Altered Biological Rhythm and Alzheimer's Disease: A Bidirectional Relationship.

Biological rhythms have become the research focus in recent years. Biological rhythm disruption is a common symptom of Alzheimer's disease (AD) patients, which is usually considered as the late consequence of AD. Recent studies have shown that biological rhythm disruption even occurs before the onset of clinical symptoms of AD. The causal relationship between AD and biological rhythm disruption is not clear. Delineating their relationship can help understand the disease mechanisms and make the early diagnosis of AD possible. This review integrates the research on the abnormal changes of the biological rhythm-related parameters in the clinical manifestations of AD patients and the roles of the biological rhythm disorders in AD. We will discuss the links between biological rhythms and AD, with the focus on the bidirectionality between biological rhythms and AD processes. Collectively, these updated research findings may provide the basis for further exploring the significance of rhythm in the diagnosis and treatment of AD.