Does multiple system atrophy itself affect sleep structure?

OBJECTIVES: Reports on sleep in multiple system atrophy (MSA) are rare and many confounding variables affect the results. Among them, obstructive sleep apnea and periodic limb movements during sleep are very common. We conducted this study to see the changes of sleep parameters originating from MSA itself without confounders. METHODS: We compared polysomnographic variables of 15 MSA patients and 15 age-, gender-, apnea-hypopnea index-, and periodic limb movements index-matched controls. We also applied cyclic alternating pattern scoring in 7 MSA patients and 7 controls. RESULTS: Total sleep time and sleep efficiency are decreased in MSA. Wake after sleep onset, sleep onset latency, and stage 2 latency are prolonged. There is no difference in the proportion of slow wave sleep and rapid eye movement sleep between MSA patients and the controls. Cyclic alternating pattern scoring shows no difference, either. CONCLUSIONS: MSA itself does not affect the macro- and microstructures of sleep. However, patients with MSA sleep less and it cannot be explained by obstructive sleep apnea and periodic limb movements during sleep.