ABSTRACT
Parkinson’s disease (PD) is a neurodegenerative disorder with a multifactorial etiology, but it is primarily suggested to be due to a loss of dopaminergic function, which produces multiple neurological and psychiatric symptoms, including motor, cognitive, and emotional dysfunction. Additionally, most patients with PD experience sleep-related symptoms, including difculty in initiating and maintaining sleep, excessive daytime sleepiness (EDS), and parasomnias such as rapid eye movement (REM) sleep behavior disorder (Kumar et al. 2002; Brotini and Gigli 2004; Postuma et al. 2009). Most studies point out that the prevalence of sleep disturbance in PD is nearly 100% (Lees et al. 1988; Kumar et al. 2002; Poryazova and Zacchariev 2005). These sleep disorders are classi-ed as primary sleep disorders that are intrinsic to PD and secondary sleep disorders due to either medications or motor impairment (Friedman and Chou 2004). Most studies have shown that the use of dopamine (DA) agonists cause somnolence with a reversal of the sleep-wake cycle (Ondo et al. 2001; Sanjiv et al. 2001).
