You turn on a white noise machine to help your baby sleep by masking background noise, but is it safe? Maybe not, according to a new study. Canadian researchers found that if a sleeping baby is exposed to a white noise machine at full volume over a prolonged period of time, he or she may experience hearing loss.
Dr. Blake Papsin from the Hospital for Sick Children in Toronto is lead author of the study, and he and his colleagues noted in the journal Pediatrics that any noise (even from a sound-masking white noise machine) can cause hearing loss at a certain level; the ears of infants and young children are more sensitive since higher-frequency sounds get amplified by smaller ear canals.
To conduct their research, the doctors purchased 14 different types of white noise machines online and at traditional brick-and-mortar retailers. The machines produced 65 different sounds, including noises found in nature and heartbeat sounds. Each device was tested in a sound booth and at maximum volume, and tested to reflect how a machine would be placed in a nursery (from on the side of the crib to across the room). Microphones for the sound metres were fixed with attachments to simulate ear canals.
Young children, the doctors report, shouldn’t be exposed to sound greater than 50Dba (the equivalent of a dishwasher running in an adjacent room) for more than an hour. However, three of the machines tested were capable of producing noise in excess of 850Dba when positioned on the side of a crib; all of the machines, when positioned on or near to the crib, produced sound in excess of 50Dba. All but one machine could produce at least that 50Dba level from across the room. Based on the results, the research suggests that parents place the machines as far away from the infant as possible and keep the volume turned to the lowest level.
Dr. Papsin said he is not recommending that parents get rid of their machines. The study is intended to give parents more information so they can decide what noise in the baby's environment needs to be mitigated and to take appropriate caution when using white noise machines.