High Frequency Hearing Loss
 By Hugh Hetherington

High frequency hearing loss is probably the most prevalent type of hearing loss in the adult population today.  It certainly would not surprise me if up to one third of the adult population suffered from some degree of this type of loss.   Because of its insidious nature in the way that it creeps up on us slowly, it can go largely unrecognized in most people for many years.  In many instances, it is not even a case of denial.  People are just unaware that they have hearing loss.  In fact, when it is recognized, it is usually a family member or friend who first recognizes it.

It has two major causes.  The first is called presbycusis, or age-related high-frequency hearing loss.  This happens naturally in many people as they age, as the very fine hair cells in the cochlea that sense the high frequencies die off and thin out.  At one time, this was considered the major cause of this type of hearing loss.  The second significant cause is from prolonged noise exposure either in the work environment or other leisure activities.  Over many years, the world has become a very noisy place and its population is subjected to high levels of noise either purposely or inadvertently.  This is starting to take its toll, especially in the youth.

Hardly a week goes by without some article appearing in the news media about the epidemic proportions of hearing loss being detected in young people through the use of walkmans and other types of music players or by regularly attending rock concerts.  With the current knowledge about how loud sounds can affect our hearing, it is about time we learned how to practice “Safe Listening”.  Even in industry, hearing conservation is not universally practiced.  I have witnessed many instances of employees potentially damaging their hearing through lack of knowledge or caring by themselves or their employers.  The sad thing is that once the hearing loss is recognized, it is permanent and there is no going back.

I personally have had this type of hearing loss for many years and have come to understand the way it affects us as individuals.  It all started over 50 years ago.  Noise related hearing loss was not yet on our radar screens.  Even though we didn’t have portable music players in those days, unfortunately, employers were not aware that subjecting  their employees to high levels of noise on a daily basis would come back to haunt those employees many years later.  I don’t remember hearing protection being anywhere in sight until the 1970’s.  Even then it wasn’t universal and it still isn’t today.

One of my earliest recollections of a hearing aid was a neighbour who wore a Zenith body aid in the early 1940’s.  He was employed in a boiler factory and at one time told me that he was able to turn off his hearing aid while at work and was not bothered by the noise.  Today, I just wonder if the nature of his work caused his hearing loss in the first place.  I don’t think this thought occurred to me at that time.

It wasn’t until after I retired from the work force that I recognized my hearing loss.  I know it was probably known about through hearing tests conducted at work in later years, but ironically this was long after I had ceased to work in a noisy environment.  Nothing was ever mentioned about it either.

I think I first became aware of my hearing loss through my wife, although not in the way that you would suspect.  When she would ask me something, often without context, I would have to ask her to repeat the question.  However, before she got the first word out in repeating, my mind had already worked out what she had asked and the repetition became unnecessary.  Humorous as it is now, this only led to accusations that the only reason I asked her to repeat was so that I had time to think up the answer to her question.

There is a very interesting thing about hearing loss.  Hearing takes place in the brain and it is capable of filling in sounds that are not heard.  For example, with high frequency hearing loss the letter “s” is one of the sounds that are not heard distinctly.  Since this letter forms the plural of most English nouns, the subject of the sentence  indicates to the brain when the “s” sounds should be present even if it is not heard distinctly and causes us to think we heard it.  This phenomenon also happens with other high-frequency sounds that are difficult to distinguish, such as, “f”, “th”, “sh”, “ch”, etc.  The brain can become very adept at making us believe we heard sounds that weren’t there simply because context dictates that they should be.  Unfortunately, this doesn’t work 100 percent and we do things wrong occasionally.  If it did work, perhaps we wouldn’t need hearing aids.

It is this characteristic of high frequency hearing loss that makes it difficult to accept that there is a loss.  It can be further compounded when a hearing professional advises you that you are not ready for a hearing aid just yet.  I spoke to one person recently who has been complaining for some time that he can’t hear in noise or in group conversations.  Although he was ready to do something about his hearing loss, and audiologist told him that his hearing wasn’t bad enough to warrant a hearing aid.  If hearing loss is causing you problems in your daily life, it is time to do something about it.  It is definitely a quality of life issue.

Another incident that helped me realize that I had a hearing loss happened while I was out walking in Capilano Canyon near the Cleveland Dam on a rainy day.  I was carrying an umbrella and while observing the water flowing over the dam from a viewpoint in the woods, I noticed that when I tilted the umbrella back behind my head, the noise of the water rushing over the dam became significantly louder.  The umbrella acted as a reflector to capture more sound.  This incident convinced me that the sound I was hearing was subdued and muffled.

Of course the classic symptom that left me with no doubt that I had a hearing loss was the significant difference in the volume setting for the television set that my wife and I needed.  Added to this were the numerous times I was told, “Turn it down”.  Getting myself a pair of earphones for the television easily solved this problem.

Although at the time I felt that my hearing loss did not have significant impact on my ability to communicate, I did realize that doing something about it would have a great impact on those who were trying to communicate with me.  What I underestimated was the tremendous improvement in the quality of my own life that took place because of my decision finally to do something about the hearing loss.  I have since become a strong advocate for using hearing aids and assistive listening devices even in the early stages of hearing loss.

Mind you, that is only part of the story.  Going out and getting a hearing aid to suit my hearing loss presented a whole series of other problems.  Even in the mid-1990’s when this was happening, the technology available was not ideally suited to treating high-frequency hearing loss.  I found that even some of the hearing professionals did not understand this type of hearing loss the way I was beginning to understand it.  I did find, however, that being a member of CHHA was very helpful since I was in contact with other people with hearing loss and was able to learn a lot from their experiences, as well as my own.

After my first hearing test, I was told that I really didn’t need a hearing aid, but if I wanted to pursue it, they could help me.  I inquired as to what type of hearing aid they would prescribe for my loss.  I was told that a deep insertion canal aid would be best.  From my own research, I knew that this was wrong since all of the sounds would have to go through the hearing aid.  Not only would I have total electronic sound, but also my ear canal would be occluded with all of the additional problems that brings on.  My low frequency hearing was fine.  I just needed a boost for the high frequencies.

After my next hearing test, a different audiologist was reluctant to provide any amplification, especially in my better ear, because she felt that my hearing would be further damaged.  I managed to talk her into ordering me a pair of open ear molds to try with a pair of Unitron BTE (behind the ear) hearing aids.  These were for mild hearing loss and with the very open molds, the low frequencies were bled off and not significantly increased.  While not the perfect solution, these did work reasonably well.  Unfortunately, the molds were far too open and didn’t stay in my ears very well.

A few years later I was given a pair of Widex Quattro Q9 hearing aids that had belonged to someone who had passed away.  The Q9’s were digitally controlled analogue hearing aids manufactured just prior to the advent of digital hearing aids in the 1990’s.  With the help of my audiologist, we had a new pair of molds made and I personally modified these into a well fitting pair of open molds.  This solution was very successful for my hearing loss, especially since the Quattros were capable of providing four separate programs for different listening situations and could be programmed using the remote control with a special key.  The Quattros were exceptionally good for high-frequency hearing loss because of the low cut and inverse presbycusis filters that could significantly reduce the low-frequency amplification.  With the open molds, the amplified low frequencies were bled off and the natural low frequencies could enter my ears through the open molds.  The high cut filter also proved advantageous for the noise program.  In addition to all of this, the Quattro Q9’s had directional microphones that further improved the listening situation.

Now you might be wondering why I am telling you all of this experience with different hearing aids.  The reason is that today there is no reason why anyone should have to struggle to get their high-frequency hearing loss treated.  Finally, technology has caught up with what I effectively had to pioneer for myself.  In just the last two to three years, two new types of hearing aids have been introduced to the market, “open fit” hearing aids and “receiver in the ear” (RITE) hearing aids.  Both of these types of hearing aids are tiny BTE aids that use micro tubing or an actual receiver in the ear canal to deliver a high-frequency boost without occluding the ear canal and with such total comfort that you can be unaware that you are even wearing a hearing aid.  All of this has been made possible by the digital technology that has largely taken over from the older analogue types of hearing aids.  These new aids are now produced by almost every hearing aid manufacturer and make it possible to treat a type of hearing loss that was problematic with the older analogue technology. Many also feature directional microphones, noise reduction, feedback suppression, telecoils and other marvelous features.  There are also models that will connect wirelessly to your cell phone or MP3 player.

The important point is that open-fit and RITE hearing aids leave the ear unoccluded, providing a more natural sound quality to the user’s own voice.  For high-frequency loss, the unoccluded ear will hear low-frequency sounds naturally through the ear canal, offering a more natural sound quality than a hearing aid that fills the ear canal.