At-Home Smell Test for Cognitive Impairment Promising

Researchers have developed and validated a simple “peel-and-sniff” test that can be completed unsupervised at home to screen for cognitive impairment.

It’s well known that impaired olfactory function is often associated with cognitive decline and may serve as an early indicator of neurodegenerative diseases like Alzheimer’s disease, prompting interest in developing smell-based screening tests.

The AROMHA Brain Health test (ABHT) — in which participants sniff odor labels that have been placed on a card — assesses an individual’s ability to discriminate, identify, and remember odors.

In testing, adults with mild cognitive impairment (MCI) scored lower on the test than adults with normal cognitive function.

“When combined with other digital biomarkers, a mobile self-administrated and diverse smell assessment like ours could accelerate screening for neurodegenerative diseases in asymptomatic or newly symptomatic individuals who would benefit from more definitive subsequent tests, such as blood-based, image-based, or cerebrospinal fluid (CSF)–based diagnostics, especially in individuals presenting additional risk factors for dementia such as subjective cognitive decline, depression, and genetic risks factors such as the APOE-4 allele,” the investigators wrote.

The study was published online on March 24 in Scientific Reports.

Sense of Smell Declines With Age

The ABHT was developed by a team led by Mark Albers, MD, PhD, in the Laboratory of Olfactory Neurotranslation, McCance Center for Brain Health, and Department of Neurology at Massachusetts General Hospital, both in Boston.

The study included 127 cognitively normal adults, 34 with subjective cognitive complaints, and 19 with MCI who took the test at home, under both unobserved and observed conditions.

Overall, test results were similar across English- and Spanish-speaking participants, and participants performed the test equally successfully regardless of whether they were observed or not, the researchers reported.

As expected, the researchers found that odor identification, memory, and discrimination declined with age.

They also found that adults with MCI had lower scores for odor discrimination and identification than older adults who were cognitively normal or had subjective cognitive complaints, independent of age, sex, and education.

“Early detection of cognitive impairment could help us identify people who are at risk of Alzheimer’s disease and intervene years before memory symptoms begin,” Albers said in a news release.

Looking ahead, the researchers said future studies could incorporate neuropsychological testing and could follow patients over time to see if this test can predict cognitive decline.

Last year, a team from Columbia University in New York city reported that combining a brief smell test with a short memory exam can predict cognitive decline as accurately as costly brain imaging, offering a more affordable and accessible way to assess risk for Alzheimer’s disease and other forms of dementia.

The research received funding from the National Institutes of Health. Albers is a co-founder and owns shares in Aromha Inc., a company developing scent-based screens for neurodegenerative disorders and COVID-19.