Grant: Master's Award: Canada Graduate Scholarships

Alzheimer's disease (AD) diagnosis is only made very late, at the stage of dementia, where cognitive disorders resonate in the activities of daily living. Faced with this situation, the category of Mild Cognitive Impairment (MCI) has been introduced to characterize people at risk of developing AD. Even further upstream, Subjective Cognitive Decline (SCD) is characterized by the presence of non-objectified cognitive complaints. However, although SCD constitutes a sensitive marker for the development of AD, it is not very specific. In order to use it as an early marker of AD, one could combine it with smell tests. Indeed, altered olfactory abilities have been demonstrated in MCI and more recently in SCD. A few recent studies report abnormal brain activity patterns in patients with AD using olfactory evoked potentials (OEP). Thus, this project aims to assess the olfactory functions of individuals with an SCD and to compare them with those of a control group using behavioral and electrophysiological measures. We hypothesize that (1) individuals with SCD have lower behavioral olfactory scores than controls; (2) individuals with SCD have longer OEP latencies and smaller OEP amplitudes than controls; (3) behavioral olfactory tests scores and OEP latencies/amplitudes are correlated. To test these hypotheses, 80 individuals with SCD and 80 control participants matched by gender and age will be recruited and invited to the laboratory for evaluation. We will test olfaction (1) by behavioral and (2) electrophysiological measurements. Other measures assessing cognition will complement this assessment. This research will allow the development of new tools for early detection of AD and will help to initiate rapid action before the onset of cognitive symptoms.