A comparative study on clinical rapid eye movement sleep behavior disorder and motor subtypes in outpatients with Parkinson′s disease

Objective To investigate the incidence and severity of clinical rapid eye movement sleep behavior disorder (RBD) in Parkinson′s disease (PD), and the association with motor subtypes. Methods We recruited 187 patients with PD(Hoehn-Yahr stageⅠ-Ⅲ) from outpatient department in Beijing Hospital. The general information of the patients was collected and the Unified Parkinson′s Disease Rating Scale (UPDRS) scores were caculated. The patients were divided into two subgroups as tremor dominant (TD) and non-tremor dominant (NTD). One hundred matched healthy controls (HC) were enrolled. We used the minimal diagnostic criteria of parasomnias described in the International Classification of Sleep Disorders-Revised to diagnose clinical RBD. The Stavanger Sleepiness Questionnaire (SSQ) was used to rate the severity of clinical RBD. The PD group and HC group were compared with incidence of clinical RBD. The TD subgroup and NTD subgroup were compared with each other for severity and incidence of clinical RBD, the UPDRS scores and disease duration. The correlation between severity of clinical RBD and clinical severity of PD was analyzed in the patient groups. Results The incidence of clinical RBD in PD and HC groups was 46.5% (87/187) and 5.0% (5/100). The difference between two groups was significant (χ2=1.537, P=0.000). Of the patients, 36.4% (68/187) had the NTD subtype of PD. There were no significant differences in the incidence and severity of clinical RBD between NTD subtype and TD subtype. For the NTD patients, there was positive correlation between severity of clinical RBD (SSQ scores) and clinical severity (UPDRS scores and the Hoehn-Yahr stage) of PD(r=0.266, P=0.028; r=0.263, P=0.030). Conclusion In our study, incidence of clinical RBD is unrelated to motor subtypes of PD. There is a positive correlation between clinical severity of PD and severity of clinical RBD in the NTD subtype but not in the TD subtype. Key words: Parkinson disease; Eye movements; Conduct disorder; Sleep