Dr. Ross on Hearing Loss
What You Should Expect From Your Hearing Aid Dispenser
by Mark Ross, Ph.D.
The sense of hearing is undoubtedly one of, if not the most important sensory faculty that human beings possess. It underlies the effortless manner in which normally hearing children develop speech and language; it provides the conversational basis for effectively communicating with other human beings; it serves to give us access to the wonderful world of music and to the sounds of nature; and it alerts us to the presence of potential danger. Because it is so universal and so taken for granted, the potential impact upon people who develop a hearing loss is often grossly underestimated. We see evidence of this in the casual and inefficient manner in which hearing aids are frequently provided for people with a hearing loss.
A hearing aid is not just another “product,” akin to some household appliance; it is, rather, the most important tool available for minimizing the effects of a hearing loss. In recognition of this fact, the American Speech-Language Hearing Association (ASHA) and the American Academy of Audiology (AAA) have published detailed guidelines pertaining to the fitting of hearing aids. These guidelines represent the consensus view of the leading Audiologists in the country. In general terms, they outline what factors and procedures should be included, or considered, when selecting hearing aids for some particular individual. I will base much of what I will be saying on the content of these guidelines (mainly those from the AAA, as they are more recent).
To supplement the interview, the dispenser should ask the person to complete one or more self-report questionnaires (which can be completed at home or in the waiting room). These are designed to systematically assess how the individual views the psychosocial and communicative impact of the hearing loss, to focus in on specific areas of hearing difficulty, and to gain some insight into the person’s expectations. Together with the information gathered during the initial interview, this information should help the dispenser select the type of hearing aid and/or hearing aid features that may be the most helpful. Some questionnaires are designed to be re-administered during a follow-up visit, so that the self-report results can be compared to those obtained initially. This comparison can suggest the need for further hearing aid “tweaking,” communication therapy procedures, or, hopefully, indicate that the real-life handicap of the hearing loss has been greatly reduced.
A comprehensive audiological evaluation should be conducted on every potential hearing aid candidate to determine the type and extent of the hearing loss. A simple pure-tone audiogram, though necessary, is not sufficient; that does not constitute “a comprehensive audiological evaluation.” There are a number of other potentially useful hearing tests that should be considered, including those that ascertain one’s ability to comprehend speech in noise or determining whether there are cochlear regions in which the hair cells are damaged or dead; such measures have direct application to the hearing aid fitting process. One test that is too rarely conducted, but which is recommended by both ASHA and the AAA, is the measurement of loudness discomfort levels (LDL) on a frequency- by- frequency basis. The purpose of this test is to ensure that the hearing aid output does not produce uncomfortably loud sounds. This is one of the first, and certainly one of the most important, lessons new students are supposed to learn during their training. I say “supposed to learn” because recent surveys still show that about 50% of hearing aid users are not satisfied with their “comfort with loud sounds.”
Instead of measuring the loudness discomfort level directly, what many dispensers do is base their estimate of discomfort levels on the person’s hearing loss thresholds. While a general prediction of this relationship can be made – between a person’s thresholds and the sound level at which sounds become uncomfortably loud – this relationship does not apply to all individuals. We know that people with similar degrees of hearing loss can differ considerably in their tolerance for loud sounds; what many individual hearing aid dispensers do, however, is to simply enter a person’s thresholds into the hearing aid fitting program and then depend upon the program to display the recommended amplification characteristics of the hearing aid. The accuracy of this procedure has repeatedly been discredited by research, but it still continues.
Two fairly recent studies, one conducted in the United States and one in Canada, convincingly display the potential pitfalls underlying this procedure. In both of these studies, the same audiogram was entered into the hearing aid fitting program for six (U.S.) or nine (Canada) different hearing aids. We know that a person’s basic amplification requirements should not change simply because he or she is wearing different hearing aids; these requirements are set by the person’s auditory pathology and not by the hearing aids. It follows, then, that the recommended basic response pattern of the different aids should be the same, or quite similar, for the identical audiograms. However, the research results in both countries contradict this plausible expectation. The researchers found wide variations (as much as 15-20 dB) in the recommended responses. While these aids may differ in other respects, and probably do, in this basic function of hearing aids – making sounds audible across frequency – they all suggested different starting points. Clearly, they all can’t be right. As it happens, about 70% of hearing aid dispensers use the manufacturer’s suggestion as their first fitting option. Hopefully, during follow-up visits, dispensers will examine this initial choice more carefully and make such changes as are needed - but we don’t know how many actually do this.
The most accurate method available for ensuring both maximum usable audibility while avoiding uncomfortably loud sounds is by using a probe-microphone in the ear canal to measure the aided performance of a hearing aid (“real-ear” measures). Other measures are helpful, but not as conclusive. The graph we see on the screen of a hearing aid programmer informs us of the performance of the hearing aid’s electrical circuitry; when a hearing aid is tested in the coupler of a hearing aid test box, the display tells us how the aid would function in some “average ear”; only a real-ear test reflects the hearing aid’s overall performance in a specific individual’s ear. Unfortunately, it appears that only about 25% of hearing aid dispensers routinely include real-ear measures as part of their hearing aid testing protocol. (The figure in Canada is much higher, about 63 %.) The AAA recommends that real-ear measures be obtained during both the initial selection and the verification stages as important components of the hearing aid selection process.
In recommending a specific type of hearing aid, the dispenser must consider not only the results of the audiometric tests but also the client’s individualized communication difficulties and needs, cosmetic sensitivities, ability to physically manipulate tiny controls, etc. Modern hearing aids come with a host of special features; the potential value of any feature must be weighed against its additional cost. This needs to be explained to the consumer. We can think of this stage as a kind of negotiation between the dispenser and the client. Personal preferences must always be considered, but may need to be modified by the reality of the hearing loss and the professional advice given by the dispenser. What should not happen is what Consumer Reports found in a recent survey (July 2009): that nearly half their shoppers were not offered a choice of hearing aid style. One shopper reported, and this is an experience I’ve heard time and again, is that the hearing aid dispenser simply assumed that someone would prefer the “nearly invisible” Completely-in-the-Canal hearing aid (at a somewhat higher cost, I might add). In such instances, the dispenser is assuming cosmetic preferences that in fact may not exist.
Another crucial stage in the process occurs after specific hearing aids have been selected. Hearing aid users must understand the operation of their hearing aids. It is the responsibility of the dispenser to, at the least, begin this educational program. Consumers should not leave a dispenser’s office until it has been demonstrated that they can insert the hearing aids correctly, change the batteries, manipulate the volume control, know when and how to use a telecoil, and are informed of the operation of the special feature contained in the hearing aid. While many of these features operate automatically, (e.g., feedback suppression), others do not. Nevertheless, automatic or not, hearing aid users should know at least the general purpose of any special feature in the aid that they will be using.
In short, lots and lots of information has to be conveyed to the user, much more than can be absorbed in one or two visits. The reality is that much of this information is immediately forgotten or recalled incorrectly several months later. In an article published several years ago, the efficacy of health- related informational counseling was examined. It turns out that about half of the information had been forgotten the moment the client stepped out the door and half of the remainder was recalled incorrectly some months later. Clearly, there is a need to improve the consumer’s comprehension and retention of this kind of information. Just about all hearing aid dispensers will provide their clients with printed material that reviews and extends the information conveyed during their face-to-face encounters. It is the responsibility of every hearing aid user to read and to try to learn this material. This is a point worth stressing: Consumers have an obligation to be more than simply passive recipients of a dispenser’s services. In turn, it is the responsibility of the dispensers to respond to any of their consumers’ questions (either during follow-up visits or telephone contacts).
A hearing aid user should expect at least one scheduled follow- up visit, and as many more as are deemed necessary, during the thirty- or sixty- day trial period. Often a number of “tune-ups” may be necessary, and questions and observations may arise that need a response from the hearing aid dispenser. Consumers who decide to return the hearing aid should expect to pay a cancellation fee of 10 % or 12 % of the purchase price. After the trial period, and as part of the initial purchase agreement, at least two more follow-up visits should be scheduled during the following year. But above all, what consumers should expect from their hearing dispenser is time - time accompanied by patience and skill. Indeed, according to hearing aid dispensers, the need to spend a great deal of professional time with a client is a major reason that hearing aids are so expensive. And yes, there is convincing evidence that personal satisfaction with hearing aids do increase as a dispenser spends more time with a client.
Remember- most new hearing aid users are entering a new world. While there are many similarities in the experiences and management of all hearing aid users, there are many differences as well. And new users need a knowledgeable guide when they enter this new world. In spite of the many advances in hearing aid technology and in the movement to provide initial and follow-up services via the Internet, there is no substitute for the personal touch. This can be most effective when taking place in group, multi-session formats, during which people can share their experiences as they review the material presented during their individual sessions. This can include previously covered material (i.e., the audiogram, care of the hearing aid, intro to speechreading, etc.) as well as an introduction to other material not previously covered or covered just superficially during the individual sessions (i.e., hearing assistive technology, communication repair strategies, home-based training programs, etc.). In any event, no matter how these informational sessions are structured, consumers should expect their hearing aid dispensers to focus more broadly on the problems and implications of the hearing loss, rather than just on the hearing aid itself. In short, the hearing impairment should be treated with a full and sensitive understanding of the importance that the sense of hearing plays in our lives.