Can Sleep Machines Damage Infant Hearing?

Summary and Comment |
April 18, 2014

Can Sleep Machines Damage Infant Hearing?

  1. Louis M. Bell, MD

The decibel levels produced by some machines exceed occupational safety recommendations for adults and maximum safe noise exposure for infants.

  1. Louis M. Bell, MD

A noisy environment might disturb an infant's (and parent's) sleep. Infant sleep machines (ISMs) are designed to provide ambient noise to soothe infants to sleep or mask disturbing environmental sounds. As ISMs become more popular, some ostensible baby sleep experts and websites recommend use of ISMs during all sleep at a volume equal to the infant's cry. The U.S. and Canadian occupational safety recommendations for work place noise set a limit of ≤85 A-weighted decibels (dBA) for an 8-hour period. The recommended noise limit in infant nurseries and neonatal ICUs is 50 dBA averaged over 1 hour. In comparison, ambient noise is <25 dBA.

Researchers purchased 14 ISMs that are commercially available in the U.S. and Canada and measured sound levels at maximum volume from three distances: 30 cm (placement on a crib rail), 100 cm (near a crib), and 200 cm. The sound level meter microphone was adapted to simulate an infants' ear canal. The mean maximum output of the ISMs was 79 dBA at 30 cm, 71 dBA at 100 cm, and 63 dBA at 200 cm. Three ISMs produced noise >85 dBA at 30 cm, exceeding maximum work place noise levels for adults. All but one ISM produced noise levels >50 dBA — the maximum for infants — at all three distances.

The authors provide the following recommendations for families:

  • Place the ISM as far away as possible from the infant and never in the crib or on the crib rail.

  • Play the ISM at the lowest volume possible.

  • Operate the ISM for a short duration (until noise levels diminish or the infant is sleeping soundly.


The concerns and recommendations for safer use of infant sleep machines seem prudent until we understand whether these devices damage infant hearing and auditory development. The authors encourage manufacturers to limit dBA output, print warnings, and include timers on the devices to automatically shut off.

Editor Disclosures at Time of Publication

  • Disclosures for Louis M. Bell, MD at time of publication Grant / research support Institutional Clinical and Translational Science Award; National Center for Pediatric Practice Based Research Learning Editorial boards Current Problems in Pediatric Adolescent Healthcare Leadership positions in professional societies Academic Pediatric Association (Chair, Academic General Pediatrics Fellowship Accreditation Committee)


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