Observational study of sleep-related disorders in Italian patients with Parkinson's disease: usefulness of the Italian version of Parkinson's disease sleep scale

Sleep disturbances are common in patients with Parkinson's disease (PD). We aimed to evaluate prevalence and severity of nighttime sleep disturbances in Italian PD patients and to validate the Italian version of the Parkinson's disease sleep scale. A total of 221 PD patients and 57 healthy controls participated in a cross-sectional study with retest. PDSS, Epworth Sleepiness Scale (ESS), Hamilton Depression Rating Scale, Unified Parkinson's Disease Rating Scale (UPDRS), and Hoehn and Yahr staging were applied. PDSS total and individual items scores from patients were significantly lower than those in controls. Internal consistency of PDSS scale was satisfactory and intraclass correlation coefficient for test-retest reliability was 0.96 for total PDSS score. A significant negative correlation was found between total PDSS and ESS scores, and between total PDSS and HDRS scores. PDSS scores were also related to UPDRS sections II, III and IV, and H&Y stage. PDSS and ESS scores were not related to levodopa equivalent dose. Daytime sleepiness, depressive symptoms and disease severity correlate with sleep disturbances in Italian PD patients. The PDSS is a valid and reliable tool to evaluate sleep disturbances in Italian patients.