Breath variability increases in the minutes preceding obstructive sleep apneic events.

Purpose: It is unclear if there is a consistent signature in breath patterns prior to an impending obstructive apneic event in patients with sleep-disordered breathing (SDB).

Objective: To use continuous recordings of ambient sound in sleep using a smartphone to track auditory signatures of breaths and measure their regularity preceding apneic events.

Methods: We studied 50 patients evaluated for SDB in whom sound was recorded using smartphones concurrently with polysomnography (PSG).