Research Progress on the Relationship between Parkinson's Disease and REM Sleep Behavior Disorder.

An individual's quality of life is greatly affected by Parkinson's disease (PD), a prevalent neurological degenerative condition. Rapid eye movement (REM) sleep behavior disorder (RBD) is a prominent non-motor symptom commonly associated with PD. Previous studies have shown a close relationship between PD and RBD. In addition to being a prodromal symptom of PD, RBD has a major negative impact on the prognosis of PD patients. This intrinsic connection indicates that there is a bidirectional relationship between PD and RBD. This paper provides a comprehensive review of the pathological mechanism related to PD and RBD, including the α-synuclein pathological deposition, abnormal iron metabolism, neuroinflammation, glymphatic system dysfunction and dysbiosis of the gut microbiota. Increasing evidence has shown that RBD patients have the same pathogenic mechanisms that underlie PD, but relatively little research has been done on how RBD contributes to PD progression. Therefore, a more thorough investigation is warranted to characterise how RBD affects the course of PD, in order to prepare for future therapeutic trials.