Dysfunction of circadian and sleep rhythms in the early stages of Alzheimer's disease

Abstract

Dysfunction of circadian and sleep rhythms is an early feature of many neurodegenerative diseases. Alzheimer's disease (AD) is a progressive neurodegenerative disorder resulting in cognitive and psychiatric disturbances. Although it is largely unclear whether dysfunctions in sleep and circadian rhythms contribute to the etiology of AD or are a consequence of the disease, there is evidence that these conditions are involved in a complex self‐reinforcing bidirectional relationship. According to the recent studies, dysregulation of the circadian clock already occurs during the asymptomatic stage of the disease and could promote neurodegeneration. Thus, restoration of sleep and circadian rhythms in preclinical AD may represent an opportunity for early intervention to slow the disease course.

The Bidirectional Relationship between Sleep and Neurodegeneration: Actionability to Improve Brain Health

“…In the early stages of Alzheimer's disease, sleep is already affected: melatonin release is dysregulated, sleep apnea and naps are frequent, sleep macroarchitecture is affected with sleep fragmentation, reduced sleep efficiency, and REM sleep dysregulation, and on the microarchitectural level, K-complexes are altered [41].…”

Color in physiology

“…Recent insights into visual perception and signal interpretation include for example the role of pacsin proteins in vision, a novel function of these regulators of the actin cytoskeleton and cellular transport processes. 7 Also, in the context of visual perception and the role of visual stimuli in maintaining healthy circadian rhythms, the influence of an impaired eyesight 8 and the role of the eye as not only a light-but also temperaturesensitive organ 9,10 have been described.…”

Aryl hydrocarbon receptor impairs circadian regulation in Alzheimer's disease: Potential impact on glymphatic system dysfunction

“…There is clear evidence that circadian rhythms are impaired in AD patients (Chauhan et al, 2017;Homolak et al, 2018;Hoyt & Obrietan, 2022;Rigat et al, 2023). Currently, there is a debate whether the disturbances of the circadian clocks are a cause or a consequence of AD pathology.…”