Tag Archive: researcher

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.

 

Animals are responding to human noise:

Bats are adapting their hunting strategies to the noise of our cities.  The good news is that a study published in Science shows that bats appear to be successfully adapting to human noise.  But as a researcher not involved in that study notes, “[s]ome animals probably can’t [adapt].”  So what happens to them?  And what about humans?  As the world gets noisier, how will we cope?  Or not?  It’s certainly something that should be addressed sooner rather than later, because, as the article reports:

“This is way beyond bats now. This is about thinking about any animals,” says Paul Faure, the director of the Bat Lab at McMaster University, who was not involved in the study. “We are domesticating our planet, we’re creating noise pollution, we’re creating light pollution. We’re fundamentally altering the world that we live in.”

Noise and its effect on all animals, including humans, has been ignored for too long.  It’s more than just a nuisance.  Among other things, noise can damage hearing with one exposure.  It’s time that the federal, state, and local governments step up and regulate noise much as they regulate air or water pollution, treating noise as the public health hazard that it is.  It also is time for adults to assume some responsibility for their hearing and their children’s hearing by protecting themselves and others through the use of ear plugs and ear muff protectors, or by the simply lowering the volume when they can, and leaving a loud space when they cannot.  It’s time that we take noise-induced hearing loss and other noise-induced hearing injuries seriously.  Because until we do, people will continue to suffer permanent hearing injuries for which there is no cure, a particularly galling situation when one considers that noise-induced hearing injuries are 100% preventable.

Protect your ears! Noise causes hearing loss and more:

New study finds that nearly 10% of U.S. adults experience tinnitus.

Dr. Harrison Lin, a researcher at the University of California, Irvine, notes that “the new study as well as a number of previous studies have point to noise exposure as the probable contributor to the issue.”  Think that tinnitus is just a little ringing in your ears that will go away?  Wrong.  The study reported that “[m]ore than 33 per cent of respondents reported almost constant symptoms,” and those symptoms could interfere with “thinking, emotions, hearing, sleep and concentration.”

Click the link for the full story.