Reliability And Validity Of Parkinson’s Disease Sleep Scale-2

Objective:To assess the reliability and validity of Parkinson’s disease sleep scale-2(PDSS-2),and to determine the PDSS-2 cut-off values that define the sleep disturbances in Parkinson’s disease(PD)patients.Methods:70 patients with PD who came to the Neurology Departnent in the Second Affiliated Hospital of Soochow University from December 2017 to October 2018 and 72 age-and gender-matched control subjects were enrolled in our study.We collected the demographic date,and assessed the Unified parkinson’s disease rating scale,Hoehn-Yahr stage,Montreal cognitive assessment,Hamilton depression scale,Pittsbuigh sleep quality index,PDSS-2,etc.The internal consistency was tested by Cronbach’s alpha coefficient(Cronbach’s α)and the test-retset reliability was tested by intraclass correlation coeficient(ICC).The content validity was tested by Spearman rank correlation coefficient.The cut-off value was assessed using the receiver operator characteristics curves(ROC curve).Results:A satisfactory internal consistency and test-retset reliability score were obtained for the PDSS-2 total score(Cronbach’s α=0.84,ICC=0.85).The PDSS-2 score was correlated with the disease duration,the severity of disease,levodopa dosage,motor symptoms,eognitive level,depression and the quality of life(P<0.05).ROC curve revealed that score of 12 points was the best cut-off value,respectively:sensitivity 91.89%,specificity 75.76%,Positive predictive value 80.95%,negative predictive value 89.29%,area under curve 0.84.Conclusions:PDSS-2 is a reliable and valid tool for measuring sleep disorders in PD patients.We suggest that PDSS-2 total scores>12 are useful to define PD-specific sleep disturbances.