How sleep machines can harm your baby’s hearing

Crashing waves, chirping crickets and a pouring rainfall are all white noise provided on sleep machines commonly used by parents to mask household and outdoor noises to ensure a restful night’s sleep for their babies.

But babies who are soothed to sleep with a sound machine may be getting a few extra winks, but the noise may be causing irreparable damage to their hearing, according to new research.

Researchers at the University of Toronto and the Hospital for Sick Children in Toronto studied 14 sleep machines set at maximum volume, measuring the sound produced at distances of 30 cm, the typical distance from a crib rail to a baby’s head; 100 cm, the estimated distance if placed near a crib, and 200 cm, the estimated distance if placed across the room. According to the findings, published this week in the journal Pediatrics, the maximum setting for all 14 devices at a 30 cm distance produced sound that was more than 50 decibels (dB), the current recommended safe noise limit for infants in hospital nurseries.

Three of the machines produced output levels greater than 85 dB, which, if exposed for more than eight hours, “exceeds the current occupational safety limits for accumulated noise exposure in adults and risks noise-induced hearing loss.”

That means babies could be exposed to levels of noise too dangerous for adults, which could affect hearing, speech and language development, and could potentially cause possible hearing impairment.

“We understand that life gets loud, but to me, it doesn’t make sense to drown out noise with other noise,” says Dr. Blake Papsin, principal investigator of the study, in a news release. “We know that parents are trying to do what’s best for their babies and their sleep, so we hope this study informs the public about the potential harms, and educates them on appropriate use of the machine.”

If parents decide to use a sleep machine, the researchers recommend placing it as far away from the infant as possible, setting it at a lower volume and using it for a shorter period of time.

“The limit for nurseries is 40 dB. This limit isn’t very high, when you think about it in comparison to other everyday noises,” says Dr. Kamala Ghaey, pediatrician at Advocate Illinois Masonic Medical Center in Chicago. “90 dB is about the level of a truck without a muffler. And 70 dB is about the level of the average radio or street noise.”

Dr. Ghaey says she agrees with the researcher’s recommendation to increase the distance of the sound machine from baby’s crib. In addition, there are other low-volume noise-producing items that can be used as an alternative, such as a humidifier or vaporizer, which produce a lower level of pitch than sound machines.

In addition, she says music played at a low volume can be a good alternative, as the tones vary in frequency and intensity over the course of a song.

“With or without the noise, children usually sleep quite well,” Dr. Ghaey says. “Children learn to accommodate to the everyday sounds to which they are exposed. So a sound machine, many times, isn’t necessary.”