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A Fork in the Road: Progressive Hearing Loss
By: Sara Kennedy, Colorado Springs, Colorado
After three years into our journey of raising a child with hearing loss, it was time once again for our daughter’s routine annual hearing test.
My daughter hated those tests passionately, but I had grown used to them – they were always the same, an almost flat line at about 80-85 decibels. This time, it was different. The line dipped from 90 to 100 decibels. We heard the term… "progressive hearing loss" for the first time. The test was followed by several repeated tests, just to be certain. But there it was; she was "more deaf."
What would the description be? For a child who was "pretty darn deaf," what difference would a few less decibels make? We found it made an enormous difference for a child who previously used her residual hearing to the max.
We noticed she began to drop the /s/ sounds in words, and she couldn’t always hear us when we called her name. Even the most powerful hearing aids could no longer provide her with enough hearing to perceive normal speech sounds.
The resulting grief from the additional hearing loss astounded me. I knew that in terms of decibels, it was a small change. However, to my daughter and to me, it was an additional and significant change. I thought we had already "been there-done that" in terms of grief, but there was more to come.
Suddenly, we felt we needed to re-examine our choice of communication modes, choice of school environment, and even our dreams for our daughter’s future, the dreams every parent secretly nurtures. We were confronted with and revisited decisions we thought we had successfully shelved – the decision to utilize a cochlear implant was one of these. I can’t imagine what our daughter went through.
Young adults who have gone through ups and downs, with respect to their hearing, can teach us something about their experiences.
Jon F., a high school student in Colorado, noted that he had to be very specific when explaining hearing fluctuations to adults who can't understand that he cannot hear sometimes. He has told them...''It's not my hearing aid that isn't working, it's my ear!''
Of course, they usually don’t get it. Although most people hear without having to think about, or work at it, it’s surprising to learn how little some people really know about their ears and hearing.
Jon described leaving for school one day. His hearing was typical for him that morning, but by the second hour of the school day, he was completely deaf.
For our daughter, she repeatedly said one hearing aid hurt her, and sure enough, her hearing had fluctuated. Although children cannot always know or find the correct words to describe the hearing changes they experience, if we’re attentive, I believe we can help them figure out, address and manage issues as they occur.
Progressive Hearing Loss
What is "progressive hearing loss" and who gets it? Motivated by my "knowledge is power" approach to all challenges, I looked for information. I reviewed reams of journals and endless Internet searches. I was not able to find very much that was really useful.
Through my discussions with parents and professionals, I learned almost half of us have children who had no known cause for their sensorineural hearing loss, and of those, most can expect their child to lose additional hearing.
K.B., an audiologist, noticed that in her practice, she sees "progressive hearing loss" far more often now than when she first began working with children. She observed that, in her experience, changes in hearing seemed to occur most often, prior to age 5.
Progressive hearing loss doesn’t mean that hearing continues to drop at a steady and predictable rate. In fact, some children lose some hearing, but then achieve a new stable hearing level. Others continue to fluctuate, losing hearing and then regaining some too, as our daughter did. Unfortunately, she never returned to her previously stable better hearing thresholds between 80 and 85 dB.
Who is at risk for progressive hearing loss?
More than 400 syndromes are known to be related to hearing loss, and many of them are associated with various types and degrees of progressive hearing loss.
Perhaps the best known of these is otosclerosis. With otosclerosis, some children show signs of hearing loss by the age of puberty. More typically, women with otosclerosis show changes in their hearing acuity through their years of pregnancy and bearing children.
For children with unilateral loss (hearing loss in one ear), an astonishing 65% of them can be expected to eventually have bilateral hearing loss. Infants with unilateral hearing loss are at risk for progressive and/or bilateral hearing loss. (Brookhouser, Worthington, & Kelly, 1994.)
What is the cause of progressive hearing loss in a child without coexisting conditions, known syndromes, etiologies or risk factors? No one knows. Of course, there are some theories to consider:
1- With the advent of more powerful hearing aids over the last few years, theories suggesting that powerful hearing aids cause additional hearing loss seem compelling. But there is scant evidence to support this theory. At least one study found no correlation between progressive loss and hearing aid amplification (Laryngorhinootologie, 1997, Mar 76 (3): 123-6. Streppel, M; Betten T; von Wedel H; Eckel HE; Damm M; Klinik unde Poliklinik fur Hals-Nasen-Ohrenheilkinde; Kopf-Halschirnurglie, Universitate Koln.) However, the researchers stated that the increase in the number of progressive cases in the last two years indicated the need for further investigations in this field (Ibid).
2- Exposure to noise is a significant problem in our modern society with ever increasing numbers of adults and teenagers showing evidence of permanent and likely progressive hearing loss related to environmental noises. For example; industrial machinery, home-owner machinery (lawn mowers, leaf blowers, chain saws etc), music delivery systems, concerts, beepers, pagers, cell phones, hair dryers, vacuum cleaners, alarms, sirens and ever present background noise. We are rarely in quiet!
3- Another theory suggests that recently mandated newborn hearing screenings has allowed more children to be identified and tracked over time. In other words, due to mandatory screenings, it can be argued that we are identifying more hearing impaired children earlier. Additionally, because early tests are acquired and hearing loss is documented, we can now witness documented changes (such as progressive hearing loss) over time within these children, which we were simply unaware of previously! As more data is collected through newborn screening, we may be able to discern much more, as indicated in Future Directions from the Joint Committee on Infant Hearing:
Because of newborn hearing screening, it will be possible to determine what proportion of early onset hearing losses are truly congenital versus those that occur post-natally. It will be possible to determine which types of hearing losses are stable as opposed to fluctuating and/or progressive. Intervention strategies could be tailored to the expected clinical course for each infant. Intervention will also be aimed at preventing the onset or delaying the progression of sensorineural hearing losses. Thus, objective techniques must be developed to assess the integrity and physiology of the inner ear.
4- Lastly, there are additional external and environmental factors that can cause or contribute to progressive hearing loss. These factors include ototoxic medications, head trauma, noise exposure, ear disease, multiple bouts of ear infections, and many others.
There are more than 800 known drugs or chemicals that can damage hearing, the drugs can cause more damage each time they are used. Drugs known to be ototoxic include; aminoglycoside antibiotics (such as streptomycin, neomycin, kanamycin); salicylates in large quantities (aspirin), loop diuretics (lasix, ethacrynic acid); and drugs used in chemotherapy regimens (cisplatin, carboplatin, nitrogen mustard).
Identifying Children with New Signs and Symptoms:
The onset of increased hearing loss (or vertigo, tinnitus, or other ear-related complaints associated with ototoxicity) is difficult to pinpoint in children. Children often don’t know the words to describe their physical changes, observations or perceptions. Imagine a child trying to describe tinnitus (ringing in the ears), vertigo (spinning sensations) or additional hearing loss. It can be a frustrating and daunting task!
Fluctuation and progression in hearing loss are possible, perhaps even probable and unpredictable.
In our case, we pursued powerful, digital hearing aids prior to considering a cochlear implant -- with very good results.
Our five year old has returned to consistently turning her head when we speak her name. She is again producing /s/ sounds, and she can even recognize her dad’s voice on the speaker phone.
If her hearing drops again, we will be more prepared to deal with the consequences, and we now know to speak with her about the possibility of her hearing being better or worse from one day to the next We will continue signing as her primary language, but we want her to have as many options as possible as she grows up and begins to choose for herself how she will communicate.
Action list for parents regarding progressive hearing loss:
1. Six month hearing tests may be recommended instead of the typical annual exam
2. Compare audiograms over an extended period of time, not just the two most recent audiograms.
3. When considering hearing aids, consider those with the most flexible gain.
4. Know your child’s audiogram and functional listening level in real life.
5. Discuss the possibility of changes in hearing with your child, as is appropriate.
6. Always be open about communication modes – let your child’s personality and situation lead.