A new study shows that noise machines, used to help babies fall asleep, can harm infants when played at loud volumes and used too frequently.
Researchers at the University of Toronto tested 14 popular machines that make either ‘white noise’ or nature sounds and are marketed for babies, to lull infants to sleep or drown out noises while babies sleep.
Some machines were capable of producing industrial-scale levels of noise that would be considered excessive in the workplace.
The study, published in early March, 2014, in the journal Pediatrics, found that the noise pressure some machines generated had the potential to affect a child’s hearing, and impair development of speech and language, if machines are used at loud volumes, for extended periods, and are used often.
Maximum sound levels for 65 different noises were tested at three distances from the baby’s head: 30 cm (1 foot), 100 cm (3.3 ft.) and 200 cm (6.6 ft.) — the equivalents of placing a noise machine by baby’s head, near the crib, or across the room.
Researchers found that when volumes were turned up the loudest, 3 of the 14 machines exceeded 85 decibels, the workplace safety limit for adults in an 8-hour shift, for accumulated noise exposure, set by the CDC’s National Institute for Occupational Safety and Health.
In addition to possible hearing damage, the report brought up the possibility that frequent and ongoing moderate or loud noise from a noise machine may delay the development of the hearing centers in the infant’s brain, which could result in speech delays. Infants are learning to distinguish nuances in different sounds, and some baby experts believe that ongoing exposure to loud white noise could cause the baby to be less responsive to soft human speech.
A 2003 study with newborn mice found that when pups were exposed to continuous moderate white noise (such as TV static noise or the noise from a fan), hearing regions of their brains were delayed in development, compared to the brains of pups that were only exposed to usual environmental noises. (Hearing-center delays caught up to normal levels after the pups were no longer exposed to continuous noise.)
Study authors called on manufacturers of noise machines marketed for babies to limit maximum noise levels in their products. They added that safe use of these machines is possible — moving machine farther from baby, lowering the volume and using machine less would all be good steps.
You can also scrap the noise machine altogether, and rely on natural ways to soothe your infant and help them go to sleep, such as cuddling and rocking them gently, singing to them, ‘wearing’ your infant on a sling until you wear them out, or giving long, gentle strokes to your baby’s back and head with your fingertips as you hold baby over your chest.
Partially closing the door in baby’s room will help keep out in-house noise … and if you are unfortunate enough to live in a noisy apartment, a common problem in large American cities, consider moving to a quieter neighborhood. After all, noise pollution is bad for all of us.
By Eirian Hallinan