(HealthDay News) — Infant sleep machines (ISMs) have maximum sound levels that may damage infant hearing and auditory development, according to research published online March 3 in Pediatrics.

Sarah C. Hugh, MD, of the University of Toronto, and colleagues measured the sound levels of 14 ISMs at distances of 30, 100, and 200 cm, and used correction factors to account for the ear canal of a 6-month-old infant.

The researchers found that, when played at maximum volume, all of the devices produced output levels at a distance of 30cm that exceeded 50 A-weighted dB, which is the current recommended noise limit for infants in hospital nurseries. Three ISMs generated output levels exceeding 85 A-weighted dB; if played at these levels for more than eight hours, these outputs would exceed current occupational limits of accumulated noise exposure for adults and place listeners at risk for noise-induced hearing loss. For safer use of ISMs, families should place them as far away from the infant as possible and never put them in the crib or on a crib rail; play them at low volume; and operate them for only short periods of time.

“ISMs can generate sound levels in excess of adult occupational noise limits and more conservative limits created for infants in hospital nurseries,” the authors write.

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