Why does it happen?

The most common cause of hearing loss is loud noises. Although you may not feel pain until the sound reaches 125 decibels—about the level of an exploding firecracker—damage can occur at lower decibel levels. Certain drugs, including some antibiotics, chemotherapies and even aspirin, as well as infections of the middle and inner ear, can also lead to hearing loss.

What are the signs?

Most hearing loss is gradual. In fact, family and friends are often the first to notice it. Some common signs of damage:

-Speech sounds muffled, especially over the phone

-Difficulty hearing when there is background noise

-Asking others to speak more slowly, loudly or clearly

-Needing to turn up the volume of the television or stereo

What tests should you have?

If you suspect you're losing your hearing at any age, seek out a licensed audiologist for baseline audiometric testing. (Wearing headphones in a sound booth, you'll be asked to identify the softest beep you can hear and repeat words and sentences.) She may also conduct tests of your middle ear function.

What are your options?

Once hearing is damaged, experts can only focus on improving the sound of what you still hear.

-For mild to profound hearing loss, hearing aids amplify sound and let you carry out everyday activities without difficulty.

-For severe or profound hearing loss, a cochlear implant (a small electronic device surgically placed underneath the skin just behind the ear with electrodes leading into the inner ear) can re-create a sense of sound and help you understand speech.

How can you protect your ears?

The long battery life of MP3 players means you can listen to music at loud levels for hours at a time—a dangerous combination. Apple offers a noise limit feature on its iPods that lets you set a safe maximum volume. You should also wear earplugs or muffs when exposed for an extended period of time to noise that is 90 decibels or louder.

Did you know?

-About 28 million Americans have hearing loss, and more than 30 million are exposed to dangerous noise levels each day.

-Forty percent of all cases of hearing loss are preventable.

-One loud rock concert, at 120 decibels, can cause damage in just 7½ minutes.

"We live in a noisy world. But our ears don't split open and start bleeding when we damage them. So you can have quite a bit of hearing loss before you know it."

Catherine Palmer, Ph.D., head of the Center for Audiology and Hearing Aid Services, University of Pittsburgh Medical Center

Want to know more?

-Find an audiologist at audiology.org, the website of the American Academy of Audiology.

-Learn more about safe noise levels at betterhearing.org or call 1-800-EAR-WELL.

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