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Final Word

Final Word: When Technology Bites Back

Van Vliet, Dennis AuD

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doi: 10.1097/
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Hemera Technologies

Talking with other clinicians, I frequently hear that patients are happier than ever with today's hearing aids because of their improved performance and cosmetics. Working with patients, I hear the same thing, but occasionally find that the features that help make hearing aids more comfortable and effective can work against us and get in the way of a good fitting.

Dennis Van Vliet, AuD

Feedback reduction has been one of the greatest improvements in hearing aid fitting in my decades of dealing with hearing aids. Managing feedback removes much of the worry that many patients have about wearing hearing aids and being embarrassed or annoyed by an untimely squeal. How the technology accomplishes the reduction is important, however. Some systems preserve the gain needed for audibility while others cut the gain temporarily or permanently to reduce the feedback. It is important to understand the approach to make sure that the technology supports our fitting goals.

No matter how the feedback reduction is accomplished, it is no substitute for skilled craftsmanship. Comfortable earmolds or shells that stay securely in place and provide an appropriate seal are a hallmark of properly fit hearing aids. If the feedback manager masks the symptoms of a proper fit, we may not be providing the necessary customized fit needed for a successful fitting that lasts for months rather than weeks. I love the freedom that good feedback reduction systems offer; I just want to make sure the fitting is the best it can be initially, and then made even better with the feedback manager.

Directional microphones are the single feature on hearing aids that can improve the signal-to-noise ratio and therefore improve speech understanding in noise. Improving this is a primary goal of most hearing aid fittings, making this feature extremely important. Offering them as a selling feature to patients can be a disadvantage if the user expects too much or doesn't use them properly. Depending on a dynamic deployment of the directional microphone based on a computer-switching algorithm may not be the best approach for many patients because the algorithm simply cannot predict what may be the most important signal for all patients in all environments. Manual switching may still be the best way to use this technology to ensure that the user is getting the intended benefit.

Directional microphone elements such as low frequency reduction in directional mode, switching time constants, and adjustable polar plots may prove to be helpful depending on the patient and the environment. As the fitters, we need to be very clear on the adjustment parameters and how best to tailor them to the patients' individual needs.

Noise reduction has a seductive name. Dealing with the noise problem is the Holy Grail of hearing aid fitting. If we can reduce or eliminate the perception of noise along with amplification, patients should be much more accepting of hearing aids. Recently, I had two patients describe dissatisfaction with noise reduction settings in their hearing aids. One was 11, the other 78, but their words were similar.

Both said they were hearing well until they found themselves in a car with the typical road and mechanical noise that accompanies a moving automobile. They were describing the result of slow-acting noise reduction in flagship products of two different hearing aid manufacturers. They complained that the hearing aids turned down the volume so they couldn't hear what they wanted. The issues were resolved with adjustment, but the example illustrates that a feature designed with patient comfort in mind may not meet the goals of understanding speech in noise unless the feature is carefully deployed in concert with other components of noise reduction such as expansion, directional microphones, and fast-acting noise reduction.

The Final Word? Hearing aid technology has improved dramatically in the past decade, and we see new improvements with each cycle of new products that come with increasing frequency. Yet we generally have not seen changes in the average age of new users of hearing aids, nor an increase in those in need acquiring them. Where is the disconnect? The answer is that technology will not solve our problems. It is a tool that helps us do our job better, but it is still a job that requires skill and serious cognitive effort to get it right. If we expect to provide better hearing to a larger segment of the population who needs it, we need to look beyond technology.

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