Harvard College Health Advocacy Program

hear today gone tomorrow2

For Whom the Bells Toll

By on January 19, 2014

Bells you say?

Church bells? Hemingway? Cowbell?

No.  By bells, I mean tinnitus.  The psychological bells of hell.

Tinnitus is the medical term for ringing in the ears.  The most common cause of tinnitus is exposure to loud noise over long  periods of time.  In today’s day and age, that sort of noise exposure is a lot more common than you would think.  Meaning, tinnitus and other associated hearing disorders (early onset of deafness and hyperacusis, for example), could be just as much of a health threat as diabetes, hypertension, and obesity.

Just think.  Deafness or tinnitus at age 30 could become as prevalent a public health concern among Americans as obesity (Two-thirds of Americans are overweight or obese).   You have a 66.6 percent chance of having constant ringing in your ears before you buy your first house.

“Why is this the case?” you may ask.

The world is getting louder.  Since the Industrial Revolution, machines have provided the constant hum in the background to which we have become accustomed.  The Textile Revolution, the rise of the railway, the attack of the automobile, and now, airplanes, computers, phones, stereo systems and iPods, to name a few, have amplified our sonic world.  Just a day spent touring New York City, which deploys a nearly 90 decibel burst, is enough to set your ears on edge.

Several researchers have conducted longitudinal and cross sectional survey studies of people in noisy environments to see how the noise affected them.  Residents of the Big Apple who took the subway to work and back daily, had a higher share of people with tinnitus and hearing damage than those who did not commute by train.   Additionally, several musicians and celebrities have reported having tinnitus (though I suspect every musician who tours in huge venues has some level of hearing damage).  To name a few who have reported their ringing: Pete Townshend of The Who, talk show host David Letterman, Captain Kirk’s William Shatner, One Direction heartthrob Louis Tomlinson, and U2’s Bono.  Here’s a more comprehensive list.

But even for those of us who are not rock stars, the threat of permanent hearing damage looms near, as near as your jacket pocket. Studies have shown that those who listen to MP3-players at loud volumes and long durations are twice as likely to have hearing damage.   A conservative measure of  unsafe MP3-player combinations is in the table below.

100% of maximum volume for 6 minutes or more day
90% of maximum volume for 25 minutes or more per day
80% of maximum volume for a total of  more than 1.5 hours per day
70% of maximum volume for a total of more than 6 hours per day

In fact, 100 dB of noise for just minutes can damage your ears.  In perspective, 100 dB is about 90 percent of an iPod’s maximum volume.  On the subway, walking through traffic, or mowing the lawn, you’d be surprised at how effortlessly the volume meter creeps up to 90 percent of the max.

So what exactly happens to cause the hearing damage? Understanding the answer to this question requires understanding the biology of the inner ear.  In the healthy inner ear, tiny neurons called hair cells vibrate with the mechanical energy created from sound.  Think of blades of grass moving in the wind.  One theory is, the stronger the wind, the more likely the blades will break.  The louder the noise, the more likely the physical force of the sound will deform the tiny neurons.  In mammals, once these neurons are flattened, they cannot regenerate into healthy cells again.

haircells

 

Another theory is that hair cells become much more metabolically active when responding to louder noises, resulting in the production of more biological toxins, natural byproducts of metabolism.   Unable to buffer such a high level of toxins, the hair cells die.

Regardless of which concept is most biologically accurate, the fact still remains that loud noises for long durations cause hearing damage.  Even instantaneous bursts of extremely loud noise can cause permanent damage.  This in fact is most common for veterans of war, exposed to hauntingly loud gun shots of battle.  And unexpected from the shambles of the Boston Marathon Bombings were patients complaining of all sorts of hearing damage.

So, what’s anyone doing about it?  That’s just the thing.  No one is doing enough.  New York City, however, might be on to something.  Launching a public health campaign to plaster public service announcements cautioning against hearing damage from unsafe iPod listening, the city is making steps towards preventing the hearing damage epidemic.  

The rest of us should take NYC’s lead.  Los Angeles, Boston, where are you?  There are hordes of people, mostly “invincible” young adults, who aren’t convinced that this is a problem, and probably will not be until they hear the ringing every day.  By that time, public health costs for yet another chronic disease will start to soar.  If doctors thought that neurasthenia was a problem, well, here comes the 21st century analog.  Noise and music induced hearing damage teeters on the brink of an epidemic, but will Americans hear the not-so-silent cry before its too late?

–Posted by Gita Bhattacharya, ’16

 

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Harvard College Health Advocacy Program's mission is to connect Boston youth and Harvard undergraduates with health education and wellness resources so that they may actively pursue a healthy lifestyle. To achieve this goal off-campus, HAP's mentors work with elementary, middle, and high school students to teach hands-on health curricula covering topics such as nutrition, exercise, food advertising, and music and noise induced hearing damage in youth. On-campus, HAP promotes our mission by hosting health-themed study breaks, group exercise socials, and resourceful cooking seminars. We believe bringing together undergraduates passionate about healthy living will enable us to improve the health of the communities in which we live.

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