(Last updated Nov 21, 2019)

Noise-Induced Hearing Loss [Causes, Symptoms, Treatment]

decibel loudness level graphic
 
Noise-induced hearing loss is becoming a serious problem in the United States.

According to the Centers for Disease Control, 24 percent of adults have noise-induced hearing loss by age 60.

Even more alarming, one study of teenagers found that around 16 percent have signs of noise-induced hearing loss.

These statistics are concerning when you realize that this kind of hearing loss is permanent.

It’s sad to realize that many teenagers and adults are risking a lifelong decrease in their ability to enjoy the meaningful sounds of life.

In this article, we’ll explain the causes and symptoms of noise-induced hearing loss, along with prevention and treatment options.

Quick Navigation

What is Noise-Induced Hearing Loss?

Noise-induced hearing loss is hearing loss caused by loud noise.

Let’s first define what we mean by “noise”.

Usually, in everyday life, we refer to sounds that we don’t like as “noise”.

Like traffic noise, or your office cubicle neighbor’s annoying radio station.

In the hearing health world, “noise” refers to sounds that are too loud.

So, the sound of nails on a chalkboard might be annoying, but it isn’t “noise” when we are talking about “noise-induced hearing loss”.

On the other hand, you might love rock music, but it’s considered “noise” to hearing care professionals if it’s blasting away at 100 decibels.

You see, your ears are built to handle a lifetime of listening to sounds in the natural world that our biological ancestors inhabited thousands of years ago.

That is, your ears are well-equipped to handle the sound environment in places like caves.

I’m pretty sure that a teenager thousands of years ago wasn’t blasting rock music at 100 decibels in the caves.

Nowadays, our ears are frequently assaulted by loud sounds in workplaces, restaurants, and concerts.

Your ears aren’t biologically equipped to handle all of that loud sound.

Therefore, being around loud sounds can, over time, damage your hearing.

Symptoms of Noise-Induced Hearing Loss

If you suspect you have a noise-induced hearing loss, you might experience some of these symptoms:

  • You have a hard time understanding people
  • Things sound muffled to you
  • You have ringing in the ears (tinnitus)
  • You struggle to hear in background noise

The first step to determine whether or not you have a noise-induced hearing loss is to get a hearing test.

The results of your hearing test will be plotted on an audiogram, like the one shown below.

Noise notch audiogram indicative of noise induced hearing loss

Audiogram showing a noise-notch that is typically indicative of noise-induced hearing loss

Often times, your audiogram will show a noise notch, (shown above) or an area of worse hearing around 4000 Hz that is common in people with noise-induced hearing loss.

Note: The absence of this notch doesn’t mean that your hearing loss isn’t related to noise exposure.

Usually, the hearing test results will be clear and it’ll be obvious you have a noise-induced hearing loss.

However, in some cases, a basic hearing test may not be enough to show the damage to your hearing from noise, and you may actually even be told that you don’t have a hearing loss.

This is called “hidden hearing loss” – when a basic hearing test seems to show normal hearing sensitivity but you report problems understanding people in background noise.

So- if you have a history of spending time in noisy environments, your hearing care provider may want to add some special tests to detect damage that could be missed by a basic hearing test.

These additional tests include:

  • Measurements of how well you understand speech in noise
  • Otoacoustic emissions, which are physiological measures of how your cochlea (inner ear) responds to sound

What about temporary noise-induced hearing loss?

Sometimes, after being around loud sounds like a rock concert or a firearm shot, you may perceive a temporary decrease in your hearing that seems to return to normal after a while.

This is called temporary threshold shift.

However, even if your hearing seems to return to normal, you may still have lasting damage to the nerve pathway that sends sounds from your inner ear to the brain.

This lasting damage could mean that your nerves have more problems carrying accurate information about sound to your brain, and you experience more difficulties understanding people in noisy places.

Causes of Noise-Induced Hearing Loss

You can get noise-induced hearing loss from a single loud blast, like an explosion, or from being around loud sounds over time.

If you’re hearing loss is a result of blast or explosion, you may have a conductive hearing loss, if the blast caused trauma to your eardrum or middle ear bones.

Most people with noise-induced hearing loss have damage to their ears that wasn’t caused by a single traumatic event, but from being around noise over time.

If your hearing loss is a result of long term exposure to noise, you likely have a sensorineural hearing loss (inner ear damage).

Whether you have damage to ears from noise depends on two things: how loud the noise is, and how long you were around the noise.

The louder that a sound gets, the less time you can spend listening to it before you have damage to your ears.

In the United States, the guidelines for “how loud is too loud” are set by two organizations: the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA).

NIOSH guidelines are based on research into how much noise exposure over time is safe for most people.

OSHA guidelines are enforced by laws that require industries like construction and mining to have hearing conservation programs. They are a compromise between business and public health interests, so they are less stringent than NIOSH guidelines.

These guidelines assume that people are exposed to these sound levels at work for 8 hours a day, over a 40-year working lifetime.

The guidelines don’t take into account time that you might spend outside of work in noisy hobbies, nor your individual susceptibility to noise-induced hearing loss.

Therefore, limiting your noise exposure to these levels may not completely protect you from noise-induced hearing loss. However, they are a good place to start.

Here’s a handy chart of the basic guidelines from OSHA and NIOSH for how loud is safe for different time durations.

Maximum exposure duration (per day) OSHA safe level NIOSH safe level
8 hours 90 dBA 85 dBA
4 hours 95 dBA 88 dBA
2 hours 100 dBA 91 dBA

 
“dBA” stands for “A-weighted decibels” – a special way of measuring sound that takes into account the ear’s sensitivity to different pitches.

Basically, you should be wary of any sounds above 85 dBA.

Below is a graphic of common sounds and their associated noise levels

Noise levels of common sounds

Sound level source: https://www.asha.org/public/hearing/Loud-Noise-Dangers/

How Loud Noise Damages Hearing

Biologically, there are four different ways that noise can damage your ears:

  1. Acute acoustic trauma: This can be caused by a blast that is so loud that the sound pressure creates a hole in your eardrum, damages your middle ear bones, ruptures parts of your inner ear (cochlea), or causes a concussion that damages auditory portions of your brain.
  2. Damage to the nerve connections (synapses) between the auditory nerve and cochlea: Noise exposure can cause these connections to weaken or stop working. When this happens, you may still be able to hear soft sounds and respond normally to a basic hearing test, but have problems understanding speech in noisy environments because the nerves have trouble coding sounds correctly.
  3. Metabolic changes over time to your cochlea: Noise causes an increase of chemicals in your ear that can cause cells that are important for hearing to die.
  4. Being around noise is psychologically stressful: This may activate brain circuits that make your ears more susceptible to noise, or cause problems like high blood pressure that can lead to ear damage.

Research has shown that your ears are more susceptible to harm from noise if you smoke, have diabetes, use aminoglycoside antibiotics or platinum chemotherapy drugs, have exposure to certain chemical agents on the job, or already have sensorineural hearing loss.

Genetics may also play a role in how easily your ears are damaged.

Treatment Options for Noise-Induced Hearing Loss

If you have noise-induced hearing loss, the main treatment is to get hearing aids.

Because people with noise-induced hearing loss often have a lot of problems understanding people in background noise, you’ll want to get hearing aids with directional microphones and noise-reduction technology.

Directional microphones on hearing aids help to separate sounds in the environment so that the hearing aids can boost the level of the speech that you want to hear, and reduce the level of interfering noise.

Noise reduction technology dampens the noise in the environment, so that all of the background sounds in a noisy place like a restaurant do not bother you as much.

You may also consider these other treatment options:

  • See a specialist in tinnitus treatment, if you have tinnitus (ringing in the ears).
  • Using special devices like TV Ears for the television.
  • Learn to use good communication strategies that make listening easier.

In the future, you may be able to take drugs to help prevent noise-induced hearing loss. There are currently clinical trials underway to see if taking antioxidants could help protect against damage.

Prevention of Noise-Induced Hearing Loss

To prevent noise-induced hearing loss, you need to limit the time that you spend around sounds that are .

A quick way to know if a sound “is too loud” is to ask yourself these questions:

  • Can you understand other people who are three feet away?
  • Do you need to raise your voice in order to be heard?
  • Do you have ringing in your ears (tinnitus) or are sounds muffled after you walk away?

You can also use tools available to measure sound loudness. You want to avoid sounds that are above 85 dBA.

If you have an Apple Watch, you can turn on noise monitoring and get notifications when you are in a loud environment.

If you have a smartphone you can use a sound level meter app (example below) to measure the sound level around you.

Sound level app

Screen recording of a popular (free) sound level app for smartphones

If you prefer not to use your smartphone, there are inexpensive sound level meters available online.

Should you use an app or sound level meter, you want to measure sounds in dBA.

Recall from our previous discussion that “dBA” stands for “A-weighted decibels” – a special way of measuring sound that takes into account the ear’s sensitivity to different pitches.

You don’t need to worry about the technical details. Just make sure that your device is set to dBA, and not other weighting options that you may find, like dBC or dBB.

If you are around sound that is louder than 85 dBA, than you can prevent hearing loss by walking away from it, turning down the sound, or wearing hearing protection.

Hearing protection can take the form of disposable foam or silicone earplugs, custom-made earplugs, or earmuffs.

The most important thing about hearing protection is that you wear it consistently and correctly.

Some people find custom-made earplugs that are made from an impression of your ears to be more comfortable – you can ask your hearing care professional to make you a set.

Custom-made earplugs are also often easier to put in your ears than other kinds of earplugs.

These earplugs can be made with special filters that allow you to still hear soft sounds around you while still dampening loud sounds.

Custom earplugs for musicians should contain filters that make sure that the sound quality of music does not change while wearing the earplugs.

If you do use foam earplugs, remember that you need to roll, pull, and hold:

  1. Roll the foam between your fingers to ensure that the foam is compressed into a tight cylinder.
  2. Pull your ear back with your other hand to straighten your ear canal and put the plug into your ear.
  3. Hold the plug in your ear with the tip of your finger until the foam expands to fill your ear canal.

There’s one particular prevention tip I’d like to mention, given the alarming statistic that 12 percent of kids have hearing loss from listening to loud music.

Kids (and adults) like to listen to personal music players throughout the day.

A tune may be a welcome bit of relaxation during a busy day.

I see lots of adults using music players to block out traffic noise during their commutes on public transportation.

However, those devices shouldn’t be so loud that you can’t carry on a brief conversation with someone next to you.

In fact, if you are able to block out the sounds around you completely, chances are that the music player is too loud.

You can adjust the maximum volume of many of these devices to 80 dB or less to minimize your risk of hearing loss – check your user manual for details.

Conclusion

You may be at risk for noise-induced hearing loss because you work in a noisy job or have loud hobbies.

If you are noticing problems hearing, a hearing care professional can do a hearing test and talk with you about your treatment options.

Whether or not you already have noise-induced hearing loss, you should protect your hearing to prevent further damage to your ears.

Jeff Hall Jeff Hall Jeff is a California licensed hearing aid dispenser and the President of ZipHearing- one of the largest discount hearing aid suppliers in the United States. Jeff lives in San Diego, CA with his wife and young daughter. You can learn more about hearing aids and watch Jeff on ZipHearing's Youtube channel.

You might also be interested in:

Leave a comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.