History of symptoms consistent with REM sleep behavior disorder in a population with Parkinson's Disease

REM Sleep Behavioral Disorder (RBD) is a parasomnia marked by the maintenance of muscle tone during REM sleep. Evidence has placed RBD as one of the possible prodromal stages of Parkinson's Disease (PD), but data on the proportion of people with PD who have had symptoms of RBD are limited. This study aimed to investigate the history of symptoms compatible with RBD in a population with PD. The sample was composed by 73 patients with clinically diagnosed PD being followed up at a reference outpatient setting, compared to 73 age- and sex-matched individuals with no PD. The evaluation of symptoms compatible with RBD was performed using the Brazilian version of the RBD Screening Questionnaire (RBDSQ). The prevalence of symptoms compatible with RBD was 65 % for PD and 10.09 % for controls. The RBDSQ score was significantly higher in the PD group (6.03 ± 0.35) in comparison to the control group (2.38 ± 0.23). The odds ratio for presenting previous RBD-compatible symptoms was 12.09 in favor of positive PD cases. PD diagnosis has the following diagnostic properties in relation to presenting RBD symptoms: sensitivity of 0.65, specificity of 0.86, positive predictive value of 0.82 and negative predictive value of 0.71. In conclusion, the proportion of PD patients showing RBD symptoms is high, corroborating the expected neuroprogression of the disease on a case-control design comprising outpatient PD cases. Clinical practitioners should include evaluations of RBD-compatible symptoms during the PD assessment and, if positive, forward to a sleep specialist.