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Living Well with Hearing Loss
Kathryn Wexler, AuD
Clinical Associate Professor
Arizona State University Audiology Clinic.
The second spring 2017 ASURA seminar was very well attended with only a few empty seats and the audience was presented with a very informative, engaging talk. Professor Wexler stopped her presentation several times for questions of which there were many. A link to the PowerPoint slides can be found at the bottom of this story. The following story gives a brief over of some of the more important/interesting aspects of the presentation along with some additional links to additional germane information.
In a February 2017 CDC article it was reported “Hearing loss is the third most common chronic physical condition in the United States and is twice as prevalent as diabetes or cancer”. It is estimated that two thirds of those over seventy suffer from mild to severe hearing loss while only about twenty percent of this group uses hearing aids.
There are four types of hearing loss:
Professor Wexler then spent some time discussing the inner ear, particularly the cochlea, which is the location for the most common hearing losses. The cochlea is a spiraled, hollow, conical chamber of bone. The cochlea is filled with a watery liquid which moves in response to the vibrations coming from the middle ear via the oval window. As the fluid moves, the cochlear partition moves; thousands of hair cells sense the motion, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells. These primary auditory neurons transform the signals into electrochemical impulses which travel along the auditory nerve to structures in the brainstem for further processing (Wikipedia)
The more common causes for hearing loss associated with the inner ear are: age, noise, heredity, health factors, and head trauma. Some drugs can be very hard on the inner ear. The inner ear requires oxygen and thus good health helps maintain a good supply of blood and oxygen. Diabetes impacts oxygen supply and can impact hearing.
The next portion of the presentation reviewed what goes on during a standard hearing test and how the results are displayed via an audiogram. Typically the person being tested is placed in a sound proof booth with headphones. The examiner, starting at a low frequency, i.e., low pitch, slowly increases the loudness until the person pushes a button or raises a hand indicating they have heard the sound. This loudness is the threshold level for the pitch. This process is repeated for a range of pitches from about twenty to around five thousand hertz. Each ear is tested. The results are presented on an audiogram which is a plot of sound intensity (decibels) versus sound frequency (hertz) and shows the threshold level over the range of frequencies tested.
If a person signals they first hear the sound at forty decibels or less this is considered to be normal hearing – hearing at less than twenty decibels is considered acute hearing. Mild to moderate hearing loss occurs when the threshold level occurs between forty and eighty decibels. Eighty decibels is similar to someone shouting and if the threshold level is above eighty decibels this is diagnosed as a profound hearing loss.
Vowels and consonants occupy different ranges of the frequency spectrum. Vowels are in the low frequency spectrum between twenty to one thousand hertz while consonants live in the one to five thousand hertz range. This difference can lead to significant problems in comprehension. If the hearing loss is primarily in the high frequencies then a person would hear the vowels clearly but consonants would become blurred or undifferentiable, e.g., was it “b” or “c”. The brain makes a guess which may or may not be correct.
It turns out to be easier to decode what was said if you hear only the consonants and not the vowels. Professor Wexler demonstrated this fact nicely using the sentence “The cat sat on the mat”. She showed the audience the sentence with the consonants removed and then with the vowels removed. If you see only the vowels the sentence was almost impossible to decode while the opposite was true when you only saw the consonants.
The talk then moved on to discuss hearing aids. The Better Hearing Institute was recommended as a source for information about hearing loss and hearing aids. Some characteristics of current hearing aids:
There are many styles and options. AARP has material on the hearing aids pros and cons for seven of the most common devices.
There are three health care providers that supply hearing aids:
When you purchase a hearing aid you should focus on the features you need and not the brands. Some of the variable features available are:
The AARP has prepared a consumer guide to hearing aids.
The presentation moved on to discuss some communication strategies. It is important to remember that while you hear with our ears you listen with your brain. For those with moderate hearing loss.
The presentation ended with a very brief overview of cochlea implants which might be helpful for someone with profound hearing loss. A standard cochlear implant consists of an external portion that looks like a behind-the-ear hearing aid. It is connected by a magnetic disk to a second component surgically implanted under the skin and behind the ear. The implant receives sound from the external components and translates it into electrical energy that stimulates both high- and low-frequency hearing nerve cells (taken from AARP site). There are some standards for who is eligible and if the standards are met insurance covers the $100,000 cost of these devices. Cochlea implants are being used on older patients, some even in their nineties.
As indicated earlier there were a number of questions asked during the talk. A few of the questions and answers follow.
Story by Barry McNeill
Picture by Barry McNeill
ASU Retirees Association
Mailing address: PO Box 873308, Tempe, AZ 85287
Physical address: Community Services Building Room 201, 200 E. Curry, Tempe, AZ