April 17, 2003 — A recent study reveals that subjecting children to continuous white noise, which is frequently done to calm infants or block out other stimuli, may postpone the development of their hearing and possibly their language skills.
Young rats’ hearing centres did not fully mature until after exposure to continuous, random noises, such as white noise, according to researchers.
White noise, which includes radio static and the hum of an air conditioner, is random sound devoid of audible pattern, unlike speech or music.
In their study, which was released on April 18 in the journal Science, Edward Chang and Michael Merzenich, PhD, subjected young rats to background white noise that was constant and loud enough to hide other environmental sounds but not so loud as to cause hearing loss. Animals raised in environments with typical environmental sounds were compared in terms of the development of the brain’s hearing region.
The growth of the brain’s hearing centre was significantly delayed in the rats subjected to white noise, the researchers discovered. And these rats’ development did not catch up to that of the rats who were not exposed until they were three to four times older. Although the development of their hearing was delayed, after they were no longer exposed to the constant background noise, it did mature to normal adult levels.
Ironically, colicky babies and babies who have problems falling asleep can buy white noise machines and CDs.
Both Chang and Paula Tallal, PhD, a researcher who was not involved in Chang’s study, agree that purposely subjecting neonates and infants to uninterrupted white noise is probably not a good idea, but that regular exposure is probably safe for most kids.
The lesson is not to keep your child away from a fan or air conditioner, according to Tallal. «Babies who are at risk for learning difficulties may be affected by continuous exposure, but you must consider all the sound exposures a baby receives. Spending plenty of time reading to your kid or conversing with them in order to expose them to clear [hearing] signals is especially crucial if you happen to live in an area that is busier than usual.»