Revisiting the Perennial Question: What is the "Best" Hearing Aid? - Part Two

By Mark Ross

Editor: Such a simple question. Such a complex answer! Here's Mark Ross with his thoughts on the best hearing aid.. This article was originally published in the January/February Issue of Hearing Loss magazine, and is reprinted with the author's kind permission.

This is part two of two parts.

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February 2009

Here's Part One

About all we can say that people with hearing losses have in common is that they all have hearing losses! I don't mean this to be a facetious comment, but sometimes we seem to overlook this basic fact. In reality, it is not just a question of someone falling into the generic category of having a "hearing loss," but the type, nature, and severity of the auditory disorder displayed by the specific person. This will have major implications in determining what kind of hearing aid the individual should use and how well he or she does with it. We're all somewhat to very familiar with the basic dimensions of a hearing loss, as visualized in an audiogram. From this chart, we can see how much of a hearing loss a person has across the frequency (pitch) range. The pattern displayed by an audiogram can very considerably between people, with probable significant behavioral implications for the larger variations. Generally, for example, a person with a severe high frequency hearing loss will not function in the aided condition as well as someone with a moderate flat hearing loss (equal hearing loss at the different frequencies). In other words, the same hearing aid will not result in equal performance for these two people. This occurs because the upper limit of possible performance is set by the nature of the auditory disorder and not the hearing aids; because people differ in the severity and nature of their hearing loss, so will their hearing aid performance.

The information provided by an audiogram, as crucial as it is, presents us with only the most superficial information we have about the components of an auditory disorder. Two people with exactly the same audiogram may, and often do, demonstrate completely different listening performance in other auditory tasks, such as their loudness discomfort thresholds and speech comprehension in noise. For example, one such person may find the limits of acceptable loudness to be 80 dB, while the other person with a similar audiogram finds that sounds of 100 dB are easily tolerable. These different tolerance limits will affect the how a hearing aid is fit and how successfully a person performs with it. Such individuals may also differ considerably in how well they understand speech in the presence of noise, though there may be little difference in their speech perception scores in quiet. In other words, auditory disorders and their observable consequences encompass more than what is displayed on the audiogram. These would include, among other dimensions, the ability to detect small time differences within and between speech sounds (temporal resolution) as well as their ability to separate out the individual components in a complex sound (frequency resolution).

Differences in these dimensions explain why hearing aid users with the same audiogram and the same hearing aid may perform differently. But the question still remains; given the nature of some specific individual's auditory disorder, is there a best hearing aid (or amplification pattern) for that particular person? Certainly, we know from experiences garnered by consumers and professionals over the years, people do perform better, or worse, with one amplification system over another. But is the hearing aid a particular person is now wearing, or contemplating purchasing, the absolute best for that person? I don't know and furthermore I don't think the question is answerable at this time, for this reason: we have no way now of determining what a person's potential speech perception capabilities are to which we can compare his or her actual performance. How do we know when we've reached the best possible performance? Additionally, given the awesome flexibility now incorporated in modern hearing aids is it possible that the consumer would do even somewhat better if one or more of the hearing aid's electroacoustic dimensions were varied in some fashion? I'd say the possibility exists, but there is no way at the present time that we can be certain.

It seems to me that rather than focus on the best hearing aid, potential hearing aid purchasers could more fruitfully spend their time and energy looking for a well-trained audiologist, one who is competent, caring, and conscientious. This is the person whose job it is to select the "best" possible amplification system for a hearing aid user, one who can maneuver between the myriad possibilities now offered by modern hearing aids. Such a person will not only keep up with new developments, but also not limit their efforts to the device itself but will also consider and respond to the totality of a person's communication problems. The hearing aids these people recommend should ensure that their client's performance falls into the best possible "zone" of performance, one consistent with the person's hearing loss, the audiologist's personal experiences and the research evidence.