Hidden Hearing Loss

Four in 10 UK adults unknowingly endanger their hearing on a daily basis

Photo credit: Gary J. Wood licensed under CC BY-SA 2.0

by Daniel Fink, MD, Chair, The Quiet Coalition

This report states that 40% of adults in the United Kingdom (England, Scotland, Wales) unknowingly endanger their hearing on a daily basis.

This finding fits neatly with Dr. Gregory A. Flamme’s report that 70% of U.S. adults get total noise doses exceeding safe limits and Dr. Richard Neitzel’s similar finding in a Swedish population.

This isn’t rocket science–noise exposure for the ear is like sun exposure for the skin. If you don’t want deep wrinkles, age spots, and skin cancers when you get older, wear a hat, long sleeves, sunscreen, and avoid the sun.

If you don’t want hearing aids when you get older, avoid noise exposure.

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.

Will earbuds ruin my hearing?

Photo credit: Marcus Quigmire licensed under CC BY-SA 2.0

by Daniel Fink, MD, Chair, The Quiet Coalition

The headline for this article in Time magazine is “Will earbuds ruin my hearing?” The short answer is that it’s not the earbuds or headphones that damage hearing, but the noise emanating from them. The longer answer follows.

The article widely cites Dr. Robert Dobie at the University of Texas Health Science Center at San Antonio who says that earbud use isn’t a problem.

It also cites Harvard researcher Dr. M. Charles Liberman, who, with Dr. Sharon Kujawa, discovered the phenomenon now known as hidden hearing loss. This is damage to nerve junctions (synapses) in the ear, called hidden because it is not detected by standard hearing tests.

Dr. Liberman says that earbud use might be a problem.

Dr. Dobie’s assertion that earbud use isn’t a problem sounds just like the doctors in the 1950s and 1960s who insisted that smoking cigarettes wasn’t harmful to health. We now know differently.

My conclusion is that noise causes hearing loss. The human ear was not designed to withstand loud noise exposure because such a tolerance offered no evolutionary advantage. As I wrote in the January 2017 American Journal of Public Health, the only evidence-based safe noise exposure level to prevent hearing loss is 70 decibels time-weighted average for a day. I further explained, in a requested blog post for AJPH, that the real safe noise exposure level is probably lower than that.

We know, from decades of research on occupational noise exposure that led to the occupational safety criteria for noise exposure, from the work of Liberman and colleagues, and from hundreds or thousands of studies showing that noise damages hearing in animals and humans with the cellular and sub-cellular mechanisms of how this occurs now precisely understood that noise causes hearing loss.

If you believe Dr. Dobie, continue to listen to your personal music player using earbuds or headphones.

If you don’t want hearing aids when you are older (and I don’t think hearing loss is part of normal aging, as I said at the 12th Congress of the International Commission on the Biological Effects of Noise in Zürich in June 2017) my advice is not to use earbuds.

Your ears are like your eyes or your knees. God only gave you two of them. Protect them and keep them safe and working well your entire life.

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.

Groundbreaking research proves restaurants are too noisy

by Daniel Fink, MD, Chair, The Quiet Coalition

New York based researcher Greg Scott presented a groundbreaking study Tuesday, December 5th, at the 174th meeting of the Acoustical Society of America in New Orleans, Louisiana. Mr. Scott reported actual decibel measurements, obtained using the free IOS SoundPrint app he developed, on almost 2,000 restaurants and bars in New York City. The average sound level was 78 A-weighted decibels (dBA) in restaurants, and 81 dBA in bars.

Even people with normal hearing can’t understand speech if the ambient noise is above 75 dBA, which is also the auditory injury threshold (the noise level at which hearing damage begins). People with moderate hearing loss–25-40 dB decrement in hearing–need ambient noise lower than 60 dBA to be able to understand speech.

The SoundPrint app is easy to use and can help find quieter restaurants and the rare quiet bar. But it is clear to me–as I stated in my own talk, which preceded Greg’s–that high ambient noise in restaurants and retail stores is a disability rights issue for people with hearing loss, tinnitus, and hyperacusis. The Americans with Disabilities Act (ADA) guarantees people with disabilities the full and equal enjoyment of places of public accommodation, which are basically any facility open to the public. If one can’t hear in a noisy place, one’s ADA rights are being violated. It is likely that legal action will be required to make these places quieter.

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.

Coping with hearing loss and noisy restaurants is not a game

by Daniel Fink, MD, Chair, The Quiet Coalition

This report from CNN discusses a novel strategy to help people with hearing loss understand speech: a game to train the brain to process speech better.

This is a widely known but poorly understood problem–sometimes called the “Speech in Noise problem”–with people with hearing loss, but it can also affect people with normal or adequate hearing as tested by standard hearing tests (“pure tone audiometry”) who nonetheless can have problems understanding speech.

The problem is worse for those with hearing aids, which is probably why up to 40% of people with hearing aids don’t use them–they just don’t help understand speech in everyday situations. As hearing loss blogger Shari Eberts has written, hearing aids just are not like eyeglasses.

Some research supports a central cause for this, i.e., deficiencies in brain processing of auditory signals as people age. Other research puts the problem in the periphery, i.e., the ear. And the research on hidden hearing loss puts the problem in between, in the nerves connecting the ear to the brain. Most likely the explanation involves all three.

Even though the computer game reported in this story may eventually help people who struggle to understand speech, dealing with hearing loss and noisy restaurants isn’t a game.

The real answer isn’t brain training. It’s quieter restaurants, stores, and other public places.

Quieter indoor places will not only help those who already have hearing loss understand speech, they will prevent hearing loss in those still with good hearing.

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.

When “good news” is bad news

Daniel Fink, MD, Chair, The Quiet Coalition

This article in JAMA Otolaryngology about hearing loss in young people age 12-19 is getting press as good news. Researchers at the University of California (both the Los Angeles and San Francisco medical schools) analyzed audiometric test data on young Americans from the National Center for Health Statistics collected by National Health and Nutrition Survey (NHANES). The researchers concluded that the prevalence of hearing loss as measured by standard pure tone audiometry had not increased despite wider use of headphones and earbuds to listen to personal music players.

We don’t think this is good news at all.

First, the researchers state that the prevalence of hearing loss in 2009-2010 is 15.2%. Hearing only worsens with age, so based on the data, it appears that about one-sixth of young people are likely to have profound hearing loss in mid-to-late life. If they were losing their vision instead, would anyone think this was good news?

Second, the subjects hearing was assessed by standard pure-tone audiometry. These traditional tests do not detect hidden hearing loss, which indicates nerve damage (synaptopathy) caused by noise exposure. Only techniques that are now considered research techniques will detect this early auditory damage.

Third, the authors note that there was increased risk of hearing loss in racial/ethnic minorities and those from low socioeconomic backgrounds. Isn’t hearing health an issue for this group of Americans too?

Finally, the researchers discuss the many limitations of this type of data analysis, which means that no definite conclusions can be drawn from this study.

In the end, the article generated a lot of “good news” headlines and in doing so has done a disservice to all young people, because those headlines and the cursory reports that followed downplay the dangers of increased headphone and earbud use. This is particularly galling and irresponsible when one recognizes that noise-induced hearing loss is 100% preventable.

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.

New drug may prevent hearing loss after noise exposure

By Daniel Fink, MD, Chair, The Quiet Coalition

For many years, a body of research has shown that chemicals with antioxidant properties might prevent or reduce hearing loss after noise exposure. In animals, noise exposure reduces levels of a chemical called glutathione peroxidase 1 (a naturally occurring enzyme). A recent report in the British journal The Lancet looks at how a similar chemical, ebselen, works in helping to reduce “both temporary and permanent noise-induced hearing loss in preclinical studies.”

It appears to work quite well.

Of course, we at The Quiet Coalition think it’s better just to avoid loud noise exposure, which is 100% safe and effective at preventing hearing loss. That said, the experimental protocol raises interesting questions about research ethics. Namely, the study tested the efficacy of different doses of ebselen after the subjects, healthy adults aged 18–31 years, were exposed to loud sound. The measure of ebselen’s success was the prevention of a phenomenon called temporary threshold shift (TTS), more completely noise-induced temporary threshold shift (NITTS). This audiometric measure has been used for decades to measure the impact of noise on humans.

Unfortunately, recent research, beginning with a 2009 report and updated last year describes a phenomenon called “hidden hearing loss,” a synaptopathy (injury to the synapses in the cochlea) caused by noise exposure. Hidden hearing loss is called that because it is not detected by standard audiometric techniques. Hidden hearing loss is the likely cause of being unable to follow one conversation among many in a noisy environment, or having a normal or near-normal audiogram but still having difficulty understanding speech.

Many experts think that there is no temporary auditory damage. That is, TTS is a real phenomenon but the use of the word “temporary” is misleading because if TTS occurs then it is likely that permanent auditory damage has also occurred.

In this study, healthy young adults were exposed to noise levels loud enough and long enough to cause TTS, likely indicating permanent auditory damage. Some of the subjects were given large enough doses of the experimental drug ebselen to prevent TTS from occurring, but whether the drug would or wouldn’t work, and at what dosage, wasn’t known when the study began. Simply put, the study exposed all subjects to the threat of auditory damage, and most likely caused auditory damage in the subjects who received the placebo or didn’t get a high enough dose of the experimental drug.

All research protocols in the U.S. must pass review by an Institutional Review Board (IRB) which must make certain that steps are taken to prevent harm to research subjects.. Under the Helsinki Declaration of the World Medical Association, and in the United States under what is called the federal “Common Rule” (45 CFR §46 et seq.), human subjects must be protected. If there is a risk of permanent auditory damage when the phenomenon of TTS is observed–and Drs. Liberman and colleagues certainly think that temporary auditory changes denote permanent auditory damage–we think the IRB should have done more to protect the subjects from any possibility of harm.

How could a study that exposes young people to noise levels loud and long enough to cause TTS pass IRB review? We hope the federal Office for Human Research Protections will let us know.

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.

New explanation for why older people can’t hear in noisy environments

Photo credit: Filipe Fortes licensed under CC BY-SA 2.0

By Daniel Fink, MD, Chair, The Quiet Coalition

There are already several explanations about why middle-aged and older people can’t understand speech in noisy environments. One may just be high-frequency hearing loss caused by noise, which makes it hard to hear the higher-pitched consonant sounds (F, S, SH, T, V) that allow us to differentiate similar sounding words (Fear, Sear, Shear, Tear, Veer). (See the graph in this CDC Vital Signs Issue.) Another reason may be a phenomenon called “hidden hearing loss,” which is caused by noise damage to nerve junctions (synapses) in the inner ear.

And now a new report indicates that there may also be a brain or central processing problem. A study conducted at the Max Planck Institute in Germany, “analyzed what happens in the brain when older adults have trouble listening in loud environments.”  The researchers “monitored the brains of 20 younger adults ages 18 to 31, and 20 older adults in their 60s and 70s, during a listening task” in which constant background noise was played while participants were told to focus on certain targeted sounds.

What the researchers found was that “the younger adults were able to zero in on the target signals while filtering out the irrelevant noise,” but the older participants had “a harder time tuning out the background noise.” What remained unclear was whether the “degradation of the ear’s ability to hear actually leads to a decline in the brain’s ability to filter out noise and hear a single sound,” or whether “the brain’s listening ability erodes independently of any changes going on in the ear.”

As for why older people have a difficult time understanding speech in noisy environments, it most likely is that all three factors occur to varying degrees in various individuals. But one thing is certain, preventing hearing loss is simple: avoid loud noise. And improving the ability of people young and old to follow conversations is also simple: turn down the volume in indoor places.

Link via the UK Noise Association.

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.

 

Revisiting the routine audiological test

By Daniel Fink, MD, Chair, The Quiet Coalition

An audiology examination involves examination of the ear to inspect the ear drum, and then tests based on the patient’s complaints. Routine audiology testing includes pure tone audiometry, i.e., can the patient hear sound at different standard frequencies at different volumes? The recording of these responses is graphed into an audiogram:

Image credit: Courtesy of Dr. Stephane Maison

Tests of speech comprehension can also be performed.  But more detailed tests, such as DPOAE (Distortion Product Oto-Acoustic Emissions), and BAER (Brainstem Auditory Evoked Responses) are not routinely done. They are reserved to further investigate suspected problems, or used as research techniques.

But none of these tests can detect the phenomenon of “hidden hearing loss,” a synaptopathy caused by noise damage to slow response nerves and nerve junctions in the cochlea.

Dr. Stephane Maison, a leading researcher at Harvard Medical School and the Eaton-Peabody laboratory at the Massachusetts Eye & Ear Infirmary, recently published two important papers. The first, Toward a Differential Diagnosis of Hidden Hearing Loss, documented hearing loss in young musicians that was not detected by standard pure-tone audiometry but was detected by more sophisticated tests. In his paper, Dr. Maison wrote that his study “aimed to test the hypothesis that ‘hidden hearing loss’ is widespread among young adults with normal audiometric thresholds, especially those who abuse their ears regularly.” To test this theory, they “recruited young adult subjects and divided them according to noise-exposure history into high-risk and low-risk groups.” What he and his team found were “significant deficits in difficult word-recognition tasks in the high-risk group that were associated with significant elevation of pure-tone thresholds at frequencies higher than those normally tested and with changes in auditory evoked potentials consistent with the presence of cochlear synaptopathy, also known as hidden hearing loss.”

In the second paper in The Hearing Journal, he recommends that additional tests should be added to the current audiometry protocol to detect hidden hearing loss. Dr. Maison argues that early detection must be done since “[n]oise damage early in life likely accelerates the age-related further loss of hair cells and cochlear neurons, even in the absence of further ear abuse,” and suggests that additional tests be administered to identify hidden hearing loss, noting that “recent animal research has reported regeneration of cochlear nerve synaptic connections with inner hair cells after noise exposure.” He concludes that “[c]larification of the true risks of noise, and the true prevalence of noise-induced damage, are important to public policy on noise abatement, to raising general consciousness about the dangers of ear abuse and to preventing a dramatic rise in hearing impairment in the future.”

Click the links above to read Dr. Maison’s papers. They are well worth your time.

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.

 

Better Hearing Month 2017 and the problem of noise

By David Sykes, Vice Chair, The Quiet Coalition

Every year since 1927, May has been designated “Better Hearing Month.” What better time to think about what threatens your hearing health? In fact, if you already have some hearing loss you’re one of about 48 million Americans—that’s many more than all of the people with cancer or diabetes combined.

That’s a big number, and yet hearing loss—specifically noise-induced hearing loss (NIHL)–has been overlooked and underfunded for three and a half decades.

Noise is such a simple word–why is it so complex and laden with jargon and specialists who don’t talk to one another? One group is solely concerned with how to measure it (physicists). Other groups focus on specific types and sources of noise, such as jet aircraft, or alarmed medical devices, or leaf blowers, or trains, or highway noise (engineers or advocacy groups). Others concentrate on the effects of noise on humans (doctors and public health researchers), while another group ponders how noise affects organisms other than humans, including plants, birds and other animal species, including those that live underwater (biologists). Still other groups think about how to mitigate noise (architects and designers).

The problem is that over the past three and a half decades, the subject of noise and it’s effects have been systematically ignored and underfunded by Congress and the White House. As a result, “noise”–the cause of NIHL–has become a bewilderingly fragmented field in which few people talk to others outside their own specialities. This has resulted in a subject that is hard to understand and laden with technical jargon. What is “noise”? Why does it matter? Who cares? Has the science progressed? If so, how and where?

But recently that has begun to change thanks to advances in research and to changes in federal policies from several federal agencies that have not traditionally been involved in noise and noise control. These include the Centers for Disease Control and Prevention, NASA, the Department of Health and Humans Services, the Department of Interior, the General Services Administration, the Joint Commission, and others.

In each case, a specific federal department has bitten off a chunk of the noise problem and developed guidelines and programs to fit their own needs. But put all of these disparate pieces together and you will find examples of real progress despite the fragmentation.

To help build general understanding, we ar the The Quiet Coalition have assembled some of these fragments into a diagram or a “Road Map” of noise effects (see chart above) organized by the way they are studied within various specialized fields. We hope this Road Map helps others see the big picture.

In addition to the Road Map, we have also assembled the basic facts about noise into a simple one-page “Fact Sheet” that provides detailed references to scientific literature. Both the Fact Sheet and the Road Map are starting points. At The Quiet Coalition, our goal is to synthesize the underlying scientific research on this complex and fragmented subject into a coherent picture so that we can collectively find ways to talk about it. We hope you find both the Fact Sheet and the Road Map useful as you think about hearing, hearing loss, and that elusive problem, noise.

The underlying question for each of us should be: how can we work together?

David Sykes chairs/co-chairs four national professional groups in acoustical science: The Acoustics Research Council, ANSI S12 WG44, The Rothschild Foundation Task Force on Acoustics, and the FGI Acoustics Working Group. He is also a board member of the American Tinnitus Association, co-founder of the Laboratory for Advanced Research in Acoustics (LARA) at Rensselaer Polytechnic Institute, lead author of “Sound & Vibration 2.0 (2012, Springer-Verlag), and a contributor to “Technology for a Quieter America” (2011, National Academy of Engineering). A graduate of the University of California/Berkeley with graduate degrees from Cornell University, he is a frequent organizer of and speaker at professional conferences in the U.S., Europe, Asia, and the Middle East.

Is this the most thoughtful birthday present ever?

Photo credit: Dave Crosby licensed under CC BY-SA 2.0

By Daniel Fink, MD, Chair, The Quiet Coalition

In California, on his or her birthday a 16-year-old gets a driver’s license and, if he or she is lucky, a car.

One Dutch town is thinking about what may be an even better birthday present, the gift of good hearing: Dutch town considers giving birthday earplugs to all 16-year-olds.

Link via @QuietEdinburgh.