Protecting your hearing in today's technological world

It seems everywhere you look these days, people are plugged in. They have wireless ear pieces for their cell phones, earbuds for their MP3 players and stereo headsets for lounging at home.

Technology adds to our productivity and provides entertainment, but it also can hurt our hearing.

"We're getting more exposure to loud sounds when we're already in a very loud world," said Andrew J. Vermiglio, a doctor of audiology and senior research associate for House Ear Institute in Los Angeles. "Anytime you're in an environment where you have to raise your voice to be heard, it's potentially hazardous to your hearing."

Sound enters the ear and travels through the ear canal. It hits the eardrum and vibrates the little bones behind it, which in turn vibrate the structures inside the cochlea. The cochlea contains the nerve endings that transfer sound to our brains. If the noise is too loud, it can damage the delicate parts of the ear.

"Even though the person is totally enjoying the music or the broadcast, they can do a lot of destruction to the inside of their cochleas," Vermiglio said.

The damage in the cochlea affects the outer hair cells that allow us to hear speech in a noisy background. as well as very soft sounds. If the outer hair cells do not function fully, the ability to pick up soft sounds begins to disappear and then, as damage continues, you begin to lose the ability to hear louder noises.

It is tough to obtain exact statistics on noise-induced hearing loss because it is hard to control every aspect of what someone hears, although studies do exist. In the distant past, doctors and scientists were allowed to expose people and animals to high levels of sound and then measure the damage. From this research, doctors today can provide information to warn and help the public.

Noise exposure adds up both over time and according to the level of the sound, Vermiglio said. If you work in a loud environment and go home and turn up the volume on your MP3 player or stereo, you're adding to the potential damage of your cochlea.

One way to control volume is by using earphones or earbuds that have a good seal, making them similar to an earplug. The goal is to minimize the ambient noise in your environment so you can listen to your music or program at a lower volume. But even if your earphone has a good seal, you can still be tempted to make it louder. And that's where the damage happens.

"I used to tell my son, `If I can sing along with the song that you're listening to with your earbuds and you're in the living room and I'm in the kitchen, it's way too darn loud,"' Vermiglio said.

The House Ear Institute has informally measured decibel levels of iPods and found that at full volume, they can be 110-115 dB depending on the earphones. This is louder than the average rock concert, which clocks in at 100 dB. The Occupational Safety and Health Administration says people should spend no more than 15 minutes to a half-hour in such an environment. The National Institute for Occupational Safety is even more strict, saying more than a minute and a half exposed to this rate of noise is not safe.

If you wear an earpiece for your cell phone, you must exercise caution too, as you are competing with outside noises, whether it is a busy shopping center or another conversation nearby. Instead of turning the volume up to an unsafe level, consider continuing the conversation in a quieter area.

Indications of hearing damage include ringing in the ear (tinnitus) and loss of the ability to detect high frequency sounds. If you are listening to someone speak, you may notice sounds like an "s" or "f" are beginning to disappear. You may find yourself telling the speaker not to raise their voice, as you can hear them fine, but you cannot understand what they are saying; the words are fuzzy or muffled as if the speaker is holding a hand over their mouth.

Another common symptom is being unable to understand a conversation in a noisy environment such as a loud restaurant or wedding reception.

"Your ability to carry on conversation or understand conversations with background noise will start to decrease," Vermiglio said. "A lot of times you will notice, `Wow, I'm not having a lot of fun at this party because I can't understand who I'm talking to at all,' whereas years before you could understand them.

"If you notice a change in your hearing, immediately go see an audiologist or ear, nose and throat doctor," Vermiglio said.

Hearing loss can be attributed to exposure to loud sounds, but it can also be caused by other conditions, such as a sinus or middle ear infection, or even a life-threatening condition like a tumor growing on a nerve inside the ear. If the tumor grows large enough, it can push into the brain.

Vermiglio recommends that everyone who uses MP3 players, cell phones and other devices that require earphones or spends time in a noisy environment have their hearing tested once each year.

Pure Tone Testing is the standard hearing test. That's when you are in a sound-controlled booth, and everytime you hear a sound, you press a button. There are two other tests that can detect hearing damage before it shows up in the standard test.

An otoacoustic emissions screening measures the sound that the ear makes and can detect damage to the outer hair cells of the cochlea. The cells are made of protein fibers, similar to muscles, and can contract and expand, as well as create vibrations that go out of the ear. This effect indicates a healthy ear, as things are working as they should.

A speech recognition and noise exam, such as the House Ear Institute's Hearing and Noise Test (HINT), charts your ability to understand speech against background noises. The loss of this ability may have occurred even if an audiogram indicates your hearing as normal.

Vermiglio is a drummer. He played in the military and professionally for 20 years and still plays, studies and teaches. He points out that musicians as a good example of people who may have normal hearing according to Pure Tone Testing, but that they have damage detected by the other two screenings.

Vermiglio is an advocate for earplugs to stave off hearing loss in loud environments. For music lovers and players, he recommends Musician's Earplugs or another type of high-fidelity earplug. Standard earplugs tend to wipe out the high frequencies and make the music sound muddy, while these let sounds ring out true and safely so they can be heard at a lower volume.

"Earplugs are relatively inexpensive, but hearing aids can be extremely expensive, thousands and thousands of dollars for these things, and you have to replace them every five to seven years or so," Vermiglio said. "There's amazing technology out there, but it will never ever replace normal ears."