Sleep disruption, daytime somnolence and ‘sleep attacks’ in Parkinson's disease: a clinical survey in PD patients and age-matched healthy volunteers


Joaquim J. Ferreira, Centro de Estudos Egas Moniz, Faculdade de Medicina de Lisboa, 1649-028 Lisboa, Portugal (tel.: +351 217930629; fax: +351 217957474; e-mail:


Recent case reports of ‘sleep attacks’ (SA) in patients with Parkinson's disease (PD) generated concerns about drug-induced daytime somnolence in this population. However, there are nearly no comparative data on sleep and vigilance problems between PD patients and normal controls. We performed a cross-sectional survey in PD patients and age-matched controls using a structured questionnaire on PD history, treatments, co-morbidity, activities of daily living, habits, exercise, sleep pattern, driving, pre-existing nocturnal problems, daytime somnolence, episodes of SA and the circumstances in which such episodes occurred. Daytime somnolence was also measured with the Epworth Sleepiness Scale (ESS) and sleep quality with the Pittsburgh Sleep Quality Index (PSQI). 176 PD patients and 174 controls were included. The same proportion of PD patients (27%) and controls (32%) reported episodes of SA, but these were more frequent in PD patients and occurred more frequently during situations requiring attention (10.8% vs. 1.7%, p<10−3). More PD patients had abnormal daytime somnolence (ESS) and poor sleeping quality (PSQI). The most consistent factor associated with SA was the duration of levodopa therapy and the predictive value of an abnormal ESS score was rather poor (40.7%). Abnormal daytime somnolence and poor sleep quality at night are more frequent in PD patients than in normals. However, SA are reported in both groups, although less frequently in the normals during activities that requires attention.