Every year, hearing aids become more complicated, as the number of bands and automatic features increases. Despite that, these new and improved instruments are “easy to program” and “reports on them from early sales are astonishing” – or so we are told by the sales staff for the manufacturers.
In fact, when we order a set of new hearing aids, use a “first fit” to program them, and then listen to them, we invariably find that they just don’t sound clear. This presents us with a challenge.
When I use a listening scope and judge the quality of the sound, I find myself going back to an old familiar model of hearing aid and comparing its sound with that of the new one.
Old-timers like me have spent tens of thousands of hours developing competence in manipulating the sound of analog hearing instruments. We learned about dual microphones, dual receivers, high-cut, low-cut, and compression. Yet, little of this knowledge applies to today’s world of digital sound. We are like my grandmother who, when she had to give up her old wood stove, complained about cooking on “this stupid electric thing that always burns the food.”
Let’s face it, digitally processed sound has a different quality from analog sound. The distortions are different, the signal processing is different, the automatic features, like feedback suppression, are different. Digital sound is a new “ball game.” And while we recognize that digital has been on the market for more than a decade, we have not had the 10,000 hours of listening and adjusting practice needed to perfect our professional skills in fitting these constantly changing devices. So, what should we do, and where do we start in our quest to give every patient calm, clear, “wonderful” amplification?
GETTING TO KNOW A NEW AID
I give myself an hour or two to play with any newly introduced hearing aid. First of all, I turn off the compression and all the automatic features. I set the gain to about 20 dB at all frequency points and listen and fiddle with the volume. I then add 5 to 10 dB of extra gain in the zone around 2000 Hz, hoping that this will cause the sound to become brighter and clearer.
If this sounds good, I go into the noise-reduction mode, activating both microphones and following the noise-reduction protocol. In this mode, I rotate the aid front to back while talking into the instrument. If the noise-reduction mode is working, the aid sounds much louder from the front.
If I am pleased with the sound for these two basic programs, I go back to first fit and use the factory software to program the hearing aid. Again, I listen to the sound. If it sounds “weird,” I call my favorite factory support audiologist. She is worth her weight in gold and she knows much more than I do about adjusting the hearing aids. More importantly, I trust her, because I know with her there will be no games, no hype, and no product-promotion speeches.
She also knows me well, is familiar with my tendencies, and treats me like family. She gets straight to the point saying something like: “You have to do first fit. Don’t be lazy. Why on earth are you cutting the gain in that region?”
Her value to me is immeasurable. I have been in this business a long time and I’ve learned a lot. But still, without her, my life would be very difficult.
DE-BUGGING DIGITAL
Our profession learned to do harmonic distortion tests, then intermodulation tests, then real-ear tests, then… We are now learning how to find programming flaws in hearing aid fitting software. We are learning how to “de-bug” the settings that control the amplification we give the patient. When we watch digital TV we see weird things, “digital burps.” Now we’re in the process of learning how to hear “digital burps.”
SOMETIMES THE SOLUTION IS SIMPLE
One last thought. This morning I was riding my stationary bike while watching an educational video on my computer. I noticed that the sound quality was not very good. I had to laugh. I was in the middle of writing this article on sound clarity and here I was experiencing the same problem with the sound from my computer.
I stopped exercising and adjusted the sound settings on the computer. But, the sound was still muffled and distorted. I was about to get back on my bike when I noticed that one of the speakers was lying face down on the desk. Once again, I laughed.
We can spend vast amounts of energy and go through exhausting mental calisthenics only to find that our problem is ultra-simple. So, when a hearing aid doesn’t sound right, make sure the ports to the microphones and receivers are open and the sound is turned on to the proper level.
Hello Dr. Martin,
I love this article. I have been fitting hearing aids a long time too, though not as long as you. I have noticed this phenomenon of “weird” sounding digital aids when I listen to them in my quiet office, and in various other settings with other people speaking with and without background noise. My sundry manufacturers’ sales reps are as you describe, pretty pollyanna-ish (and of course bullish about their hearing aids selling like hot cakes). I’d like to know who this factory support audiologist is! Which manufacturer does she work for? She sounds like a breath of fresh air. Since you’ve already broken her in for other audiologists with similar mind-sets like yours, I won’t have to explain everything to her. I’ll just tell her, “Bob Martin said that you could help me. Why does this hearing aid sound so weird?”
I really enjoyed your honesty and humor in this article!