Project 458456

The diagnosis of Alzheimer's disease is currently made when the criteria for dementia are met, i.e. when the cognitive deficits are severe enough to interfere with the person's autonomy. Thus, it is important to find early markers of the disease in order to be able to intervene before the dementia stage, for example, at the subjective cognitive decline stage. This stage is characterized by complaints of cognitive decline with a level of neuropsychological performance remaining within normal range. This marker is sensitive, but not very specific. The sense of smell could specify its predictive value. Olfactory impairment is present in the mild cognitive impairment stage, a stage between subjective cognitive decline and Alzheimer's disease. However, no studies have evaluated the olfactory system, as well as its specific neurological damages, within subjective cognitive decline. Using a longitudinal design, combining olfactory and magnetic resonance imaging (MRI) measurements, the objective of the study is to evaluate the olfactory system of people with subjective cognitive decline compared to a healthy elderly group. In addition, the project aims to study the possible associations between grey matter atrophy and cognitive/olfactory decline of this population. Ultimately, the identification of affected brain regions in subjective cognitive decline will allow us to better predict who is at risk of developing Alzheimer's disease. The results of this project will identify specific patterns of cerebral, olfactory, and cognitive changes that are the best predictors of the early stages of Alzheimer's disease. This research has the potential to provide a new approach for early detection of individuals at high risk to develop Alzheimer's Disease.