Excessive daytime sleepiness and sleep benefit in Parkinson's disease: A community-based study

The objective of this study was to investigate the frequency of excessive d aytime sleepiness (EDS) and the beneficial effect of sleep on motor perform ance in an unselected community-based sample of patients with Parkinson's d isease (PD). Furthermore, we wanted to identify possible risk factors to th ese phenomena. Detailed information on somnolence and sleep during daytime, as well as sleep benefit (SB) on awakening, was collected through a questi onnaire among 245 patients with PD. Daytime somnolence was graded in groups of no somnolence, mild daytime sleepiness, and EDS. In addition, the occur rence of somnolence in the patients with PD was compared with the occurrenc e among control groups of patients with diabetes mellitus and of healthy el derly subjects. The correlations between EDS and SB and various motor- and non-motor symptoms of PD were evaluated. Among the patients with PD, 15.5% experienced EDS, significantly more than in the patients with diabetes mell itus (4%) and the healthy control subjects (1%). The frequency of mild dayt ime sleepiness was similar (10%) in patients with PD and control subjects. The patients with EDS had significantly higher staging of PD, were more dis abled, and showed a higher frequency of cognitive decline compared with the patients without somnolence. They also had been using levodopa for a longe r time and had more hallucinations. The occurrence of nocturnal sleeping pr oblems and the use of sleeping pills was similar in the two groups, as was the mean age at examination, duration of PD, and presence of fluctuations a nd dyskinesias. SB was found in 42.2% of the patients with PD. These patien ts had been using levodopa for significantly longer and had significantly m ore fluctuations and dyskinesias compared with the patients without SB. Our results suggest that mild daytime sleepiness may be a result of normal agi ng, whereas more severe EDS can be explained by the neuropathologic changes of PD. The data from this community-based study confirms the previously re ported high frequencies of SB.