Fig. 2From: Prevalence and profile of nocturnal disturbances in Chinese patients with advanced-stage Parkinson’s disease: a cross-sectional epidemiology studyPDQ-39 total and subscale scores for patients with advanced-stage PD with and without ND (all analysis set). *p < 0.001 (with vs without ND). ND, nocturnal disturbance; PD, Parkinson’s disease; PDQ-39, Parkinson’s Disease Questionnaire-39; SEM, standard error of the meanBack to article page