Hearing: Noise-Induced Hearing Loss

Noise-induced hearing loss is permanent hearing loss that is caused by being around loud noises over a long period of time. It can also occur after you are exposed to loud noise in a short period of time, such as a gunshot or explosion. The more you are around loud noises, the more you risk having hearing loss.

Whether noise harms your hearing depends on the loudness, the pitch, and the length of time you are exposed to the noise. The loudness of a sound (measured in decibels, or dB) and the length of exposure are related. The louder the sound, the shorter the exposure can be before damage occurs. For example, 8 hours of exposure to 85-dB noise on a daily basis can begin to damage a person’s ears over time. Using power tools (at about 100 dB), listening to loud stereo headsets (at about 110 dB), attending a rock concert (at about l20 dB), or hearing a gunshot (at 140 to 170 dB) may damage the hearing of some people after only a few times.

Symptoms of noise-induced hearing loss

One reason people fail to notice the danger of noise is that too much exposure to noise causes few symptoms. Hearing loss is rarely painful. The symptoms are usually vague feelings of pressure or fullness in the ears, speech that seems to be muffled or far away, and a ringing sound in the ears that you notice when you are in quiet places. These symptoms may go away minutes, hours or days after the exposure to noise ends.

People assume that if the symptoms go away, their ears have “bounced back” to normal. This is not really true. Even if there are no more symptoms, some of the cells in the inner ear may have been destroyed by the noise. Your hearing returns to normal if enough healthy cells are left in your inner ear. But you will develop a lasting hearing loss if the noise exposure is repeated and more cells are destroyed.

The first sign of a noise-induced hearing loss is not hearing high-pitched sounds, like the singing of birds, or not understanding speech when in a crowd or an area with a lot of background noise. If the damage goes on, hearing declines further, and lower pitched sounds become hard to understand.

How can you decide which noises are too loud?

The following signs should be a red flag that the noise around you is too loud:

  • If you have to shout to be heard above the noise.
  • If you can’t understand someone who is speaking to you from less than 2 feet away.
  • If a person standing near you can hear sounds from your stereo headset while it is on your head.

What causes noise-induced hearing loss?

The human ear is divided into 3 parts — the external, middle, and inner ear. The inner ear is located inside the skull. It is the most complex part of the ear. The soft tissue of the inner ear is made of different types of cells and nerves, all arranged in a pattern on a thin sheet of tissue. Large tubes filled with fluid surround the soft tissue of the inner ear. Hearing loss occurs when the inner ear is damaged.

Frequent exposure to loud or moderately loud noise over a long period of time can damage the soft tissue of the inner ear. Cells and nerves in the inner ear are destroyed by continuous or repeated exposure to loud sounds. If enough cells and nerves are destroyed, hearing is permanently damaged.

How is noise-induced hearing loss diagnosed?

Your doctor can offer a hearing test that will determine if you have a hearing loss. If the test shows that you do have a hearing loss, you will be referred to an audiologist (ear care and hearing loss professionals) or otolaryngologist (a doctor with special training in ear and hearing disorders) for a more thorough hearing test. This test will determine what degree of hearing loss you have (mild, moderate, or profound). It also will identify for which frequencies (sound pitches: high sounds and low sounds) you have a hearing loss. For example, your hearing loss may affect only high frequencies (birds chirping) or low frequencies (a bass drum).

Hearing loss is usually progressive. That means it happens over a long period of time. Because it happens over time, you are less likely to notice that it is happening. If you are having trouble hearing in crowded places or it is difficult to talk on the phone, it may be time for a hearing test.

Can noise-induced hearing loss be prevented or avoided?

Following a few simple steps could protect you from noise-induced hearing loss.

  • Reduce your exposure to noise.This step is especially important for people who work in noisy places and who go to and from work in noisy city traffic. Special earmuffs that protect your ears are available for people who work in noisy environments (such as around heavy machinery). You can also reduce your exposure to noise by choosing quiet leisure activities rather than noisy ones.
  • Develop the habit of wearing earplugs when you know you will be exposed to noise for a long time.Disposable foam earplugs are inexpensive and are available in drugstores. These earplugs, which can quiet up to 25 dB of sound, can mean the difference between a dangerous and a safe level of noise. You should always wear earplugs when riding snowmobiles or motorcycles, attending concerts, when using power tools, lawn mowers or leaf blowers, or when traveling in loud motorized vehicles.
  • Use sound-absorbing materials to reduce noise at home and at work.Rubber mats can be put under noisy kitchen appliances and computer printers to cut down on noise. Curtains and carpeting also help reduce indoor noise. Storm windows or double-pane windows can reduce the amount of outside noise that enters the home or workplace.
  • Don’t use several noisy machines at the same time.Try to keep television sets, stereos, and headsets low in volume. Loudness is a habit that can be broken.
  • Don’t try to drown out unwanted noise with other sounds.For example, don’t turn up the volume on your car radio or headset to drown out traffic noise or turn up the television volume while vacuuming.
  • Have your hearing checked if you are regularly exposed to loud noise at work or play.

Noise-induced hearing loss treatment

There is no cure for permanent hearing loss. One of the most obvious “treatments” for this type of hearing loss is avoiding your exposure to noise. This can prevent your hearing loss from getting worse.

There is equipment that can help you hear better. Depending on the degree of your hearing loss, you may benefit from using a hearing aid (a device you wear on your ear to magnify sound). For profound hearing loss, you may qualify for a cochlear implant. A cochlear implant is an electronic hearing device that replaces the damaged inner ear with a ray of electrodes. These electrodes are surgically implanted in your inner ear. They provide sound signals to your brain.

Living with noise-induced hearing loss

Hearing allows you to be involved with the world around you. When you begin to lose hearing, you feel disconnected. Even isolated. You have learned most of what you know by listening to parents, teachers, television, and radio. Music, the sounds of nature, and the voices of loved ones can bring you pleasure; sirens and alarms can warn you about danger, even when you are asleep.

The first way to cope with this loss is to acknowledge it. Hearing loss is not something you should hide or be ashamed of. Once you recognize it, then you can begin to deal with the loss and take action to correct it, if possible. Being proactive about hearing loss can even stop its progression (continued development), saving you from greater hearing loss.

Recently, researchers have linked hearing loss to cognitive problems and even dementia. This means that people who have hearing loss are more likely to have these conditions also. However, studies are now finding that treating hearing loss can lessen this increased risk for dementia.

Questions to ask your doctor

  • How can I recognize that I have a hearing problem?
  • Are there different types of hearing loss?
  • Aren’t I too young to have hearing loss?
  • Is there a medication that can help treat hearing loss?
  • Will I be able to hear better with a hearing aid?
  • Does my medical insurance pay for a hearing aid?

Resources