“…Some authors have argued that EDS could be an integral part of PD rather than the result of poor nighttime sleep quality (Goldman et al., 2013). In addition, whether clinical characteristics such as disease severity, Unified Parkinson's Disease Rating Scale (UPDRS) score, and the prescription of dopaminergic medication are risk factors for sleep disturbance remains controversial (Hoglund, Broman, Palhagen, Fredrikson, & Hagell, 2015; Kumar, Bhatia, & Behari, 2002; Ondo et al., 2001; Pandey, Bajaj, Wadhwa, & Anand, 2016; Svensson, Beiske, Loge, Beiske, & Sivertsen, 2012; Tholfsen, Larsen, Schulz, Tysnes, & Gjerstad, 2015). …”