April 17, 2003 — According to a recent study, exposing kids to continuous white noise, which is routinely done to calm babies or drown out other noises, may delay their language and hearing development.

According to studies, white noise exposure caused the hearing centres of young rats to fully develop after some time.

White noise, unlike speech or music, is random sound devoid of perceptible pattern and includes radio static and the hum of an air conditioner.

Young rats were exposed to background white noise in the study by Edward Chang and Michael Merzenich, PhD, which was published on April 18 in the journal Science. The white noise was constant, loud enough to mask other environmental sounds but not deafening enough to cause hearing loss. The hearing region of the brains of animals grown in situations with normal environmental sounds was compared.

Researchers found that rats exposed to white noise had much slower growth of the hearing centre of their brains. And these rats’ growth lagged behind that of the rats exposed only when they were three to four times older. Although the maturation of their hearing was delayed, it did reach typical adult levels once they were no longer exposed to the persistent background noise.

Paradoxically, white noise machines and CDs can be purchased for colicky babies and infants who have trouble going asleep.

Chang and Paula Tallal, PhD, a researcher who was not involved in Chang’s study, concur that while regular exposure to white noise is probably safe for most children, intentionally exposing neonates and infants to it for long periods of time is probably not a good idea.

According to Tallal, the lesson is not to keep your baby away from a fan or air conditioner. «Continuous exposure may have an impact on babies who are at risk for learning disabilities, but you must take into account all of a baby’s sound exposures. If you happen to live in an area that is busier than usual, it is extremely important that you spend plenty of time reading to your child or chatting with them in order to expose them to clear [hearing] signals.»

References:

Loud Noise and Pregnancy
White noise enhances new-word learning in healthy adults
How Much the Eye Tells the Brain
Noise-Induced Hearing Loss in Young People