Corvallis Hearing Center

Audiology Clinic and Hearing Aids

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Hearing Loss and the Brain

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Frequent readers of this section are well aware that hearing loss changes the brain in ways that foster dementia. Those who have missed this news are referred to the following article (https://corvallishearing.com/hldementia)

Unfortunately, recent information suggests that well before dementia sets in there are a large series of changes that take place that make the brain function in abnormal ways (https://corvallishearing.com/congenital-deafness).

These new findings use radiographic techniques to show the numerous essential inter connections that exist between the primary and secondary auditory areas of the brain and all other parts.

These brain interconnections must be functional for people to completely comprehend spoken or written language or even maintain appropriate social behavior. To quote Dr. Kral and his colleagues, “The experienced adult brain relies on higher-order representations for generating expectations about the environment based on the context and behavioral goals. These expectations are possible since the brain has developed a meaningful representation of the world (sensory information) that is constantly updated and compared with external events. With the mature micro circuitry the auditory (area of the brain) can integrate bottom-up and top-down (sensory and intellectual) information flow. In cases of conflict between the input (from the senses) and these (memory) expectations, error signals drive plastic changes and learning. These processes require experience and a functional interareal (whole brain) and intrinsic (brain) circuitry.”

Stated differently, looking only at the auditory area of the brain is missing the point.

Knowledge of the critical importance of these inter connections brings us to an obvious question: What should we be doing to foster interconnected brain health?

Fortunately, we have research that addresses this intervention question.

First, there must be a foundation that allows for hearing the maximum number of speech sounds in individuals with hearing loss (https://corvallishearing.com/audibility).

Hearing Aid Programming Practices in Oregon: Fitting Errors and Real Ear Measurements

Depending on the level of hearing loss, this first rule mandates use of hearing aids or cochlear implants long before hearing loss becomes chronic.  Again quoting Dr. Kral and colleagues, “changes (due to hearing loss) in columnar microcircuits (deep and superficial brain connections) and interareal couplings (connections within the larger parts of the brain) limit the outcome of sensory restoration (hearing aids and/or cochlear implants) if performed late in life.

Stated differently, there is a point of no return.  The body is a habitual machine and if you let it develop bad physiological habits (untreated hearing loss) for a long period of time, these bad habits cannot be undone.

However simply obtaining timely hearing aids or cochlear implants is not enough.  These devices must be properly programmed and most are not (https://corvallishearing.com/oregon-fitting-errors)

Secondly as noted by Kral and colleagues, the individual must maintain brain stimulating, language-rich social contacts. (Use it or lose it).

To summarize, a healthy brain requires maximum audibility of speech sounds and intellectually stimulating use of those audible words.

For more in-depth discussion of this issue the reader is referred to the following summary (https://corvallishearing.com/entrain-brain).

Hearing Aids for People with Normal Hearing?

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Much research has focused on patients who self-report listening difficulties, but show normal results on the typical pure tone hearing test where you raise your hand, push a button or say “yes” when you hear the tone.

In fact, it is estimated some 26 million people in the U.S. self-report listening difficulties with normal pure tone results (see https://corvallishearing.com/hearing-difficulties for references ).

This 26 million figure would account for nearly 70% of the 37.5 million people in the U.S. who have suspected listening difficulties per the National Institutes of Health estimate.

The literature notes there are a number of auditory disorders that may not produce hearing loss as measured by pure tone testing.  These disorders include Central Auditory Processing Deficit, Auditory Neuropathy Spectrum Disorder, Cochlear Synaptosis, Hyperacusis and tinnitus to name a few.

It is not surprising then that pure tone testing popularized in the early 1940s does not address these more recently-identified auditory maladies.

In a previous article we noted several other tests are often more diagnostically revealing for the disorders listed above.  However, the question for most patients so afflicted with any of these disorders is “What can be done to treat it.”

Unfortunately, the treatment of these disorders is less clear cut than the diagnostic tests used to identify them.

In a recent article Humes (2020) made the case for use of hearing aids with many such patients who show normal pure tone test results (see https://corvallishearing.com/normal-hearing).

In the case of tinnitus (the perception of ringing, buzzing, whooshing sound or music when no sound is actually present) the hearing aid recommendation is often supported. Research has shown oftentimes the brain is essentially turning up the volume looking for sounds that are no longer as loud as they once were before the individual experienced tinnitus.  Thus, hearing aids can amplify these slightly less loud sounds back to their original volume and the perception of tinnitus in as many as 60% of patients is improved.

 

In the case of Hyperacusis (heightened sensitivity to sound, with aversive or pained reactions to normally-loud environmental sounds) this disorder is thought to result from the brain’s loudness mediating function being set at too low a volume.  As such one recommended treatment is gradual introduction of more sound oftentimes from a very low-volume hearing aid combined with counseling to calm an apprehensive patient who is already concerned about too much sound. (see https://corvallishearing.com/tinnitus for discussion).

By contrast in 260 patients with Auditory Neuropathy Spectrum Disorder, 61% of  patients reported little or no hearing aid benefit (see https://corvallishearing.com/auditory-neuropathy).

In short, successful use of hearing aids among patients self-reporting listening difficulties with normal pure tone results depends heavily on the correct diagnosis.  To quote Ghandi “A correct diagnosis is three-fourths the remedy.” It is then imperative that in-depth testing beyond the conventional pure tone examination be completed before any hearing aid recommendation is made for such patients.

Brain Resource Preservation & Hearing Aids

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This week Ron Leavitt, Au.D and Carol Flexer, Ph.D are presenting our research findings at the International Conference of the American Speech Language and Hearing Association in Orlando, Florida.

Our findings on the objective and subjective variables of patients at Corvallis Hearing Center who have scored like normal hearing people on a very difficult speech in noise test while wearing their hearing aids is our topic.
Our research is based on earlier observations showing brain function is preserved in patients who score normally while wearing their hearing aids on this same speech in noise test.
Unfortunately this earlier research showed that people with untreated hearing loss or poorer aided scores on this test showed alterations in brain function that may help explain the strong relationship between hearing loss and dementia.
At our December 12th Better Hearing Seminar at Corvallis Good Samaritan Hospital we will review new research just published by our colleagues in Australia who have also been looking at these objective and subjective variables associated with normal scores on speech in noise tests.
Both our research and that of our Australian colleagues suggest some alterations of clinical practices that may enhance the likelihood of achieving these normal scores on aided speech in noise tests and allow hearing aid wearers to function much better in noisy environments.
Join us on December 12th from 3:30 to 5 pm at Corvallis Good Samaritan Hospital in Conference Room B as we review these important findings.
There is no charge, free refreshments are served and the public is welcome.

Hearing Loss and the Brain: A Story of Evolution

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At times, medical knowledge moves forward in leaps and bounds. At other times such knowledge moves forward in a more gradual fashion. Such has been the case with our knowledge of the effects of hearing loss on the brain.

Seven years ago, Dr. Frank Lin of Johns Hopkins Medical University reported that hearing loss was highly associated with dementia and accelerated brain shrinkage.  At that time, our medical knowledge on this topic took a giant step forward.

Since that report, our understanding of this relationship has been more evolutionary.  For example, Drs. Glick and Sharma showed that untreated and poorly treated hearing loss results in a scrambling of brain resources.

These researchers showed improperly treated hearing loss results in inappropriate use of the frontal and prefrontal areas of the brain. Typically, these two areas of the brain are associated with memory and reasoning. However, in the case of poorly treated hearing loss, these two brain areas are used for understanding speech, lending credence to Dr. Lin’s hypothesis that hearing loss may overwork the memory and reasoning areas of the brain.

On a positive note, Glick and Sharma showed that properly fit hearing aids may reset the brain so that the auditory area is once again used for listening. Now the frontal and prefrontal brain areas can resume their normal functions.

More recently, it was discovered that hearing loss upsets the normal rhythmic pulses and interconnections the brain uses to communicate among its different functional areas.

Within the last few months, two separate reports out of Boston and Northwestern Universities showed reestablishing appropriate pulse rates among these different areas of the brain results in significant memory improvements in older people.

These studies, when considered together, suggest the possibility that properly treated hearing loss with hearing aids, perhaps combined with brain pulse resetting, may combat the devastating effects hearing loss may have on memory.

Currently, several large-scale studies are under way, examining the potential therapeutic benefit of properly fit hearing aids and brain pulse resetting on memory. In the interim, it appears medically prudent to treat hearing loss sooner rather than later, as the average delay between diagnosis of hearing loss and treatment has recently been reported to be nine years. It is no longer appropriate to view hearing loss as an inconvenience that can be ignored.

At our clinic, we are currently reviewing the records of 51 patients who have normal aided scores on the same speech in noise test shown by Glick and Sharma to signal brain resource preservation in hopes of identifying those therapeutic steps that can properly reset the brain.

Those interested in obtaining further information on this topic are invited to the monthly meeting of the Oregon Association for Better Hearing at Corvallis Good Samaritan Hospital, Conference Room B on the second Thursday of every month from 3:30 to 5:00 p.m.

Click Here for the Upcoming Seminar Information

What is Oregon Association for Better Hearing?

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Since 1985 the Oregon Association for Better Hearing has consumer-tested hearing aids from around the world looking for the best hearing aids at the best prices. Volunteer consumer-testers have no affiliation with any hearing aid manufacturer or hearing aid sales organization. They are not in the market to buy hearing aids, and are not encouraged in any way to do so. As such they are unbiased in their hearing aid reviews.

Product testers are fit with the newest hearing aids on the market and asked to wear these hearing aids in their own listening environments. At the end of this testing period they complete our hearing aid report card and discuss those findings at our monthly meetings. The hearing aids that receive top rankings are those that are recommended in our clinic.

In 1985, Dr. Ron Levitt founded The Oregon Association for Better Hearing, a hearing aid consumer test group. That group was established so that people who are hard of hearing could talk with unbiased, long-time hearing aid users. These hearing aid testers volunteer their time to evaluate hearing aids in an ongoing search to find the best hearing aids in the world marketplace. The hearing aids that receive top rankings are those recommended and fit on patients at Dr. Leavitt’s clinic in Corvallis, Oregon.

Since 1988 this group has educated thousands of potential hearing aid buyers. None of the product testers have any affiliation with any hearing aid sales or manufacturing organizations. None receive hearing aid manufacturer sponsorship or compensation in any form. As such, their hearing aid ratings are unbiased.

This is just what we do and who we are.

Let us know if we can help you or answer any questions you might have about hearing or The Oregon Association for Better Hearing!

541-754-1377

How to Maintain Any Hearing Aid

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This is our presentation we did on August 8th, 2019.

Regardless of hearing aid brand or model there are a number of facts that you should know to maintain the hearing aids’ optimum performance.

Watch the video below to hear us discuss 12 must know items for maintaining optimum hearing aid function.

A Source to Resources!

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Through research, networking and years of experience we have collected a huge amount of resources and put them together for your convenience. We want you to have the help you need at your fingertips. We know life is hectic and full of confusion so we hope that this is one way we can help! We have compiled resources for hearing health and information onto one useful page. Just click our link and you will have them at your fingertips. [Read more…]