Some sound machines are too loud for babies and can potentially damage infants' hearing and impair auditory development, suggests a new study.
These noise machines create sounds that not only exceed safe levels for children, but also for adults, although the researchers stress that the study's goal was to measure the maximum effective output levels, and not to observe the direct effects these sounds have on children.
"These machines are capable of delivering enough of a dose over a period of time to theoretically cause hearing loss, but that's not been tested," said the study's senior author Dr. Blake Papsin, who is with the University of Toronto and the Hospital for Sick Children in Toronto, according to CNN.
The study's team tested 14 different sleep machines, each at their maximum volume, and analyzed their noise level production from three distances: 30 centimeters, or roughly the distance from a baby's head to the crib rail; 100 centimeters, which would be near the crib; and 200 centimeters, which would be across the room from the crib.
The results showed that three of the noise machines produced sounds greater than the recommended 85 decibels, according to Canadian and U.S. occupational health and safety authorities. These levels are dangerous, especially over an eight-hour period, researchers write, because "infants would be exposed to sound pressure levels that exceed occupational noise limits" for adults for that amount of time.
Based on the study's findings, authors recommend that sound machine manufacturers have a mandatory limit on their maximum output levels, include a warning label about noise-induced hearing loss and have a timer that would shut off the machine after a certain amount of time.
Dr. Harvey Karp, a pediatrician, advises parents to keep any sound machine at the noise level of a "soft shower," and to keep the device at least 30 centimeters away from the child's head.
