Subject demographic data.

Subject age, which was relatively normally distributed, is shown as mean±SD, together with age range. Gender is summarized as the percentage of male subjects in each group. Data for disease duration and Parkinson rating scales are presented as median and range because of the skewed nature of their distributions. Statistical comparisons relating to disease duration and Parkinson's disability scales were performed only between PD and APS patients. (RBD = rapid eye movement sleep behavior disorder; APS = atypical Parkinson syndromes; PD = typical Parkinson’s disease; CTL = clinically normal controls; UPDRS = Unified Parkinson’s Disease Rating Scale; NA = not applicable;ap