Understanding Noise-Induced Hearing Loss

Understanding Noise-Induced Hearing Loss
Cyndi Connolly
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Our ears evolved to keep us attuned to our environments, so we could hear each other and get one another’s attention, hear danger approaching, or hear a prey animal approaching that we could hunt. Since the time of the Industrial Revolution, our lived environments have featured sounds that are simply too loud for our ears to take in without being damaged. Many of our jobs involve extended exposure to loud noise, and even walking down a busy street brings the sounds of engines, sirens, and construction projects. Going to a rock and roll concert or listening to music in earbuds, common activities of enjoyment in today’s age, can easily cause permanent hearing damage. Even going to the movies can expose us to uncomfortably loud sounds.

What is Noise-Induced Hearing Loss?

Noise-induced hearing loss (NIHL) is hearing loss that is specifically caused by exposure to sound. It can be caused by sudden bursts of extremely loud sounds, or by extended exposure to sounds at levels that are not even uncomfortable. Any sounds reaching or exceeding 85 decibels A-weighted (dBA), when extended for many hours, can cause permanent hearing loss. That’s about the volume of a lawnmower.

Causes of NIHL

Common activities that include risk factors for hearing loss are shooting firearms, motorsports, listening to loud music, playing in a band or attending concerts. Work around the house involving not only lawnmowers but weed wackers, chainsaws, pressure washers, leaf blowers, and woodworking power tools will also put us at risk for hearing loss. The louder the sounds that we’re exposed to, the less time it takes them to cause hearing loss. Even frequent repeated exposure to sounds around 85 dBA can eventually cause hearing loss.

What Parts of Our Ears Are Damaged by Noise?

Our ears send sound energy to our brains by a complicated process of transferring vibrations. Sound travels through the ear canal to the eardrum, which vibrates sympathetically, transferring vibrations in turn to the three little bones of the middle ear- the malleus, incus, and stapes. These bones transfer the vibrations to fluid, which ripples through the cochlea, where tiny hair-like cells called cilia finally convert these liquid vibrations into electrical energy for the brain to interpret.

It is these cilia, inside the cochlea, which are usually the cause of hearing loss. Over time, if they are excessively stressed, they break, and no longer convert vibrations to electrical energy. There is no remedy for this; once they are broken, they do not heal.

Excessive bursts of loud sound, like explosions or gunshots, can damage the eardrum itself or the bones of the middle ear. This damage will result in immediate hearing loss.

Who Is at Risk?

NIHL affects people of all ages, with some studies suggesting that as many as 17% of teenagers already experience some amount of hearing loss in one or both ears. Life these days is so full of loud sounds, NIHL can seem unavoidable, but there are things we can do to protect against it.

Preventing NIHL

Always carry a pair of earplugs when you leave the house. You never know when you might encounter a scenario involving sustained loud sounds, so be prepared. There are now cell phone apps that will measure dBA, many of them free, which you can use to determine if the sounds around you are at hazardous levels.If for whatever reason you aren’t able to wear earplugs or if you find the volume level to be uncomfortable even with earplugs in, move away from the sound. Always remember, whatever is going on is not worth the permanent loss of your hearing! If you’re engaged in an especially loud activity, everyday earplugs might not even be enough. For, say, visiting a shooting range or using a masonry nailer, always wear earmuffs with extra protection.

Be sure to get your hearing tested at regular intervals. It’s best to discover hearing loss early so that you can make whatever lifestyle changes might be necessary to prevent further damage. The rates of NIHL are rising, and it is no laughing matter. A little caution will go a long way in making sure you can enjoy the pleasures of the auditory environment over the course of a long life!