Clinical REM sleep behavior disorder and motor subtypes in Parkinson's disease: a questionnaire-based study.

Abstract Objectives Studies documenting the association between rapid eye movement sleep behavior disorder (RBD) and motor subtypes in Parkinson's disease (PD) are rare. Our hypothesis is that RBD may be more severe in non-tremor dominant (NTD) patients with RBD than those tremor dominant (TD) with RBD. In this study, we investigated the association between motor subtypes and clinical RBD in PD. Patients and methods We evaluated 104 consecutive patients older than 18 years presenting with PD to the Neurology Clinic of the University Hospital for one year in this study. The clinical diagnosis of RBD was based on the minimal diagnostic criteria of International Classification of Sleep Disorders, revised. The Stavanger Sleepiness Questionnaire was used to rate the severity of clinical RBD. The patients were divided into two subgroups as TD and NTD. The patient and control groups were compared with each other for severity and frequency of clinical RBD, and the Unified Parkinson's Disease Rating Scale (UPDRS) and Hoehn–Yahr stage scores. The correlation between severity of clinical RBD and clinical severity of PD was analyzed in the patient groups. Results Of the patients, 45.2% ( n =47) had the NTD subtype of PD and 54.8% ( n =57) had the TD subtype of PD. There was no significant difference among the groups in terms of frequency and severity of clinical RBD. For the NTD patients, there was a weak positive correlation between severity of clinical RBD and clinical severity of PD. However, there was no correlation in the TD subgroup. Conclusion In our study, frequency of clinical RBD was unrelated to motor subtypes of PD. However, in the present study, we found a weak correlation between clinical severity (UPDRS and the Hoehn–Yahr) of PD and severity of clinical RBD in the NTD subtype but not in the TD subtype.