Proteins Could Restore Damaged Sound-Detecting Cells in Ears
Celebrating 35 years of Caring for Your Hearing
|Meredy Hase tests a child, 1987||Kupperman and Hase work to license audiologists in Wisconsin, 1989|
Hearing Loss UNDER Age 65
We used to think of hearing loss as something that only happened to our grandparents' generation. But you'd be surprised at how many people your age, and even younger, have a hearing problem.
According to a study recently published by the Better Hearing Institute, two-thirds of Americans with hearing loss are under the age of 65 and still in the work force. That includes one of every six "Baby Boomers" (ages 41 to 59) and one of every 14 "Generation X'ers" (age 29-40).
According to Meredy Hase, Doctor of Audiology, "Hearing loss is by no means an 'old person's disease' any longer. Each day, we see people of all ages come into our offices concerned they may have a hearing problem.
"There's even solid evidence to support the fact that for working Americans, hearing loss impacts their ability to make a living, up to $12,000 in lost income per year." (See related article)
Dr. Hase urges anyone who thinks they, or a loved one, may have a hearing loss to contact The Doctors of Audiology at Hearing Services without delay.
Auditory Deprivation refers to the fact that even though we "hear" with our ears, it's our brain that's the true organ of hearing.
When hearing loss is left untreated, the brain's ability to distinguish various sounds becomes less and less. Try to think of Auditory Deprivation as similar, in a sense, to muscles that atrophy when not used over a long period of time.
The reason Auditory Deprivation is important is that we have ample evidence proving how long people will wait before seeking help for a suspected hearing loss. Up to ten years, by some estimates.
In other words, the longer you wait to get help for your hearing loss, the less even the most advanced hearing instruments will be able to help you hear better. That's one more reason physicians recommend annual hearing checks as part of an overall health assessment.
The Doctors of Audiology at Hearing Services can perform hearing screenings that take only a few minutes. Concerned individuals are urged to contact them at the first signs of hearing loss, such as an inability to understand conversations in a crowded room or having to turn up the TV volume in order to hear.
Hearing & Income Loss
After years of research, there is new evidence that links hearing loss and loss of income. A study released by the Better Hearing Institute in Alexandria, VA, proves that untreated hearing loss may impact household income by as much as $12,000 per year.
The study also shows that hearing loss, which affects more than 28 million Americans, two thirds of whom are still in the work force, results in an annual loss of more than $100 billion in wages and worker productivity. The good news is people who find help for their hearing loss can regain up to 50% of that lost income.
According to Meredy Hase, Doctor of Audiology, "One of the misconceptions about hearing loss is that it's 'an old person's ailment'. But we know that hearing loss crosses all income lines and impacts people of all ages".
The new "Open Ear" Digital hearing instruments are especially designed to help Baby Boomers feel more comfortable about wearing hearing instruments.
Anyone interested in receiving a FREE Demonstration of Open Fit hearing technology are urged to contact the Doctors of Audiology at Hearing Services.
Hearing Loss & the Family
For years, both researchers and hearing healthcare professionals have known much about the causes of hearing loss and how it affects the person who suffers from it.
But not until recently has attention been paid as to the devastating effects hearing loss has on family members and friends as well. This past year alone, several organizations have weighed in with their findings on this often overlooked medical problem that by current estimates, affects the lives and families of more than 30 million Americans.
For example, the National Council on Aging (NCOA), a government agency whose task it is to research the lives of older Americans, released a study that confirms how often a person with hearing loss begins to feel isolated, eventually withdrawing from normal everyday activities and even from family and friends.
None of this is news, however, to Dr. Meredy Hase, who says, "I realized just how much hearing loss also affected family members when we''d spend so much time counseling them when we''d fit their loved one with hearing instruments".
The benefits of better hearing were the subject of an NBC report that aired on an installment of the NBC Nightly News. In that report, the testimonials of several patients and their families provided evidence of how lives can be changed for the good, once the decision has been made to seek help for a hearing problem.
Those interviewed talked about how experiences such as watching TV or enjoying conversations with loved ones - things that were not possible with hearing loss - were once again part of the everyday enjoyment of life. Social activities like dining at restaurants of going to the movies were also among the range of family life experienced through better hearing.
Thanks to recent advances in technology more help is available than ever before for those whose lives are affected by hearing loss. If left untreated, hearing loss will almost always become worse over time, another reason Dr. Hase urges people to contact the Doctors of Audiology at Hearing Services if a hearing loss is thought to exist.
More Hearing Healthcare News
Using genetic tools in mice, researchers at Johns Hopkins Medicine say they have identified a pair of proteins that precisely control when sound-detecting cells, known as hair cells, are born in the mammalian inner ear. The proteins, described in a report published June 12 in eLife, may hold a key to future therapies to restore hearing in people with irreversible deafness.
"Scientists in our field have long been looking for the molecular signals that trigger the formation of the hair cells that sense and transmit sound," says Angelika Doetzlhofer, Ph.D., associate professor of neuroscience at the Johns Hopkins University School of Medicine. "These hair cells are a major player in hearing loss, and knowing more about how they develop will help us figure out ways to replace hair cells that are damaged."
In order for mammals to hear, sound vibrations travel through a hollow, snail shell-looking structure called the cochlea. Lining the inside of the cochlea are two types of sound-detecting cells, inner and outer hair cells, which convey sound information to the brain.
An estimated 90% of genetic hearing loss is caused by problems with hair cells or damage to the auditory nerves that connect the hair cells to the brain. Deafness due to exposure to loud noises or certain viral infections arises from damage to hair cells. Unlike their counterparts in other mammals and birds, human hair cells cannot regenerate. So, once hair cells are damaged, hearing loss is likely permanent.
Scientists have known that the first step in hair cell birth starts at the outermost part of the spiraled cochlea. Here, precursor cells start transforming into hair cells. Then, like sports fans performing "the wave" in a stadium, precursor cells along the spiral shape of the cochlea turn into hair cells along a wave of transformation that stops when it reaches the inner part of the cochlea. Knowing where hair cells start their development, Doetzlhofer and her team went in search of molecular cues that were in the right place and at the right time along the cochlear spiral.
Of the proteins the researchers examined, the pattern of two proteins, Activin A and follistatin, stood out from the rest. Along the spiral path of the cochlea, levels of Activin A increased where precursor cells were turning into hair cells. Follistatin, however, appeared to have the opposite behavior of Activin A. Its levels were low in the outermost part of the cochlea when precursor cells were first starting to transform into hair cells and high at the innermost part of the cochlea's spiral where precursor cells hadn't yet started their conversion. Activin A seemed to move in a wave inward, while follistatin moved in a wave outward.
"In nature, we knew that Activin A and follistatin work in opposite ways to regulate cells," says Doetzlhofer. "And so, it seems, based on our findings like in the ear, the two proteins perform a balancing act on precursor cells to control the orderly formation of hair cells along the cochlear spiral."
To figure out how exactly Activin A and follistatin coordinate hair cell development, the researchers studied the effects of each of the two proteins individually. First, they increased the levels of Activin A in the cochleas of normal mice. In these animals, precursor cells transformed to hair cells too early, causing hair cells to appear prematurely all along the cochlear spiral. In mice engineered to either overproduce follistatin or not produce Activin A at all, hair cells were late to form and appeared disorganized and scattered across multiple rows inside the cochlea.
"The action of Activin A and follistatin is so precisely timed during development that any disturbance can negatively affect the organization of the cochlea," says Doetzlhofer. "It's like building a house -- if the foundation is not laid correctly, anything built upon it is affected."
Looking more closely at why overproduction of follistatin results in disorganized hair cells, the researchers found that high levels of this protein caused precursor cells to divide more frequently, which in turn made more of them convert into inner hair cells in a haphazard way.
Doetzlhofer notes that her research in hair cell development, although fundamental, has potential applications to treat deafness caused by damaged hair cells: "We are interested in how hair cells evolved because it's an interesting biological question," she says. "But we also want to use that knowledge to improve or develop new treatment strategies for hearing loss."
Article originally appeared on ScienceDaily