An at-home smell test may be on the horizon to detect early Alzheimer's. (Alona Siniehina/Shutterstock)
In a nutshell
A simple at-home smell test, the AROMHA test, could help detect early signs of Alzheimer’s disease years before memory loss symptoms appear, offering a non-invasive and cost-effective screening tool.
The brain regions responsible for processing smells are among the first affected by Alzheimer’s, making olfactory performance a potential early biomarker for cognitive decline, with the test revealing differences between normal aging, mild cognitive impairment, and Alzheimer’s.
The test’s remote, self-administered design allows for easy use at home, making it a promising option for reaching underserved populations and enhancing early detection, even for people in remote or underserved areas.
BOSTON — Something as simple as smelling a scratch-and-sniff card might help doctors spot Alzheimer’s disease years before memory problems begin. New research from Massachusetts General Hospital shows that how well we identify and remember different odors could warn us about cognitive decline.
The study, published in Scientific Reports, introduces a smell test called AROMHA that people can take at home. This breakthrough tackles a big problem in medicine: finding cheap, non-invasive ways to detect Alzheimer’s before obvious symptoms show up.
Why Smell Matters for Brain Health
The brain areas that process smells are among the first hit by Alzheimer’s disease. The damaging protein clumps that characterize Alzheimer’s start building up in smell-processing regions very early on.
These brain circuits develop Alzheimer’s disease changes before symptoms start. These changes can begin 15-20 years before memory problems appear, giving doctors a potential early warning window.
The olfactory sensory nerve pathway for smell detection. (JitendraJadhav/Shutterstock)
The AROMHA test is pretty straightforward. Participants receive cards in the mail with smell-infused labels. They peel and sniff these labels while following instructions on a website. The test checks several smell abilities: naming odors correctly, telling different smells apart, remembering smells from earlier in the test, and rating how strong each smell seems.
For their study, the researchers tested 127 people with normal cognition, 34 people who worried about their memory but tested normally, and 19 people with mild cognitive impairment (MCI), which often precedes Alzheimer’s. They also included seven patients diagnosed with an inability to smell as a comparison group.
Beyond Normal Aging: What They Found
People with mild cognitive impairment performed much worse on smell identification and discrimination tests compared to others. As expected, people with diagnosed smell loss scored at levels suggesting they were just guessing, confirming the test was actually measuring smell ability.
One practical finding was that the test worked equally well whether participants did it with a researcher watching remotely, in person, or completely on their own. It also performed similarly in both English and Spanish.
Age patterns showed up too. Among people with normal cognition, smell abilities declined with age, which is expected. But the decline was much steeper in people with mild cognitive impairment, showing that something beyond normal aging was happening.
Most participants over 55 completed the test successfully at home, challenging the idea that older adults struggle with self-administered digital tests. The test also had a smart “confidence” component. After identifying each smell, participants rated how sure they felt about their answer. This awareness aspect could provide extra insights, as how aware we are of our own mental state has been linked to brain disease progression.
How This Could Change Doctor Visits
This could provide earlier detection, allowing patients to receive treatment before extensive brain damage develops. (© Mikki Orso – stock.adobe.com)
Currently, many patients only seek help after noticing memory problems. By then, significant brain damage has already occurred. Earlier detection could identify people who might benefit from new treatments or clinical trials.
Doctors have known for decades that smell loss can signal brain diseases. What’s special about this test is how practical it is. A smell test could become part of your regular check-ups after 55, potentially flagging those who need more thorough testing.
Different smell problems might even help doctors tell different conditions apart. Alzheimer’s mainly affects smell identification, while Parkinson’s causes more general smell problems. Other conditions affecting smell include Lewy body dementia, frontotemporal dementia, and brain injuries.
Because people can take the test at home, it could reach underserved communities and people in remote areas who can’t easily see specialists. This could make early detection of brain diseases more accessible to everyone. Our noses, it turns out, might detect brain problems long before our memories fail us.
Paper Summary
Methodology
The AROMHA test uses scratch-and-sniff technology on five cards with smell-infused labels. Participants access a website that guides them through the testing process. The test has three main parts: First, an identification test where participants smell nine odors (including menthol, clove, and strawberry), rate their intensity, and identify them from multiple choices. After a short break, they complete a memory test with the original nine odors plus nine new ones, identifying which they smelled before. Finally, they do a discrimination test determining whether pairs of smells are the same or different. Participants could complete the test with a researcher observing via Zoom, in person, or entirely independently. The whole test takes about 30-40 minutes.
Results
The study found that people with mild cognitive impairment performed significantly worse on smell identification and discrimination tests compared to both healthy individuals and those with only subjective memory concerns. These differences remained even after accounting for age, sex, and education. The test worked equally well in both English and Spanish, and performance was consistent whether participants were observed or unobserved during testing. Among cognitively normal people, smell abilities naturally declined with age, but this decline was much steeper in those with cognitive impairment. Participants with diagnosed smell loss scored at chance levels, validating the test’s accuracy.
Limitations
The study had several limitations. Not all participants underwent comprehensive cognitive testing—some were “verified” through neuropsychological assessment while others self-reported their cognitive status. The study also compared different groups at one point in time rather than tracking individuals over years, which would better show how smell changes might predict cognitive decline. The sample size was relatively small, particularly for people with mild cognitive impairment (only 19 participants). Finally, while the test showed strong connections to cognitive status, future studies will need to connect test performance with biological markers of Alzheimer’s disease.
Discussion and Takeaways
The AROMHA test represents a promising screening tool that could help identify people at risk for cognitive decline before memory symptoms become obvious. Its self-administered, remote format makes it accessible to diverse populations, including older adults who might not be tech-savvy. Different patterns of smell problems might help distinguish between various brain diseases—Alzheimer’s primarily affects smell identification, while Parkinson’s causes broader smell impairment. The test could serve as an inexpensive first step to identify people who might benefit from more intensive diagnostic procedures like blood tests or brain imaging, particularly as new treatments emerge that work best early in the disease process.
Funding and Disclosures
The study was funded by the National Institutes of Health. Two of the authors are co-founders and shareholders in AROMHA Inc., the company developing the test, while two others serve as consultants for the company. One author reported additional consulting relationships with other companies and acknowledged receiving donations from International Flavors and Fragrances and Eli Lilly. These potential conflicts of interest were reviewed by the Massachusetts General Hospital Office of Industrial Interactions.
Publication Information
The study, titled “The AROMHA brain health test is a remote olfactory assessment to screen for cognitive impairment,” was published in Scientific Reports (Volume 15, Article 9290) in 2025. The research was led by Mark Albers, Benoît Jobin, and colleagues from Massachusetts General Hospital, Harvard Medical School, Université du Québec à Trois-Rivières, AROMHA Inc., and Endicott College. The article is available under a Creative Commons license allowing non-commercial use and sharing with proper attribution.