scientists believe that this drop in sense of smell is due to memory-impairing changes to the brain.

According to a new study from the University of Pennsylvania School of Medicine, researchers believe that determining how well the olfactory system is working can help in early diagnosis of dementia.

“There’s the exciting possibility here that a decline in the sense of smell can be used to identify people at risk years before they develop dementia,” said principal investigator David R. Roalf, PhD, an assistant professor in the department of Psychiatry at Penn.

The study evaluated 728 elderly people using a standard cognitive assessment test as well as Sniffin’ Sticks, an identification test using 16 everyday smells. The volunteers were categorized as “healthy older adults,” “mild cognitive impairment” or “Alzheimer’s dementia.”

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Using only the cognitive test, the researchers were able to correctly identify 75 percent of the group with a pre-dementia condition that leads to Alzheimer’s called mild cognitive impairment (MCI). After adding the sniff test, the results went up to 87 percent. Their findings were published in the Journal of Alzheimer’s Disease.

“These results suggest that a simple odor identification test can be a useful supplementary tool for clinically categorizing MCI and Alzheimer’s, and even for identifying people who are at the highest risk of worsening,” Roalf said.

Previous studies have linked a weakening sense of smell to Alzheimer’s, yet only a few larger dementia clinics have begun to use the smell tests to help diagnose elderly patients. Smell tests are not yet common because many take too long to administer. Roalf and his team hope to next develop shorter tests that will work as well as the longer ones.

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“We’re hoping to shorten the Sniffin’ Sticks test, which normally takes 5 to 8 minutes, down to 3 minutes or so, and validate that shorter test’s usefulness in diagnosing MCI and dementia — We think that will encourage more neurology clinics to do this type of screening,” Roalf said.