As one site explains:
-- http://emedicine.medscape.com/article/304967-treatmentNo clear guidelines are available on when or whether to treat central sleep apnea in the absence of symptoms, particularly when central sleep apnea is discovered after polysomnography (PSG) is performed for another reason. Clearly, when the symptoms are present, treatment is warranted. The decision to treat should be made on an individual basis.
Up to 20% of central sleep apnea cases have been suggested to resolve spontaneously. If the patient is not symptomatic, observation may be the only appropriate step. This may be the case in patients who have central sleep apnea during sleep-wake transition, patients without significant oxygen desaturation, or in those who experience central sleep apnea during continuous positive airway pressure (CPAP) treatment of obstructive sleep apnea.
If present, treatment of the underlying disorder often improves central sleep apnea.
So some might argue that the point is to treat obstructives first, then to worry about any residual centrals later, within reason, if no serious underlying cause, beyond OSA, is found.
An unpopular thought, perhaps, but something worth thinking about, to my mind.