Brain slow waves and memory in healthy aging and early Alzheimer's

With age, memory processes (encoding, consolidation and retrieval) as well as daytime vigilance are altered. Sleep is also impaired in older adults, notably slow waves that are known to play a key role in memory consolidation. Interestingly, some slow waves can also be detected in EEG recordings during wakefulness, and have been related to vigilance fluctuations.

The investigators believe that slow waves, during both sleep and wakefulness, could constitute a common biomarker of sleep disturbances and daytime vigilance problems. A dysregulation of slow waves could thus explain the impact of aging on the different memory processes. Since alterations in memory capacity, attention, and sleep quality are further exacerbated in patients with Alzheimer's disease (AD), the investigators propose to study the links between aging (normal and pathological), sleep and daytime vigilance alterations, and their impacts on the different key stages of memory.

The investigators will examine the associations between slow waves and changes in memory and vigilance in normal and pathological aging by studying young adults, seniors without cognitive disorders, and patients with prodromal AD. By replaying sensory cues associated with learning material during sleep, the investigators will also evaluate the effectiveness of auditory stimulation during sleep to enhance memory consolidation in older adults without and without cognitive deficits.

Overall, this study aims to better understand the relationships between slow waves, aging, memory, and vigilance, providing insights into cognitive decline and potential interventions in aging and Alzheimer's disease.