Effects of two types of ambient sound during sleep

This field study investigated whether either of two ambient sounds would improve objective sleep (via actigraphy), subjective sleep report, or morning psychomotor performance among 28 adults with self-described disturbed sleep. Nights 1 and 4 were soundless baseline and washout, respectively. On Nights 2 and 3 and 5 and 6, participants listened to double-blind counterbalanced paired nights of novel Sound A and a commercially available Sound B. Compared to baseline and washout, participants reported fewer awakenings during both Sound A and Sound B; actigraphically measured sleep was affected by Sound B but not Sound A. "Improvements" in sleep during the second exposure night probably reflect an increase in homeostatic sleep drive from sleep disturbance on the first exposure night. Differences between sounds were accounted for by user volume settings. Neither sound led to differences in psychomotor performance.