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Q&A: Katherine Bouton, on hearing loss and its hidden causes

Q&A: Katherine Bouton, on hearing loss and its hidden causes

Posting in Healthcare

Over 15 percent of Americans are hearing-impaired -- and one big culprit is everyday noise. We spoke with author Katherine Bouton about the causes, the damage and her own progressive deafness.

Katherine Bouton, a journalist, answered her phone one day but couldn’t hear anyone on the other end. It wasn’t until she switched from her left to her right ear that she heard a voice asking to speak with her. That was the day she discovered she had gone deaf in one ear. She was only 30.

Bouton had been to many rock concerts in her 20s but doctors found no indication that the sudden loss was due to noise or a viral infection or an autoimmune response. She downplayed the seriousness of her worsening condition for 20 years, attempting to cope on her own.

Bouton has written a memoir following the progression of her deafness, Shouting Won’t Help: Why I—And 50 Million Other Americans—Can’t Hear You.

Many might assume deafness is a challenge of aging, but it turns out that tens of millions of Americans have permanent hearing loss caused by noises we subject ourselves to everyday. Music, car alarms, hair dryers can all contribute to hearing loss. And the damage can happen much earlier than we think.

SmartPlanet asked Bouton about how she coped, some of the more surprising revelations about hearing loss and what we can do to protect our ears.

I understand that the leading cause of hearing loss is not age, as many would assume, but everyday noise that we subject ourselves to.

There are different ways noise can damage hearing. Most people know that a single blast can destroy your hearing. If you happened to be standing 100 feet from a jet engine taking off (without protective headphones), you might be deafened instantly. For soldiers in Iraq and Afghanistan, IED’s and other blast-type weapons can cause instant deafness. But more important for the large number of people is continual or frequent exposure to more moderate levels of noise.

Such as?

The noise in a subway train, for instance, is usually between 90 and 95 decibels. Running your power mower exposes you to 107 decibels. A loud rock concert can be anywhere from 115 to 125 decibels. The vuvuzuelas that characterized the World Cup in South Africa were measured at 127 decibels.

Can you give us examples that might put those levels in perspective?

Consider that OSHA permits unprotected exposure only four hours a day to noise at 95 decibels, two hours a day to 100 dB and 15 minutes or less to exposure to 115 dB.

Some scientists now think that long-term exposure even to more moderate levels of noise -- city traffic, frequent rock concerts, wearing headphones for most of the day –- may cause invisible damage that could result in earlier onset of age-related hearing loss and possibility more severe age-related hearing loss.

I understand that high-frequency sounds are the first victims of hearing loss and then comes the inability to hear the frequencies associated with speech.

Audiologists refer to the speech banana. This is the pattern on an audiogram that shows where speech sounds fall. If your hearing does not fall within the speech banana you’ll have trouble understanding speech, though you may hear it. Very few vowels or consonants fall in the low frequencies but in the high frequencies, 4000 to 8000 hz, you find the consonants f, s, and th. So people with hearing loss in that area can’t distinguish between “fish” “fist” “fifth” or “fit." I have frequency loss in the lower range as well, so I have a hard time distinguishing “mmm” from “eeee”.

Can you share one of your more intense frustrations with your own hearing loss?

My most intense frustrations were when I was still trying to hide the fact that I had hearing loss. I would literally be twisting myself into knots to best position myself to hear what someone was saying, and then I’d miss it anyway. I might ask them to repeat it once, but if I still didn’t get it, I’d let it go. I’m sure I asked many inappropriate questions, or said things that others had just said, or answered questions that hadn’t been asked. I never knew if I was hearing correctly. I avoided any kind of debate or discussion about things of importance because I simply couldn’t follow them. I was so stressed by not being able to hear and by fear of making a fool of myself that I had a permanent band of tension across my back and a constant stomach ache. I lost 20 pounds my last few years at the Times, from stress I think.

Initially you ignored your doctor's advice to use a hearing aid. Why?

I was just 30, for starters. Hearing aids were bulky ugly things back then (today they are sleek and virtually invisible). I didn’t want to look old. But I also had good hearing in my right ear, and I didn’t think I needed two ears to get along. I did manage well with one good ear for quite a long time.

Many complain that hearing aids are not all that helpful.

Hearing aids should be very helpful for those with mild to moderate hearing loss. But they have to be fitted carefully, they have to be calibrated by an audiologist, with regular follow up visits. The user has to wear them all the time, in order get the most from them. You have to learn to hear with hearing aids. Very often, the first hearing aid you try will not work especially well for you. Most companies have a 30-day tryout period, and if the hearing aid doesn’t seem right or isn’t comfortable, you should send it back and try a different one.

For people with severe hearing loss, a hearing aid just isn’t sophisticated enough to pick up all the nuances of sound. Hearing aids –- and cochlear implants –- are designed to maximize hearing speech. They’ve done a good job with that. Now the challenge is to make them even more sophisticated, so that they make music enjoyable, or allow you to hear in a noisy restaurant as well as your hearing friends do.

And they are extremely expensive?

Only one in seven people in this country who could benefit from hearing aids uses them. This is partly because of cost. The cost of a decent hearing aid ranges from $2,000 to $6,000. If you have progressive hearing loss they need to be replaced every few years. Even if you don’t, you’ll want to replace them anyway as technology improves. There is almost no insurance reimbursement for hearing aids.

Private insurance, Medicaid and Medicare cover little to none of the cost of hearing aids. This is a huge public health issue because untreated hearing loss causes a raft of public health problems: unemployment, mental issues like depression, early onset dementia. It’s really almost breathtakingly shortsighted that we fail to cover this basic coverage.

It is the hair cells in the ear that are permanently damaged, correct? What else is it about the ear that makes it particularly fragile?

There are different kinds of hearing loss, caused by many different issues, but the kind you are referring to is called sensorineural hearing loss. The hair cells, the tiny cilia in the cochlea that transmit the sound waves to the auditory nerve and from there to the brain, are susceptible to all sorts of toxins. The principal toxin is noise, but some diseases (especially autoimmune diseases), drugs like Vicodin and the cancer drug Cisplatin, and a variety of other factors can all damage the hair cells. In mammals there are four rows of cells. The three outer rows are support cells. The inner row responds to particular frequencies and releases a neurotransmitter to the auditory nerve fibers.

The outer cells often go first, and this causes a kind of muddled signal as they respond to more frequencies than they should. When this happens you can hear the sound of speech, but you can’t understand it. Many people with early hearing loss experience this. When the inner row goes, you not only can’t understand speech but you can’t hear it.

The inner ear in general isn’t particularly fragile. The cochlea is a hard bony structure, difficult to penetrate. But when loud sound or other toxins (like Vicodin or Cisplatin) affect the mechanical response of those outer cells, you begin to experience hearing loss.

Is it true that early damage to your hair cells -- can show up later in life as hearing loss? Why the delay?

Sharon Kujawa and Charles Liberman of Harvard believe that early damage can seem to be temporary. The hearing is quickly restored. But they believe that the synapses between the hair cells and the nerves may be permanently damaged, and that this can lead to perceptual problems like difficulty hearing speech in noise (very familiar to many of us), tinnitus or hyperacusis –- a painful condition in which noise often seems intolerable.

What should we do to protect ourselves?

Wear ear plugs! If it sounds noisy, it is. You can get really good earplugs for $10 or $12. Pop them in your ear on the subway or on the street where someone is jackhammering or even in a restaurant. You’ll probably still be able to hear what you need to hear. The military is developing very sophisticated ear plugs that allow the wearer to hear normal sound but that shut down sound when it reaches a certain decibel level.

I understand that portable music players can subject the ear to sound levels as high as a jet taking off, it seems incredible.

I don’t know about the jet analogy. I do know that iPods and MP3 players generally have noise caps. In the old days of Walkmen, these sound caps didn’t exist. More damage may have been done then. The problem now isn’t that the noise from iPods is so loud (though if someone else can hear what you’re hearing, it is too loud) but that they are often worn for many hours a day. So it’s a sustained exposure over a long period of time, rather than an intense short exposure.

Is it true that some children's toys are set to very high sound levels, enough to cause damage?

The Sight and Hearing Association at the University of Minnesota does an annual rating of children’s toys. In 2010, it found that two toys intended for toddlers measured 129.2 dB and 119.5 dB. Other toys were also very noisy but these two won that year’s noisiest toys award. As a general rule, if it sounds too loud to you, the parent, it’s too loud.

There is a lot of research being done on hearing loss -- can you describe one of the more promising areas, that might lead to real change soon?

There is a great deal of interesting research being done on finding a biological cure for hearing loss, either through gene therapy or stem cell therapy. I don’t think anyone thinks these techniques will be applicable to humans soon. It was only as recently as 1985 that researchers like Ed Rubel, now at the University of Washington, found that any animal could regenerate hair cells. Their first discovery was in chicks. Other researchers found that fish regenerate hair cells. Rubel and his colleagues around the country are now trying to understand how chicks and fish do it, and how that could be applied to mammals. In 2010, Stefan Heller at Stanford managed to regenerate hair cells using stem cell transplants, the first time this had been achieved in mammals. His study subjects were mice.

The research is very promising, and also a very long way from being a reality.

[Photo credit: Joyce Ravid]

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Christie Nicholson

Contributing Writer

Christie Nicholson produces and hosts Scientific American's podcasts 60-Second Mind and 60-Second Science and is an on-air contributor for Slate, Babelgum, Scientific American, Discovery Channel and Science Channel. She has spoken at MIT/Stanford VLAB, SXSW Interactive, the National Science Foundation, the National Research Council, the Space Studies Board and Brookhaven National Laboratory. She holds degrees from the Columbia University Graduate School of Journalism and Dalhousie University in Canada. She is based in New York. Follow her on Twitter. Disclosure