Tag Archive: hearing damage

Bicyclists at risk of hearing loss

By Daniel Fink, MD, Chair, The Quiet Coalition

A new study shows that bicycle riders may be at risk of hearing loss, and the culprit is wind noise. The study by Dr. Michael Seidman, an ear specialist who also is a bicycle rider, measured sound levels in a wind tunnel, finding that under many conditions noise level were high enough to cause auditory damage. The measurements need to be replicated on the road, which is a more challenging endeavor.

To me, the important thing to note is how Dr. Seidman conceived of the study: he was out riding with his brother and found that they had to shout at each other to be heard over the wind noise. He states that “OSHA, the Occupational Safety and Health Administration, says you can be exposed to 85dB of loudness for an eight-hour time period at work. But that does cause noise-induced hearing loss — we know that it does,” he said. “So anything over 85dB causes noise-induced hearing loss.”

I wrote about the 85 dB (actually A-weighted decibels, or dBA) occupational standard in the American Journal of Public Health, in which I noted that 85 dBA “is not a safe noise exposure level for the public.” Humans have difficulty understanding speech if the ambient noise is above 75 decibels. (Technically, those are A-weighted decibels, or dBA. That information is in Figure D-1 in the 1974 EPA “noise levels” monograph.) And Flamme et al. discussed the fact that the auditory injury threshold is only 75-78 dBA.

So, as Dr. Seidman realized, if it sounds too loud, it IS too loud. You don’t need a sound meter to know that. If you have to strain to speak or to hear conversation, the ambient noise is above 75 dBA and your hearing is being damaged.

What should bicyclists do to protect their hearing? Earplugs are an obvious choice, but Dr. Seidman says that they are illogical because “It’s not a good idea to wear earplugs when you ride — you can’t be aware of your surroundings.” He suggests that helmet design could address wind noise (but apparently isn’t offered at this time), but adds that accessories are available, such as AirStreamz Pro Cycling Wind Noise Reducer  by Cat-Ears, which are attached to eyeglasses or helmet straps and help to deflect noise.

Dr. Daniel Fink is a leading noise activist based in the Los Angeles area. He serves on the board of the American Tinnitus Association, is the interim chair of Quiet Communities’s Health Advisory Council, and is the founding chair of The Quiet Coalition, an organization of science, health, and legal professionals concerned about the impacts of noise on health, environment, learning, productivity, and quality of life in America.

Is nothing safe?

They look so innocent…

Experts Warn Popping Balloons Can Lead To Permanent Hearing Loss. Arrianne Del Rosario, Tech Times, writes about an experiment conducted by researchers at the University of Alberta “to find out how noise from bursting balloons can impact hearing,” and the results were stunning.  The researchers “measured the noise levels from popping balloons in three different ways: poking them with a pin, blowing them with air until they burst, and crushing them until they exploded.”  The loudest bang came from blowing up a balloon with air until it popped.  When it did, it was recorded at almost 168 decibels, “4 decibels louder than a high-powered, 12-gauge shotgun.”

It can’t be that bad, it’s just a balloon, right?  Wrong.  Del Rosario notes that the Canadian Centre for Occupational Health and Safety recommends that “the maximum impulse level should never go beyond 140 decibels.”  She adds that “[c]onstant exposure to noise, even as low as 85 decibels — for example, the noise from cars honking their horns in a city traffic — can make a person vulnerable to hearing loss.”

Del Rosario is right that damage to hearing can occur well under 140 decibles, but wrong to imply that damage only occurs at 85 decibels or higher.  85 decibels is the industrial-strength occupational noise exposure standard. Auditory damage can begin at only 75-78 decibels.  The only evidence-based safe noise exposure level is the EPA’s 70 decibel time weighted average for 24 hours.  Cautions noted noise activist Dr. Daniel Fink, “If it sounds too loud, it is too loud.  Hearing is an important social sense, and once cochlear hair cells and auditory synaptic junctions are damaged, they are gone forever.”

Whatever the decibel reading, the problem is that each exposure to loud noise leaves a mark.  As one of the researchers, Bill Hodgetts, advised:

Hearing loss is insidious — every loud noise that occurs has a potential lifelong impact. We want people to be mindful of hearing damage over a lifetime, because once you get to the back end of life, no hearing aid is as good as the once healthy built-in system in your inner ear.

This is fascinating:

crash-photo

Mercedes-Benz E-Class will blast pink noise at you just before an accident, to protect your ears.  That’s right, in an effort to cut down on “hearing damage caused by the deafening crunch of a car crash,” Mercedes-Benz is going to “blast[] pink noise through the stereo when you’re about to hit something.”  What will the pink noise do?  It will “trigger a fascinating physical response…known as the acoustic reflex, or stapedius reflex – an involuntary muscle contraction in the middle ear that effectively dampens the vibrational energy that’s transferred to the cochlea.”  Essentially, the reflex action will reflect some of the noise from a crash back through the ear drum, thus avoiding the inner ear.  Click the link to learn more.

 

 

 

Can’t Hear in Noisy Places? There a reason for that:

Melinda Beck, writing for the Wall Street Journal, examines hidden hearing loss, a condition where people have trouble understanding conversations in noisy situations.  Beck looks at how it differs from traditional hearing damage, reporting that:

[T]here’s growing evidence that the causes of problems processing speech amid noise are different than the causes of problems hearing sound. Scientists believe exposure to loud noises can erode the brain’s ability to listen selectively and decode words, without causing traditional hearing damage. Difficulty understanding speech amid noise can set in long before traditional hearing loss.

The researchers at Massachusetts Eye and Ear Infirmary who discovered hidden hearing loss in mice in 2009 have recently shown that damage occurs in humans as well.  “Exactly how such damage, called cochlear synaptopathy, compromises the ability to understand speech amid noise isn’t fully understood,” writes Beck, but “researchers think cochlear synaptopathy may help explain tinnitus, the persistent buzzing or ringing some people hear, as well as hyperacusis, which is an increased sensitivity to unpleasant sounds such as a baby crying or a siren.”

Apparently many people who may have hidden hearing loss also have traditional hearing loss.  Sadly, there isn’t enough information yet for hidden hearing loss to be part of routine diagnosis of hearing problems, but the research continues.  Until then, audiologists suggest patients who have speech-in-noise difficulties consider hearing aids and other assistive listening devices.

Thanks to Charles Shamoon for the link.