Tag Archive: hearing loss

New Zealand researchers agree: hearing loss is probably a dementia risk factor

By Daniel Fink, MD, Chair, The Quiet Coalition

Many people don’t understand the process of medical and scientific research and how different hypotheses are developed and tested, using different methods in different human populations with animal studies when possible, until a consensus is reached. This was how researchers–including doctors, epidemiologists, researchers using animal models, and scientists doing basic research at the cellular, molecular, and genetic levels–figured out that cigarette smoke causes cancer and many other diseases, and how it does this. Despite the broad scientific and public health consensus, there are still skeptics, such as those at the conservative Heartland Institute, who say there is still doubt about whether smoking causes lung cancer. There is also a Flat Earth Society. Many Americans think that evolution is an unproven theory despite more than a century of research and strong evidence supporting evolution.

For the rest of us who believe in evidence-based science and evidence-based social and economic policies, our understanding of reality is always evolving based on the evidence. Sometimes something long thought to be true is found not to be correct after all. In medicine, one of the best examples may be ulcers in the stomach and small intestine, which for decades were thought to be caused by too much stomach acid but were found to be caused by bacteria. Australians Barry Marshall and J. Robin Warren won the Nobel Prize in 2005 for making this discovery. But most of the time an early hypothesis is confirmed by one study, and then another, and then by studies in animal models, and then by basic science research, until a broad consensus is reached.

This is what is happening with the hypothesis that hearing loss is associated, probably causally, with dementia. Dr. Frank Lin at Johns Hopkins University may be the best-known researcher in this field but other researchers in other countries are studying the same question. This report from New Zealand discusses what is being done there. And this report from the UK discusses research presented there.

It’s always good to have confirmation of research by different researchers using different techniques in different populations. Such confirmation helps validate initial findings in one population and help move our understanding forward. We know that noise exposure causes hearing loss. If hearing loss is shown to be causally associated with the development of dementia, then preventing hearing loss should help to also prevent dementia. One theory is that they brain needs input to maintain function, and without auditory input and/or social connections, brain function declines. Another theory is that whatever degenerative process causes hearing loss also causes loss of mental function. Ongoing studies, providing hearing aids to those with hearing loss but not to others and then measuring intellectual function over time, may elucidate the cause-effect relationship. Regardless, we don’t need to wait for more evidence for the link. Preserving one’s hearing should be enough reason to avoid loud noise or to wear ear plugs if you can’t.

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.

Why do humans suffer hearing loss from noise?

Image is in the public domain in the U.S.

By Daniel Fink, MD, Chair, The Quiet Coalition

Why do humans suffer hearing loss from noise? The cellular, sub-cellular, and even molecular reasons for how noise damages the auditory system are known, but why?

In a fascinating article in The Hearing Journal, evolutionary biologist William Shofner, PhD, notes that humans and our animal forebears evolved in a largely quiet environment. Exquisitely acute hearing was important for finding prey or avoiding threats, but resistance to noise damage in the auditory system conferred no selective advantage.

Our world only started getting noisy as cities evolved, and especially since the Industrial Revolution. That is, our ears haven’t evolved to handle the noise, hence the epidemic of noise-induced hearing loss reported by Centers for Disease Control and Prevention.

Shofner’s last paragraph says it all:

Why didn’t evolution make the ear more noise-resistant? Again, evolution does not proceed with purpose. Simply stated, the human ear did not evolve under conditions of high sound levels. Any genetic mutation that might have led to a noise-resistant ear was likely not selected because it did not provide any benefit for survival and reproductive success in the pre-historic acoustic environment of early mammals. Natural selection is an exceedingly slow process that occurs over many generations, and the susceptibility of the human ear to noise-induced damage shows how natural selection is unable to keep up with rapid changes in an organism’s environment (Evol Applications. 2008). Technology has produced an acoustic environment that has changed much faster than the sluggish pace of human evolution. This evolutionary explanation of why the human ear is so susceptible to damage at highly intense noise levels provides a valuable perspective that audiologists can offer patients to prevent NIHL.

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.

 

Millions of people don’t protect their ears

Photo credit: Quinn Dombrowski licensed under CC BY-SA 2.0

By Daniel Fink, MD

Noise is a medical and public health problem, and yet people ignore it at their own peril. Most of us are exposed to too much noise every day. That may explain why the Centers for Disease Control and Prevention found that about 25% of adults age 20-69 had hearing loss, and that many people with hearing loss didn’t know they had it.

Which is why a recent article by Mark Fischetti in Scientific American,A Loud Warning: Millions of People Do Not Protect Their Ears,” is particularly disturbing. Fischetti reports that while “many people know that they should use earplugs or earmuffs when mowing the lawn or partying at the club,” they don’t protect their ears against noise at home or at work. If you click the link to the article, you’ll see a frightening infographic that very clearly shows that millions of Americans are at risk of losing their hearing or suffering other hearing damage because they fail to protect their ears.

Maybe if people knew that noise caused hearing loss, tinnitus, and hyperacusis–none of which can be cured–they might be motivated to protect their hearing and fight for quiet.

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.

Experts: Hearing loss is on the rise among young adults

Photo credit: Stefan Schmitz licensed under CC BY-ND 2.0

and their personal audio devices may be at least partially to blame. Melanie Campbell, a professor of Rehabilitation Medicine at the University of Alberta, warns that young adults “may be destined to swap out their headphones for hearing aids.” The problem is that this cohort “particularly loves music, they love it loud and they have very few worries about the future.” Campbell notes that World Health Organization statistics show that “[m]ore than one billion young adults are at risk of hearing loss,” and “[a]mong people aged 12-35 years, almost half are exposed to dangerously high levels of noise from personal audio devices like headphones while four out of 10 are exposed to unsafe levels of sound at concerts and other entertainment venues.”

According to Campbell, the primary cause for this hearing loss these days is noise-induced hearing loss (NIHL). What makes hearing loss particularly insidious, is that people generally don’t lose their hearing overnight. Instead, says Campbell, “[i]t creeps up and you gradually forget that you’re not hearing the door squeak, or you don’t hear people’s heels on the floor.”

To give young Canadians the information they need to protect their hearing and prevent hearing loss, Campbell has been promoting Sound Sense, a project led by the Hearing Foundation of Canada that spreads awareness about hearing loss in Canadian schools.

Spreading awareness about NIHL and how to prevent it is, of course, the the best option. Every school in the U.S. should regularly test students’ hearing and include information about NIHL in their health education programs. Given that NIHL is 100% preventable, the failure to educate children about how they can avoid NIHL is as insidious as the disorder.

 

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.

The problems with hearing aids

Photo credit: Steve Johnson licensed under CC by 2.0

and the solutions. Manfred starts her piece with a stunning statistic: “A whopping 80 percent of adults between the ages of 55 and 74 who would benefit from a hearing aid do not use them.”  Why? For a variety of reasons: discomfort, disappointment with the sound quality, difficulty in using them, expense, and a fear of “wear[ing] something associated with ‘old.’” But what these people don’t realize, Manfred writes, is “the profound damage that uncorrected hearing loss can do to your physical, emotional and cognitive health.”

Click the link to read about the effect of hearing loss on the brain–it’s profound–and read Manfred’s responses to the various excuses people give for not getting a pair of hearing aids.  As she notes, they aren’t perfect, but it’s better to deal with little imperfection than the consequences of not wearing them.

Who should get their hearing checked? Everyone!

By Daniel Fink, MD, Chair, The Quiet Coalition

This local television anchor recommends that everyone get his or her hearing checked.

But this isn’t what the experts at the U.S. Preventive Services Task Force recommend. They reviewed the published medical literature on screening for hearing loss and concluded that, based on the literature, there is no proven benefit to screening for hearing loss in adults. People who complain of not being able to hear should be checked, they cautioned, but they found no benefit in looking for hearing loss is those who don’t have an obvious problem.

Maybe it’s time to rethink that recommendation. A recent report from the Centers for Disease Control and Prevention (CDC), Vital Signs: Noise-Induced Hearing Loss Among Adults, found the following based on recent data from the National Health and Nutrition Survey:

Results: Nearly one in four adults (24%) had audiometric notches, suggesting a high prevalence of noise-induced hearing loss. The prevalence of notches was higher among males. Almost one in four U.S. adults who reported excellent or good hearing had audiometric notches (5.5% bilateral and 18.0% unilateral). Among participants who reported exposure to loud noise at work, almost one third had a notch.

Conclusions and Implications for Public Health Practice: Noise-induced hearing loss is a signficant, often unrecognized health problem among U.S. adults. Discussions between patients and personal health care providers about hearing loss symptoms, tests, and ways to protect hearing might help with early diagnosis of hearing loss and provide opportunities to prevent harmful noise exposures. Avoiding prolonged exposure to loud environments and using personal hearing protection devices can prevent noise-induced hearing loss.

Audiometric notch is the hallmark of noise induced hearing loss.

The CDC information that a quarter of American adults have hearing loss but don’t know it–including those who rate their hearing as good or excellent–indicates a major problem. Experts recommend checking blood pressure at every doctor visit and cholesterol at varying intervals, depending on risk factors, beginning in childhood. Screening for auditory disorders is recommended for children but not for adults. But hearing loss is like high blood pressure or high cholesterol–it is painless and asymptomatic, and unless someone checks, the patient doesn’t know that he or she has it.

Why does this matter? Most Americans, including most doctors and audiologists, don’t know that the only safe noise exposure level to prevent hearing loss is only 70 decibels time weighted average for 24 hours with the real safe noise exposure level probably even lower than that. Most Americans don’t know that we are exposed to dangerous levels of noise every day, which probably explains the recent CDC findings. If people know that they have hearing loss, perhaps they will do more to protect their ears.

Significant hearing loss with age is probably not part of normal physiological aging, but represents noise-induced hearing loss. (I will be presenting a paper on that topic at the 12th Congress of the International Commission on the Biological Effects of Noise.)  Regular hearing testing could prevent current and future generations from losing their hearing.  Why? Because noise-induced hearing loss is 100% preventable, and regular tests would let people know whether and to what degree their hearing is compromised, allowing–and encouraging–them to take action today to avoid significant hearing loss tomorrow.¹

Take the initiative with regard to your hearing health, and have your hearing tested regularly as part of a preventive health plan.

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.

¹ For those who are concerned about establishing the diagnosis of hearing loss as a pre-existing condition which might increase their insurance rates or exclude coverage for future hearing health care, they should not be worried for two reasons: (1) Medicare and Medicaid don’t have a pre-existing condition exclusion, and (2) federal and commercial insurance plans do not cover audiology services and hearing aids. Which is more important? Not establishing a pre-existing condition for something not covered by insurance, or finding out that your hearing is already being damaged and having the chance to take steps to protect your ears?

What Your Patients Don’t Know Can Hurt Them

Photo Credit: Flávia Costa licensed under CC BY 3.0

By Daniel Fink, MD, Chair, The Quiet Coalition

It looks like the truth about noise-induced hearing loss is finally getting out.  This article in The Hearing Journal, which claims to be “the most respected journal in hearing health care,” discusses the fact that noise causes hearing loss.  While hardly an earth shattering assertion, the article notes that “[h]earing loss has long been thought to be an unpleasant but inevitable side effect of aging.”  But, the article continues, “within the past year, two reports from the Centers for Disease Control and Prevention (CDC) have documented the startling degree to which noise—both in the workplace and elsewhere in our daily lives—contributes to hearing damage.”

What follows is a well-reasoned and complete discussion about noise-induced hearing loss. The article cites the new acting director of the CDC, Ann Schuchat, MD, and Rick Neitzel, PhD, the public health researcher and a co-founder of The Quiet Coalition. The only criticism I might offer is that the article doesn’t clearly state that the only safe noise level to prevent hearing loss is a daily average of 70 decibels time weighted average (see, “What Is a Safe Noise Level for the Public?“) and that the auditory injury threshold is only 75-78 A-weighted decibelsThose caveats aside, click the first link above to read the article.  It’s 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 and is the interim chair of Quiet Communities’s Health Advisory Council and 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.