The effect of REM sleep behaviour disorder on clinical severity in Parkinson's disease

Abstract

Aim: Differently from previous studies that directly compared Parkinson's disease (PD) patients with and without rapid eye movement (REM) sleep behavioural disorder (RBD) for the stage, severity, and duration of disease, this study investigated the relationship between the duration and clinical severity of disease in PD patients with and without RBD. Materials and methods: This retrospective study consisted of 141 PD patients older than 18 years of age. The clinical diagnosis of RBD was based on the minimal diagnostic criteria of the revised 2001 International Classification of Sleep Disorders. The patients were divided into 2 subgroups, those with and without clinical RBD. The groups were then compared with each other for sex, age, the duration of disease, and the Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale scores. The correlation between the duration of disease and the clinical severity of PD was analysed in all patients. Results: There was no significant difference between the groups in terms of sex, age, disease duration, and clinical severity scores. For the RBD patients there was a weak positive correlation between the duration of PD and clinical severity scores. However, there was no such correlation in the non-RBD (NRBD) subgroup. Conclusion: Our study indicates that in PD patients with RED compared with NRBD patients, the time taken to reach the same clinical severity scores may be shorter.