Sleep behaviors change with advancing age with older individuals experiencing sleep disturbances, such as alterations in sleep cycles, sleep duration and sleep fragmentation. Such disturbances have been linked to cognitive decline in older populations. Some researchers argue that sleep disturbances are a consequence of neurodegeneration, while others posit that sleep disturbances predate progressive brain degeneration. The aim of the present narrative review was to present what is known pertaining to the sleep-cognitive decline linkage and discuss major methodological limitations in the relevant research. Specifically, the lack of longitudinal studies with long follow-up timeframes, along with lack of consensus regarding the research tools used for assessing sleep and cognitive state, limit the ability to disentangle the relationship between sleep disturbances and cognitive decline. In conclusion, sleep may be a modifiable risk factor, thus, timely and sleep-specific interventions could help counteract the adverse effects of potential neurodegeneration.
Koutsimani et al. (Fri,) studied this question.