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Hearing Restoration: A Step Closer?

Photo credit: Ronna Hertzano et al. licensed under CC BY 2.5

By Daniel Fink, MD, Chair, The Quiet Coalition

A recent report that scientists in Boston have caused human hair cells to regrow in the laboratory is exciting news, holding out the promise of hearing restoration in the future.

But it is important to remember two facts:

1. Development and then approval of this technology for human use are likely to be years if not decades in the future, and the technology will most likely be very expensive.

2. Noise-induced hearing loss is 100% preventable and prevention is either free or inexpensive: avoid loud noise exposure and use hearing protection (ear plugs or ear muffs) if one 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.

 

A lowly fly may offer hope to hearing loss sufferers

Photo credit: Jpaur licensed under CC BY-SA 3.0

And Michelle Pucci, TVO, tells us how in her article, “How a tiny fly on a treadmill could lead to better hearing aids.” Pucci introduces us to the research team studying the ormia ochracea, a small fly that is drawn to “crickets’ singing, but no one quite knows how it manages to pick out that sound amid the cacophony of the natural world and locate it so precisely.” Why is this important?  Because if researchers can determine how the fly “pinpoints individual sounds in a noisy setting,” writes Pucci, “it could help solve the so-called cocktail party problem — the one that makes it tough for your grandmother to hear what you’re saying at family functions (and causes her to shout at you), because her hearing aid picks up too much background noise.”

Andrew Mason, a biologist at the University of Toronto explains that the fly’s “eardrums work like a scale, and incoming noises tip the balance.” Unlike humans, the fly’s “eardrums are connected — which Mason says could explain why the fly tries to interpret the different levels of sound it receives in both ears.”  Humans, on the other hand, can “locate and isolate the sounds they want to listen to, even in noisy environments, if the sources are far enough away from one another.”

The problem hearing aid wearers experience is that “it’s impossible to focus on a single conversation in a noisy room…because hearing aids trick the ear into thinking all those sounds are the same distance away.” That is, the hearing aid amplifies everything, making the task of concentrating on one conversation among many impossible. As researchers learn more about the ormia ochracea’s excellent sound-location abilities, engineers have used that knowledge.  Today, mics in some hearing aid design “mimic the fly’s ear structure,” and “research groups around the world are working on hearing aids that would allow the wearer to home in on different frequencies.”

So why do ormia ochracea search for crickets?  The answer is pretty grim:

[T]he female deposits its spawn inside the crickets, who sing when looking for a mate. Black-striped larvae then hatch inside the doomed cricket and scrape at its innards for 10 days…before “bursting out of the side like in Alien.”

Another Silent Spring

By Daniel Fink, MD, Chair, The Quiet Coalition

In 1962, Rachel Carson’s “Silent Spring” described the harmful effects of insecticides and herbicides on birds, beneficial insects, animals, and humans.  Her book helped start the environmental movement. For too many people, this will be another silent spring, caused not by a dearth of birds but because people can’t hear birds sing. They have hearing loss from another environmental pollutant, noise.

Carson described how nature’s balance controlled pest species naturally, and how these species became problems only when humans changed the environment. She noted the difference between apparent short-term safety of agrichemicals and longer-term danger. People could get sprayed with pesticides or even ingest them without apparent immediate harm, with cancer and birth defects coming later.

If Carson were alive today, she might write about noise pollution, which interferes with animal feeding, communication, mating behaviors, and navigation in forests, fields, and oceans, and causes hearing loss and other medical problems in humans.  In nature’s quiet, animals developed exquisite hearing to find food or avoid being eaten. An owl can find a mouse under a foot of snow, and zebras can hear lions approaching in the veldt.

Humans are also born with excellent hearing.  Brief exposure to loud noise usually doesn’t cause obvious auditory damage in humans, but longer or repeated exposure does. The relationship between noise and hearing loss was first noted in medieval times in bell ringers and miners, then in boilermakers during the industrial revolution.  Noise wasn’t a widespread problem, and except in large cities life was usually quiet.

Industrialization, mechanization, and urbanization made life noisier.  Noise was recognized as a public health hazard in the early days of interstate highways and jet travel, but was also considered an environmental pollutant. In 1972 Congress passed the Noise Pollution and Abatement Act, empowering the Environmental Protection Agency (EPA) to establish noise standards and require noise labeling for consumer and industrial products.

During the Reagan administration, however, Congress defunded EPA noise control activities. Little has been done since to control noise, and our country has gotten noticeably louder. Sound levels of 90-100 decibels or louder are reported in restaurants, clubs, retail stores, movie theaters, gyms, sports events, concerts, and parties, from sirens, vehicles, landscape maintenance equipment, and construction, and for those using personal music players.

The National Institutes of Health states that prolonged exposure to noise at or above 85 decibels can cause hearing loss. This is misleading, because no exposure time is given and hearing damage occurs at much lower levels. The 85-decibel standard is an occupational noise exposure standard, not a safe noise level for the public.. The EPA adjusted the occupational standard for additional noise exposure outside the workplace to calculate the noise level for preventing hearing loss to be a daily time-weighted average of only 70 decibels.

Hearing is the social sense, required for spoken communication. About 40 million American adults age 20-69 have noise induced hearing loss, half of them without noisy jobs. Why is this happening? They are exposed to loud everyday noise.  Cumulative noise exposure eventually causes hearing loss, affecting 25% of those in their 60s, half in their 70s, and 80% in their 80s, and is correlated with social isolation, depression, dementia, falls, and mortality. Due to denial, stigma, and cost only 20% of older Americans with hearing loss acquire hearing aids, after an average seven-year delay, and 40% of people with hearing aids don’t use them much, largely because hearing aids don’t help users understand speech well in noisy environments.

Preventing noise-induced hearing loss is simple: avoid loud noise. If it sounds too loud, it is too loud. Free or inexpensive smart phone sound meter apps make it easy to measure sound levels, but if one can’t converse without straining to speak or to be heard, ambient noise is above the auditory injury threshold of 75-78 decibels and auditory damage is occurring.

A quieter world is easily attainable. Whisper-quiet dishwashers, cars with quiet interiors and exhausts, the Airbus A380, and a few quiet restaurants and stores prove this.   Effective noise control technologies have long existed, including noise reduction via design and material specifications and sound insulating, isolating, reflecting, diffusing, or absorbing techniques.  Indoors, all that may be necessary is turning down the background music volume, which costs nothing.

In the 1950s and 1960s, half of all American men smoked and public spaces and workplaces were filled with tobacco smoke. When research showed that tobacco smoke caused cancer and heart disease, governments restricted smoking, leading eventually to today’s largely smoke-free society. Smokers can still smoke, but can’t expose others involuntarily to their smoke.

Noise causes hearing loss. Governments should set and enforce indoor and outdoor noise standards, to reduce each person’s daily noise dose. Adults have the right to make and listen to all the noise they want, but not where others can hear them. If we can breathe smoke-free air, we can make a quieter world, so future generations won’t have to endure another silent spring.

Dr. 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.

Originally posted at The Quiet Coalition.

Does the sound of chewing or pen clicking make you enraged?

You are not alone.  Misophonia is a disorder marked by “a hatred of sounds such as eating, chewing or repeated pen clicking.”  It’s not well understood, but the known universe just got a lot bigger thanks to a team of researchers from Newcastle University who have evidence that enraging noises are caused by a brain connection overdrive.

The lead researcher, Dr Sukhbinder Kumar of the Institute of Neuroscience at Newcastle University and the Wellcome Centre for NeuroImaging at University College London, said that, “[f]or many people with misophonia, this will come as welcome news as for the first time we have demonstrated a difference in brain structure and function in sufferers.”   With this news suffers may see the end of one problem they often face; namely, the casual dismissal of their complaints by medical professionals.  As Dr. Kumar notes, “[t]his study demonstrates the critical brain changes as further evidence to convince a sceptical medical community that this is a genuine disorder.”

 

Think you’re improving your health by going to a spinning class? Think again:

Study says loud music played during classes may contribute to hearing loss.  , Boston Magazine, reports on a Massachusetts Eye and Ear Infirmary study that found that “the speaker-shaking beats at your local studio may contribute to hearing loss over time.”  According to Duchame, researchers using a smartphone app called SoundMeter Pro found that “[t]he average noise exposure in a single 45-minute cycling class…was more than eight times higher than the National Institute for Occupational Safety and Health’s (NIOSH) recommendations for an entire eight-hour work day.”  Duchame notes with alarm “past hypotheses that exercise compounds noise-induced hearing damage,” adding that “[i]nstructors and repeat class attendees, logically, are at highest risk.”

Thanks to @QuietEdinburgh for the link.