Prevalence and correlated factors of REM sleep behavior disorder in patients with progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a rapidly advancing tauopathy, and amongst rapid eye movement (REM) sleep behavior disorder (RBD) has been observed. Prior studies were limited by small samples and inconsistent results; meanwhile, research is lacking since the updated criteria for PSP. This cross-sectional study aimed to assess RBD in a sizable PSP cohort.

Participants were consecutively recruited from the movement disorders specialty at West China Hospital between January 2019 and January 2021, adhering to established inclusion and exclusion criteria. We collected and analyzed clinical characteristics, scale assessments, and polysomnographic data to determine the prevalence and correlated factors of RBD in patients with PSP.

The initial cohort comprised 153 PSP patients, with a median age of 68 years and 61.4 % male. Possible RBD (pRBD) was identified in 43 individuals (28.1 %; assessed by scale), who experienced more constipation, hyposmia, fatigue, drank less, and showed poorer cognition. Multivariate analysis indicated an inverse relationship between alcohol intake and pRBD, whereas constipation was positively linked to pRBD. Eighty-six PSP patients and 24 matched controls underwent polysomnography. Patients with PSP displayed more sleep disruption. Among them, 24 (27.9 %) were eventually diagnosed with RBD. No significant differences in sleep parameters, except for REM sleep without atonia, were found between the RBD and non-RBD groups. Patients with RBD reported increased constipation, fatigue, and overall non-motor symptoms. Similarly, constipation was positively associated with RBD.

Approximately 28 % of PSP patients have comorbid RBD, which correlates with various non-motor symptoms, particularly constipation. Further research is needed to elucidate the interaction of these disorders.