Nocturnal stridor in olivopontocerebellar atrophy.

We describe a patient with olivopontocerebellar atrophy (OPCA) who was referred for alleged "snoring." Polysomnogram with video and audio monitoring revealed that the patient actually had nocturnal stridor causing repetitive oxygen desaturations. Direct laryngoscopy while awake showed a unilateral vocal cord paralysis. The nocturnal stridor persisted after unilateral vocal cord pinning, suggesting that the patient had probably been experiencing bilateral vocal cord paresis while asleep. We conclude that state-dependent vocal cord dysfunction may be severe in OPCA and related multiple system atrophy. Nocturnal stridor has many causes and may mimic snoring and obstructive sleep apnea syndrome. Polysomnography with audio and video recordings are necessary to make the diagnosis.