Grant: CIHR Fellowship

Alzheimer's disease (AD) dementia syndrome is now recognized as a late-stage of the disease, but its harmful effects start much earlier, with brain changes occurring 15-20 years before noticeable symptoms like memory deficits or mild cognitive impairment (MCI) appear. Detecting these early changes typically requires costly and/or invasive techniques such as brain scans or spinal taps, making widespread screening costly and impractical. Research has shown that early in AD, the neural circuits responsible for smell, particularly the olfactory bulb and the entorhinal cortex, are damaged by AD. This damage can cause a decline in the sense of smell, which is often one of the earliest signs of AD, even before significant memory issues arise. To address this, we developed a simple, non-invasive smell test that can be taken at home. This test aims to identify individuals at risk of AD and monitor disease progression in those who are currently cognitively normal. Early trials of the test have been promising, showing a distinction between individuals with memory deficits and those without cognitive issues. Objectives: (1) To determine if a person's sense of smell is associated to biomarkers associated with AD in those at risk. (2) To assess whether poor performance on the smell test can predict significant cognitive decline within two years. We will test the sense of smell in 325 participants from various research centers and collect detailed biomarker data from 150 participants to support our findings. The smell test will be administered remotely via Zoom Healthcare. We will analyze the relationship between smell test performance and AD biomarkers, as well as future cognitive health. Our results will support the use of the AROMHA Brain Health Smell Test as a practical at-home screening tool for AD, potentially alongside other digital biomarkers. With new AD treatments on the horizon, an accessible and non-invasive screening method is crucial for early intervention.