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Open Access Research article

Daytime sleepiness in Japanese patients with multiple system atrophy: prevalence and determinants

Takayoshi Shimohata1*, Hideaki Nakayama2, Masahiko Tomita3, Tetsutaro Ozawa1 and Masatoyo Nishizawa1

Author affiliations

1 Department of Neurology, Brain Research Institute, Niigata University, Niigata, Japan

2 Division of Respiratory Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

3 Department of Otolaryngology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan

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Citation and License

BMC Neurology 2012, 12:130  doi:10.1186/1471-2377-12-130

Published: 1 November 2012

Abstract

Background

The recent SLEEMSA study that evaluated excessive daytime sleepiness (EDS) in Caucasian patients with multiple system atrophy (MSA) demonstrated that EDS was more frequent in patients (28%) than in healthy subjects (2%). However, the prevalence and determinants of EDS in other ethnic populations have not been reported to date.

Methods

We performed a single-hospital prospective study on patients with probable MSA. To ascertain the prevalence and determinants of EDS in Japanese MSA patients, we assessed the patients’ degree of daytime sleepiness by using the Japanese version of the Epworth Sleepiness Scale (ESS). In addition, we investigated the effects of sleep-disordered breathing (SDB) and abnormal periodic leg movements in sleep (PLMS), which were measured by polysomnography, on the patients’ ESS scores.

Results

A total of 25 patients with probable MSA (21 patients with cerebellar MSA and 4 patients with parkinsonian MSA) were included in this study. All patients underwent standard polysomnography. The mean ESS score was 6.2 ± 0.9, and EDS was identified in 24% of the patients. SDB and abnormal PLMS were identified in 24 (96%) and 11 (44%) patients, respectively. The prevalences of EDS in patients with SDB and abnormal PLMS were 25% and 18%, respectively. No correlations were observed between ESS scores and the parameters of SDB or abnormal PLMS.

Conclusions

The frequency of EDS in Japanese patients with MSA was similar to that in Caucasian MSA patients. SDB and abnormal PLMS were frequently observed in MSA patients, although the severities of these factors were not correlated with EDS. Further investigations using objective sleep tests need to be performed.

Keywords:
Multiple system atrophy; Excessive daytime sleepiness; Epworth Sleepiness Scale; Sleep-disordered breathing; Abnormal periodic leg movements in sleep