Many parenting Web sites encourage use of infant "sleep machines" to play ambient noise while infants sleep. Noise recommendations for hospital nurseries suggest a limit of 50 A-weighted dB, whereas occupational standards limit exposure times for noise >85 A-weighted dB.

We measured the maximum sound level outputs of infant sleep machines and found that several devices are capable of producing levels that may be damaging to infant hearing and may be detrimental to auditory development. (Read the full article)