Are you using a white-noise machine to lull your own little noisemaker to sleep? If you’re not careful, you could do irreparable harm to your baby’s hearing.
That’s the conclusion of a study published today by the official journal of the American Academy of Pediatrics. Researchers at the University of Toronto evaluated 14 popular machines that emit ocean sounds, heartbeats and other ambient noise to help send infants off to slumberland. Some are shaped like stuffed animals and designed to attach to a crib or a stroller.
At full volume, these infant sleep machines produced between 69 and 93 decibels of sound approximately one foot from the child’s ears — somewhere between the sound of a vacuum cleaner and a passing subway train, according to guidelines published by the American Speech Language Hearing Association.
Three of the units exceeded 85 decibels, the workplace safety limit for adults established by the National Institute for Occupational Safety and Health. The report does not indicate which brands of machine it tested.
“These machines are capable of delivering noise that we think is unsafe for full-grown adults in mines,” senior researcher Dr. Blake Papsin told the New York Times.
Image: Baby Einstein
Aside from damaging a child’s hearing, researchers warned that prolonged exposure to loud noise could theoretically delay development of the brain’s auditory cortex, citing a 2003 study on rats.
The report urges manufacturers of such devices to limit their maximum output, to add warning labels and to install timers that automatically shut machines off after a specified period.
In the meantime, parents can reduce the risk substantially by moving the machines farther from the child, turning down the volume and not leaving them on all night.
Unless, of course, you want to spend the rest of your life yelling at your kids and having them really be unable to hear you, instead of just pretending not to.