Psychometric properties of the Parkinson's Disease Sleep Scale – Brazilian version

Parkinson's Disease Sleep Scale (PDSS) is a specific scale for the assessment of sleep disturbances in subjects with Parkinson's Disease (PD). This cross-sectional study set out to validate the PDSS in a Brazilian Portuguese Version (PDSS-BR). Ninety-five patients with PD participated in the study; their PD symptoms were evaluated by Unified Parkinson's Disease Rating Scale (UPDRS sections I–IV) and Hoehn and Yahr scale. Patients completed Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI) and PDSS-BR. PDSS-BR internal consistency was satisfactory (Cronbach's α: 0.82; all PDSS-BR items were significantly and positively associated with total score). Test–retest reliability for total PDSS-BR score was 0.94. PDSS-BR score was highly correlated with sleep PSQI scale (rs = −0.63; p < 0.0001) and moderately with ESS (rs = −0.32; p < 0.001) and UPDRS sections I (rs = −0.38; p < 0.0001) and II (rs = −0.36; p < 0.0001) and BDI (rs = −0.55; p < 0.0001). Depressive symptoms, as determined by the BDI, were associated with significantly worse quality of nocturnal sleep, as measured by the PDSS-BR.The psychometric attributes of the PDSS-BR were satisfactory and consistent with those of previous studies. In summary, PDSS-BR can be useful for clinical and research purposes in Brazil.