conley6.gif (2529 bytes)


Now Hear This
Amp up your noise knowledge to help prevent hearing loss.


Sept. 2018

Studies have shown that, along with age, exposure to noise is the leading cause of hearing loss in America. Up to 15 percent of children have permanent hearing loss caused by everyday noise. To take the right steps to protect our ears, we must first understand what is considered a harmful level of noise.

When sound waves enter the ear, they cause the eardrum to vibrate. That vibration is transmitted to the cochlea in the inner ear. Fluid carries the waves to rows of hair cells called stereocilia, which then send electrical impulses through the auditory nerve to the brain. There, they are interpreted as the various sounds we hear. Excessive noise can essentially shear off the stereocilia, leaving them unable to discharge the electrical impulses as they should, which can result in hearing loss.

The volume of the sounds around us is measured in decibels (dB). The level at which noise can cause permanent hearing loss begins at about 85 dB (think your snowblower), but prolonged exposure to sounds at 75 dB (a loud TV or the average vacuum cleaner) can also bring about hearing loss.

Most of us are protected in our work environments. Even so, according to the Occupational Safety and Health Administration (OSHA), 22 million workers are exposed to damaging noise levels. Last year alone, U.S. businesses were fined more than $1.5 million for not properly protecting their workers from damaging noise. OSHA regulations state that all personnel must wear hearing protectors when exposed to noice levels of 90 dBA (the weighted measurement for how human ears perceive sound) or greater in an 8-hour work day. If the level rises above 105 decibels, double protectors are required.

At home, however, we are on our own in protecting ourselves from continued exposure to damaging noise levels, says Tricia Chirillo, director of the UW-Milwaukee Audiology Group. “This is known as noise-induced hearing loss (NIHL), which is hearing loss due to the cumulative effects of noise on our ears over time,” says Chirillo. “The severity of it depends on the level of noise exposure and the length of time that you are exposed. You can experience temporary hearing loss from being overexposed to loud noise. There is also acoustic trauma, a type of noise-induced hearing loss that can happen after a one-time exposure to a very loud sound, [such as] an explosion or blast.”

Signs of overexposure to noise include tinnitus (a ringing sound or buzzing sound in the ears) or a sensation of fullness or pressure in the ear canal when you leave a noisy situation. “Another sign is that speech and other noises sound dull or muffled after you’re exposed to loud noise, almost as if you are wearing earplugs ... or if the noise causes pain in your ears,” says Chirillo.

The best defense against NIHL is to use protection like ear plugs or ear muffs whenever you are exposed to loud noise, even if the exposure is for a short period of time.  “Using a chain saw, lawn mower, shop vac, power tools [or] leaf blower at home, even [during] short-term exposures can lead to long term damage,” says Chirillo. “Turn down the volume or move away from sources of loud noise whenever possible. Avoid or limit loud noise exposure.”

Chirillo also notes that to protect children’s hearing, parents should limit the length of time kids use earbuds or earphones and the volume level of what they’re listening to. “They should be able to hear others talk while using earphones — and others should not be able to hear their music,” she explains. “You should also protect their ears from noise when attending events such as fireworks, monster truck shows, concerts and so forth. Avoid noisy toys, some of which can be very loud if kids put the speaker up next to their ear. And turn down loud music while in the car and other places — especially if the voices of others can’t be heard over the volume of the music.” 


This story ran in the Sept. 2018 issue of: