Multiple system atrophy manifesting as complex sleep-disordered breathing.

A 56-year-old female presented with multiple system atrophy (MSA) and pure obstructive sleep-disordered breathing (SDB) with an apnea hypopnea index of 29.6/h. However, after the elimination of obstructive events, central apneas emerged with a central apnea index (CAI) of 45.3/h as determined by continuous positive airway pressure titration. Adaptive servoventilation titration decreased the CAI; however, it remained at 14.2/h. There are two different underlying causes of SDB in MSA patients, one is upper airway obstruction at the glottic level, and the other is central components owing to the degeneration of the pontomedullary respiratory centers. Clinicians should recognize that whether a patient has central apnea cannot be determined by diagnostic polysomnography but only after the elimination of upper airway obstruction in MSA patients.