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HearUSA - Newsweek - September 2024

Interview with Dave Fabry Director of Clinical Research, Phonak, Naperville, Illinois

Dave Fabry, PhD

May 26, 2003
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Topic: Hearing Aid Technology - New Developments

AO/Beck: Hi Dave. As always, it's great to spend a little time with you. Why don't we talk about your role as the Director of Clinical Research and some of the clinical research programs going on at Phonak?

Fabry: Sure. My role is to oversee clinical trials taking place in the U.S. and to participate in the clinical trials underway worldwide. The nature of the projects changes with product development and research, and so the process is really fascinating.

AO/Beck: Are there any specific areas you'd like to address today?

Fabry: Yes. There are three projects I'm currently involved with. Nemotech and eShells, directional microphones, and FM technology.

AO/Beck: Very good. Please continue.

Fabry: The Phonak team has been working in collaboration with Siemens Hearing Instruments, to produce hearing aid shells using digital mechanics . In brief, this process comprises three stages: scanning of earmold impressions, rapid shell computer modeling (RSM) and laser sintering (a three-dimensional copy) to produce a nylon shell that is stronger and more comfortable than UV shells. Phonak calls this process Nemotech, and Siemens calls it LaSR. We're coordinating our clinical trials and basic research with Siemens to optimize the fitting of rigid shell hearing aids in dynamic ears. To support that work, we've got a number of studies going on. So that keeps me pretty busy.

In addition, directional microphones have been an area of interest for me for a long time and Phonak is heavily invested in research and development of better directional microphone technologies too. A continuing challenge is to develop and refine hearing aids that can actually compensate for different listening environments automatically by changing their directivity patterns. Essentially, Phonak has been working to develop circuits that know whether you are at home or a party.

I've also been working with Helmut Ermann and the Phonak FM team. One of the big challenges with FM is the adult market. The issue of whether FM improves signal-to-noise ratio (SNR) has never been in question; this technology has been available for some time now in schools and some social situations. Rather, the challenge is to overcome the stigma, inconvenience and cost of wearing and using FM in the real world . In essence, when a person wears hearing aids, she lets the world know that she has a physical disability. When she wears an FM device, however, she is actually forcing others to participate in that disability by requiring them to hold and/or use a transmitter. Baby boomers are less concerned than their parents are regarding the stigma associated with hearing loss, but their expectations for benefit are much greater. With Microlink, Phonak has developed an FM system that may be used conveniently and unobtrusively by hearing aid users in a variety of situations both inside and outside the classroom.

AO /Beck: Very good. Let's go back a step or two and talk about hearing aid shell technology please. I heard the terms Nemotech and eShell , and wonder if you could please explain them to me?

Fabry: Sure. Essentially, eShell is the product of the Nemotech process, which comprises the digital scan of the earmold impression, RSM, and the actual nylon eShell. We have spent the last year working to standardize and optimize the Nemotech process to ensure that it is more accurate, reliable and efficient than the conventional UV shell technique.

AO/Beck: Can you tell me based on clinical outcomes or analysis that you've done, have Nemotech and eShell impacted sales and return rates?

Fabry: We've tracked both of those. The Nemotech process has been used in the United States for well over a year, and has been available in Europe since October. Our primary focus has been to perfect the process prior to making wholesale changes in the way we make all of our shells, but we have seen Nemotech sales increase steadily. Perhaps the best indication of our success is the low remake rate when compared to UV shells, and also the number of customers who convert from UV shells to eShells. Both measures provide reason for optimism. That said, this situation is similar to the one with digital acoustics; until we use digital mechanics to improve the process beyond what is available with existing (UV) technology, there is no reason to expect revolutionary changes. We need to investigate other shell materials, ways to improve occlusion and feedback, and reduce the problem of moisture with hearing aids. Nemotech can address many of these issues. And, of course, there is the brass ring .

AO/Beck:
The brass ring?

Fabry: Elimination of the ear impression entirely. Clearly, if an accurate scan could be made of the ear directly, we can begin to provide benefits to the clinician and the end-user. Although this is an inevitable goal, it is still a few breakthroughs away, in terms of cost, accuracy, and feasibility.

AO/Beck: I understand. Let's talk about directional microphones. What is the state of the art right now?


Fabry: I think that if you look at the Marketrack survey that Kochkin continues to prepare, digital alone doesn't resolve and improve satisfaction with hearing aids. In fact, the strongest factor related to improved customer satisfaction with hearing aids is directional microphones. Along with FM devices, they are the only things that significantly improve signal-to-noise ratios in noisy listening environments. For that reason we continue to expend quite a bit of energy on those technologies. Just about every one of the major hearing aid manufacturers has good directional microphone technology, and so getting back to your question, the state-of-the-art is probably directional microphone arrays that change polar patterns in response to the speech and noise in the environment. They adapt their polar characteristics on the basis of whether a noise source is fixed or moving.

AO/Beck: And I believe that same technology is now being incorporated into cochlear implants?

Fabry: It is indeed. The Microlink device has become the industry standard for FM systems for hearing aids and for cochlear implants, and I think that we will see more sophisticated directional microphones on cochlear implant processors in the future as well, with the movement towards behind-the-ear (BTE) external processors.

AO/Beck: What is the smallest instrument you can get that would have a true directional mic?

Fabry: You can get a directional microphone in half-shell and in-the-canal shells now. When you start talking about smaller sizes, the benefits diminish because fewer pinna and concha resonances and directivity benefits are lost with these smaller styles, even for omni-directional microphones. But very good directional benefits are available in half-shell devices.

AO/Beck: In an ideal situation, what would typical directivity index numbers look like, to show the amount of directionality when comparing a BTE and an ITE?

Fabry: It depends a little bit on the location of the microphones, but from the standpoint of getting a front and rear-facing microphone you can theoretically get a little bit better performance from a BTE with directional microphones. The fact is, that the magnitude and the actual real world benefit has been shown to be comparable between BTE and ITE directional microphones. Remember too, the magnitude of the benefit varies across frequency.

AO/Beck: I was thinking you could expect about 4 dB or so on an ITE and up to about 6 ½ or 7dB on a BTE?

Fabry: Maybe not 7 dB from a BTE, but you're right, you would expect a little better performance from a BTE under typical listening situations. Keep in mind that this measurement depends on the location of speech and noise, the amount of reverberation, and the test signal. Certainly the wow effect is greater from a BTE than an ITE and I believe that's because the pinna in an unaided ear actually gives you a little bit of natural directional benefit to begin with.

AO/Beck: Okay, very good. Let's discuss FM for a moment. MicroLink has pretty much dominated the market as the standard, but there are other manufacturers involved with FM products and they make similar products. Can we expect new FM products in the near future, and will they be smaller and less expensive? Despite the obvious and impressive benefits of FM technology, FM remains cost prohibitive for many people.

Fabry: Yes. I think there are going to be exciting developments in FM systems with respect to size, power consumption, transmission range, and frequency compatibility across different systems. All of these will make FM use in the classroom much easier. But I think the bigger market for FM will be outside the classroom. FM systems are the next big thing in terms of tangible sound improvements, like directional microphones in noisy listening environments.

The problem has traditionally been that FM is okay as long as you're dealing with a single talker and a single listener but when you want to use the environmental microphone in addition to the FM microphone, the advantages of FM begin to diminish.

AO/Beck: Yes, I think that's correct, and I think that has been a source of frustration for patients and professionals.

Fabry: I agree. FM benefits exceed directional microphone benefits, but there are significant cost issues, both economically and with respect to the gadgetry that people have had to employ to benefit from FM. I think what we'll see in the years ahead is that when we can incorporate the FM chip into a hearing aid without having to couple extra hardware to it that will be when the nuisance factor depreciates considerably.

AO/Beck: I think that's a big part of it. The nuisance factor is not trivial, and FM currently requires additional effort, hardware, and switching the FM on and off, and you have to be real careful with the small components because they do get lost. These are two issues that make it difficult to use FM with children, even though the acoustic benefits are apparent.

Fabry: Exactly. Kids might swallow them, throw them down the toilet or lose them.

AO/Beck: Do you anticipate FM technology will become less expensive or are we at a price point that will remain fairly constant, but perhaps we'll get more for our money in the future?

Fabry: Well I think cost certainly is an issue and it prevents a lot of people from using FM. Phonak is trying to come up with the most efficient means of producing the product, and obviously as the quantity increases, the price decreases. If you compare FM technology to the cell phone industry for example, where they're able to make many, many more units, the single unit price comes down considerably. Unfortunately, we're just not at that point yet where the number of unit sales has significantly impacted the unit price.

AO/Beck: Thanks for the update Dave. I appreciate your time and willingness to discuss these issues with us.

Fabry: Thank you too, Doug. I appreciate the opportunity to address your readers, and I thank you for the opportunity.

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Dave Fabry, PhD

Director of Clinical Research

David Fabry is Director of Clinical Research for Phonak Hearing Systems in Warrenville, Illinois.  Previously, he worked at Mayo Clinic in Rochester, Minnesota, from 1990-2002, and he served as Director of Audiology from 1994-2002.  Dave served on the American Academy of Audiology Board from 1997-2003, and was President of the Academy from 2001-2002.  He is a past editor of the American Journal of Audiology, and is a member of numerous professional associations.  He lives in Rochester, Minnesota with his wife, Elizabeth, and his daughter, Loren.



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