Sleep Disorders and Dementia: From Basic Mechanisms to Clinical Decisions

Abstract

A growing body of evidence shows the bidirectional relationship between sleep disorders and dementia. Sleep disorders often precede cognitive impairment by many years, in keeping with evidence that certain degenerative diseases originate from the brainstem and hypothalamus. Such selective vulnerability is associated with sleep fragmentation, daytime napping, sleep phase disorders, insufficient or excessive sleep duration, and sleep-disordered breathing. However, recent research indicates that sleep disorders accentuate neuropathology, such as decreased slow-wave sleep (SWS) promoting amyloid aggregation. This bidirectional relationship makes for a self-promoting feedback loop that accelerates both processes, highlighting the need for early interventions in elderly patients without dementia. Behavioral interventions, such as sleep hygiene, daytime exercise, and avoidance of alcohol and coffee after a certain time of day, are important first steps. Equally important are interventions that promote sleep consolidation, enhance SWS, or correct sleep-disordered breathing. Finally, optimizing medication timing, such as daytime-only use of cholinesterase inhibitors, can improve sleep and memory consolidation. [ Psychiatr Ann . 2017;47(5):227–238.]