White noise may be too loud for babies
If a so-called white noise machine is kept at full volume in a room with a sleeping baby, it may be potentially hazardous to the child’s hearing, suggests a new study.
The study cannot say exposure to the machines is impairing children’s hearing — just that the devices may be capable of creating sounds loud enough to cause hearing loss after prolonged exposure.
The report’s author from the Hospital for Sick Children in Toronto told Reuters people should consider sound in terms of dose.
White noise machines produce sounds to soothe infants to sleep and help mask other noises, Dr. Blake Papsin and his colleagues write in the journal Pediatrics.
But noise can cause hearing loss at certain levels, and the ears of young children are different from adult ears.
The researchers wrote that the National Institute for Occupational Safety and Health recommend adults limit workplace sound exposure to no more than 85 A-weighted decibels for eight hours.
For young children, it has been recommended that they not be exposed to more than 50 dBA averaged over an hour.
For the study, the researchers bought 14 different types of white noise machines off the Internet and in traditional brickand-mortar stores.
Using a sound booth, the researchers tested each device turned to its maximum volume and placed sound meters at varying distances to simulate the machine hanging on the side of a crib and being across the room.
Three machines were capable of producing noise in excess of 85 dBA when positioned on the side of the crib. All machines were capable of producing sounds greater than 50 dBA when placed on the crib. And all but one of the machines were capable of producing sounds greater than 50 dBA from across the room.