Volumes of Evidence Link Loud Music, Hearing Loss

Q.My teenage girls live and die by their iPods. Often I can hear their music from across the room, but when I tell them that it is too loud, they say that I'm just being old-fashioned.

Can't loud music cause hearing loss? How can I help my kids avoid damage to their hearing? Or is it crazy to think that loud iPods may make them lose their hearing one day?

A.You can keep trying to convince your children that a loud iPod will hurt their hearing -- or you can let them convince themselves.

It's natural that you tell your girls what to do -- and what not to do -- because you always have, but they're teenagers now and they should be looking for their own answers.

Tell your girls that they can listen to their iPods, but that they'll also have to write a paper about noise-induced hearing loss (NIHL) to see if your advice is really as outdated as they think.

Your girls will learn that sound intensity is measured from zero decibels -- which is almost no sound -- up to 194 decibels, which is the loudest tone humans can hear. Sounds grow 10 times as intense with every 10 decibels. This means that a whisper, 30 decibels, is really 1,000 times louder than zero, and a siren, 120 decibels, is a trillion times louder.

Their research will also teach them that 100 decibels can damage their hearing in only 15 minutes. The louder the noise, the sooner their hearing will be affected, and the closer they are to these sounds and the longer they listen, the greater the damage may be, because all of these episodes produce destructive vibrations. The tips of some sensory hair cells in the inner ear are broken off and can never be replaced. From then on, the quality and the intensity of the sounds that are registered by these cells will never be as good.

If enough cells are killed, your daughters may indeed develop NIHL, particularly if there is any deafness in the family or if the membrane around those hair cells has gotten stiff.

The government has taken NIHL research seriously and now requires employers to lower the noise level in the workplace or to provide ear plugs or headphones if it exceeds 85 decibels for eight hours or more. Even savvy musicians are beginning to wear headphones or vented, custom-fitted ear molds so they can still hear the music around them but with less intensity -- especially the piccolo, which makes the most intense sounds of any musical instrument.

You also should ask your daughters to include the warning signs of hearing loss in their report, from a ringing in one or both ears -- even after things get quiet -- to an inability to hear as well as they used to hear for several hours after the noise goes away.

Your daughters will find this information, and much, much more, on the new site http://www.noisyplanet.nidcd.nih.gov, sponsored by the National Institute of Deafness and Other Communication Disorders and at http://www.listentoyourbuds.org, which is part of the "safe listening" campaign that is being sponsored by the American Speech-Language-Hearing Association and Parents' Choice. Listen to Your Buds features some concerts by the prize-winning children's musician Justin Roberts, who is presenting a show April 29 at Lisner Auditorium.

When your daughters have turned in their report, you might give them a CD, "Turn It to the Left," recorded by Ben Jackson for the American Academy of Audiology and available on YouTube. Or you could download one of the academy's free posters, "Levels of Noise," to remind your girls to wear ear plugs or headphones to their next concert.

These reminders will encourage them to turn the volume down on their iPods; to lower volume on the TV if someone has to yell to be heard; to walk away or simply turn off a noise, rather than listen to it; to turn on only the radio or the television, but not both, and to have at least one quiet area at home where people can go to rest their ears.

Questions? Send them to advice@margueritekelly.com or to Box 15310, Washington, D.C. 20003.