[Olfaction and Alzheimer's disease: from deficits to therapeutic hopes].

Abstract

Odors are known to entertain a special link with memory: once the meaning of an odor has been learned, it naturally acts as a retrieval cue of the learning context, along with the emotions and behaviors associated with it. The existence of this link has for several years inspired the study of olfactory function in Alzheimer's disease (AD), known for the memory disorders it causes. The aim of this review is to summarize the current scientific knowledge on the almost paradoxical dual role played by odors in the management of AD, as both screening and therapeutic tools. In fact, while the existence of a specific olfactory deficit is confirmed in AD - as is its ability to screen for the disease - its properties do not prevent from taking advantage of the link between odors and memory to stimulate cognition and behavior in these patients. Current scientific data, albeit limited and with sometimes inconsistent results, suggest that this idea seems relevant. However, interventions based on impaired processing in AD, such as the recognition and naming of olfactory stimuli, must be avoided.