A Fork in the Road:  Progressive Hearing Loss

By Sara Kennedy

After three years into this journey of raising a child with a hearing loss, it was time once again for our daughter's routine annual hearing test.  My daughter hated these tests passionately, but I had grown used to them - always the same, an almost flat line at about 80-85 decibels.  This time, that line dipped to 90 - 100 decibels.  We heard for the first time the term... "progressive hearing loss."  This was followed with several repeat tests to be certain, but eventually, there it was, she was ... "more deaf". What would the description be?  For a child whom we called "pretty darn deaf", what difference would a few less decibels make?  We found that it made plenty of difference for a  child who used her residual hearing to the max.  We noticed she began to drop the /s/ plurals in words, she couldn't always hear us call her name, and the top of the line hearing aids could no longer get her up in the coveted "speech banana zone".

The resulting grief from the further loss, however small, in our daughter's hearing astounded me.  Suddenly we felt we should reexamine our choices of communication modes, choice of school environment, and even our irrational dreams for our daughter.  I thought we had "been there-done that" in terms of grief.  We were also confronted with decisions again that we thought we had successfully shelved - the decision to utilize a cochlear implant or not was one of these.

I can't imagine what our daughter went through.  Young adults who have gone through this up and down in hearing can tell us something about their experiences.  Jon Fidrych, a high school student in Fort Collins , indicates that he has to be highly literal when explaining fluctuations to adults who can't seem to grasp that he cannot hear and his hearing aid is useless.  He will tell them..."It's not my hearing aid that isn't working, it's my EAR!"  Even then they look perplexed.  He describes leaving for school one day when his hearing was typical for him and by the second hour of the school day, he was completely deaf.  For our daughter, she repeatedly said that one hearing aid hurt her, and sure enough her hearing had fluctuated up a bit when we took her in for testing.

What is progressive hearing loss and who gets it?  Motivated by my "knowledge is power" approach to all challenges, I looked for information.  In my search through reams of journals and web searches I was not able to find very much.  Discussing this issue with parents and professionals, I found that almost half of us with a child who had an unknown cause of sensorineural hearing loss could expect that child to lose some additional hearing.  Kathy Budney, an audiologist and regional Audiology Consultant, notices that she sees this far more often now than when she first began working with children.  She observes that this drop in hearing seems to occur most often before the age of 5.  Progressive loss doesn't necessarily mean that hearing continues to drop, as some children lose some range but then achieve a new stable level.  Others continue to fluctuate in their hearing, including fluctuating up, as our daughter did, but not all the way back to the level she had before.

Who is at risk for progressive hearing loss?  More than 400 syndromes are known to be related to hearing loss with many of these causing progressive losses.  Most well known perhaps is otosclerosis.  In this genetic syndrome, a child would show signs of hearing loss at the time of puberty and/or during pregnancy or childbirth in women. Hearing loss usually begins between the ages of 11 and 35. Otosclerosis affects one ear about 10 to 15% of the time.

For children with unilateral loss (hearing loss in one ear), it has been shown that some of those children can be expected to eventually have a bilateral loss.  (Infants with unilateral hearing loss are at risk for progressive and/or bilateral hearing loss, Brookhouser, Worthington, & Kelly, 1994.)

What might be the cause of progressive hearing loss in a child without a coexisting condition or known cause of her hearing loss?  No one knows. With the advent of more powerful hearing aids, theories of these types of aids causing more hearing loss seem compelling.  At least one study found no correlation between progressive loss and hearing aid amplification. 1  However, the researchers state that the increase in the number of progressive cases in the last two years indicates the necessity of further investigations in this field. 2   Exposure to noise is a rampant problem in our modern society with ever increasing numbers of adults and teenagers showing evidence of permanent and likely progressive hearing loss related to an environment of machinery, music, and ever present background noise.

Another theory points to newborn hearing screening, and the possibility that perhaps we are catching more children earlier, who then progress in their hearing loss. Prior to newborn screening these kids may not have been identified until their loss was more stable.  In this manner, newborn hearing screening is identifying children in time to catch a progressive loss that wouldn't have otherwise been discovered. 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 postnatally. 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.

Lastly, perhaps there are external factors that cause progressive hearing loss.  These factors include ototoxic "damaging to the ear" medications. When our already hard of hearing children are exposed to any of the over 800 known drugs or chemicals that can damage our ears, the drugs can cause more damage each time in a cumulative effect.3  Drugs known to be ototoxic are 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). Because the onset of increased hearing loss (or vertigo, tinnitus, or other ear related complaints associated with ototoxicity) would be difficult to pinpoint in children, there is little research regarding this in the literature.  

Why am I writing this article?  I want parents to realize that fluctuations and progressions in hearing loss are possible and unpredictable.  In our case, we pursued a trial of digital aids prior to considering an implant with very happy results.  Our five year old has returned to consistently turning to her name, producing those telltale /s/ sounds, and 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 know now to talk 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 also want her to have as many options as possible open to her as she grows up and begins to choose for herself how she will communicate in any given situation. . 

Action list for parents regarding progressive hearing loss:

  • Six month hearing tests may be recommended instead of the typical annual exam
  • Compare audiograms over an extended period of time, not just the two most recent audiograms.
  • When considering hearing aids, consider the most flexible gain.
  • Know your child's audiogram and functional listening level in real life.
  • Discuss the possibility of changes in hearing with an older child.
  • Always be open about communication modes - let your child's personality and situation lead.

1 Laryngorhinootologie. 1997 Mar;76(3):123-6. Streppel M; Betten T; von Wedel H; Eckel HE; Damm M; Klinik und Poliklinik fur Hals-Nasen-Ohrenheilkunde,; Kopf-Halschirurgie, Universitat Koln.

2 Ibid

3 Bauman, Neil Ph. D. See article in its entirety at http://www.hearinglosshelp.com

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