Daytime sleepiness in Parkinson's disease

We describe multiple sleep latency test (MSLT) results in 27 adult patients with idiopathic Parkinson's disease (PD). Pathological sleepiness (i.e. me an sleep latency less than or equal to 5 min) was common (40 of 134 nap opp ortunities), and sleep-onset REM periods were also observed (13 of 134 nap opportunities). These findings bore little relationship to disease specific variables (e.g. level of disability, medication use), or sleep architectur e measures (e.g. total sleep time, sleep stage percentage's). Our findings speak against a simple association of excessive sleepiness and the quality and quantity of prior night's sleep, but rather, argue for primary impairme nts of waking arousal and REM-sleep expression in a sizeable subpopulation of PD patients.