Excessive daytime sleepiness in multiple system atrophy (SLEEMSA study)

BACKGROUND: Sleep disorders are common in multiple system atrophy (MSA), but the prevalence of excessive daytime sleepiness (EDS) is not well known. OBJECTIVE: To assess the frequency and associations of EDS in MSA. DESIGN: Survey of EDS in consecutive patients with MSA and comparison with patients with Parkinson disease (PD) and individuals without known neurologic disease. SETTING: Twelve tertiary referral centers. PARTICIPANTS: Eighty-six consecutive patients with MSA; 86 patients with PD matched for age, sex, and Hoehn and Yahr stage; and 86 healthy subject individuals matched for age and sex. MAIN OUTCOME MEASURES: Epworth Sleepiness Scale (ESS), modified ESS, Sudden Onset of Sleep Scale, Tandberg Sleepiness Scale, Pittsburgh Sleep Quality Index, disease severity, dopaminergic treatment amount, and presence of restless legs syndrome. RESULTS: Mean (SD) ESS scores were comparable in MSA (7.72 [5.05]) and PD (8.23 [4.62]) but were higher than in healthy subjects (4.52 [2.98]) (P < .001). Excessive daytime sleepiness (ESS score >10) was present in 28% of patients with MSA, 29% of patients with PD, and 2% of healthy subjects (P < .001). In MSA, in contrast to PD, the amount of dopaminergic treatment was not correlated with EDS. Disease severity was weakly correlated with EDS in MSA and PD. Restless legs syndrome occurred in 28% of patients with MSA, 14% of patients with PD, and 7% of healthy subjects (P < .001). Multiple regression analysis (with 95% confidence intervals obtained using nonparametric bootstrapping) showed that sleep-disordered breathing and sleep efficiency predicted EDS in MSA and amount of dopaminergic treatment and presence of restless legs syndrome in PD. CONCLUSIONS: More than one-quarter of patients with MSA experience EDS, a frequency similar to that encountered in PD. In these 2 conditions, EDS seems to be associated with different causes