Dr. Ross on Hearing Loss
Expectations, Hearing Aids, and Aural Rehabilitation
by Mark Ross, Ph.D.
Audiology Centers often see older clients who are, figuratively, being dragged to the center kicking and screaming. They don’t want to be there and, one way or another, they make their displeasure known to all. They’re at the center only because of the persistent nagging of their children, who insist that they need a hearing aid. They will then respond that they’re hearing just fine, particularly if everyone will only “stop mumbling.” While this conflict between generations may seem trivial and is sometimes laughed at, it is not a joke. Both parties feel somewhat aggrieved. One may sincerely feel that he or she basically hears fine; but underlying this façade there is also probably some apprehension regarding the consequences of accepting the reality of a hearing problem and getting a hearing aid (i.e., cost, the need to adjust to something new, etc.). The adult children, on the other hand, sincerely want to help their parent. They can cite specific instances when their parent misses out on everyday verbal interactions, and they see the parent becoming increasingly socially isolated. They’re acting out of love and concern.
Faced with such a situation years ago, I tried to resolve it by asking the client (an elderly woman) and her adult daughter to each complete a rating scale that assessed communication abilities. One scale was designed for self-assessment, in which the client rated his/her communication difficulties in various situations. The other scale was a parallel version, designed to be filled out by significant others, in this case the daughter. In other words, the two forms examined the same communication situations, but with a slight change in wording for first person and third person ratings. Optimally, the scores in the two versions should be similar if not identical. When we looked at the results, however, it almost appeared as if the ratings pertained to two separate people. The ratings completed by the client of her own experiences essentially denied the existence or the severity of hearing problems in a number of situations, while the one completed by the daughter noted severe communication difficulties under these same conditions.
The widely conflicting results reveal how the perception of the impact of a hearing loss can differ dramatically between the hearing impaired person and a significant other. This can lead to erroneous expectations of the benefits a hearing aid can offer. The “significant other” may expect something close to normal auditory functioning (“once she has a hearing aid, she’s going to hear perfectly fine”); the fact that this assumption will prove to be erroneous is often grounds for disappointment and further conflicts (“you’re not trying hard enough”). The client, on the other hand, will often find that hearing aids offer unexpected help in a number of situations (though they are sometimes reluctant to acknowledge this fact). The use of standardized pre-fit and post-fit rating scales, by both the client and the significant other, provides a common ground for a comparison between the differing perceptions. Hopefully, this will help reconcile the faulty expectations of in both parties.
The Performance-Perceptual Test
A conflict in expectations may exist not only between the person with a hearing loss and his or her conversational partner(s); it can also be present within the individual. There is often a disparity between how a person believes he/she is hearing and how he/she actually does hear. There are people, for example, who think that they hear particularly poorly in noise but who - on objective tests - demonstrate relatively good ability to understand speech in the presence of background noise. Others (relatively few) are just the opposite; these people believe that they hear pretty well in noise, although the results of speech tests demonstrate that in reality they do very poorly. Both situations will lead to erroneous expectations regarding listening performance with a hearing aid. People in the first group are overly pessimistic, thinking that they do much poorer than they actually do, while those in the second group are unduly optimistic, in reality doing much poorer than they think they are doing. Both groups require a reality “re-calibration” in order to have realistic expectations regarding hearing aid performance. The recently developed “Performance-Perceptual Test (PPT) by Gabriel Saunders and Kathleen Cienkowski can help do just this.
The performance portion requires that 20 short sentences be presented in the presence of a constant background noise, with the subject having to repeat each sentence. The procedure requires that the intensity level of the sentences be decreased until they are no longer intelligible, and then increased until they can again be understood. The sentences are scored for accuracy after each presentation. In this manner, the noise is ultimately bracketed by the sentences, with half of them understood and half not. The final score is the average intensity of the last six sentences relative to the constant background sound. The resulting metric is the speech-to-noise (S/N) ratio, and it indicates the relationship between the speech and the noise levels at which a person can understand 50% of the speech material. (Audiologists will recognize this as the Hearing in Noise Test, or HINT).
For example, if the background noise was a constant 60 dB, and the average intensity level of the last six sentences was 64 dB, the resulting S/N ratio would be +4 dB. (We should understand that each dB on this type of test translates into about an 8- 10% difference on a conventional speech discrimination test, so these tiny numbers are significant.) The test itself takes only a few minutes to administer, but it can provide important insights regarding how a person understands speech in noise.
The next part of the PPT, the perceptual component, follows exactly the same procedure albeit with a significant difference. In this portion, the subjects are not asked to repeat the sentences but simply to indicate whether or not they understood each sentence as it was presented (yes or no). In other words, in the first portion of the test, their comprehension is actually being measured (performance); in the second portion, it is the perception of their comprehension that is being obtained. Both portions of the test, however, use the same test lists and follow the same test procedure. This makes the relationship between these two scores directly comparable and potentially very useful. While others have reported on the frequently observed difference between a person’s perception of his/her performance and the actual performance, this is the only test that permits a direct comparison. And, like the first portion, it takes only a few minutes to administer.
Generally, for people with normal hearing, their perception of how they perceive speech is aligned with their actual performance. Their scores on both portions of the PPT are essentially the same. That is, they actually do about as well as they think they do. This is also true for most people with hearing loss; they are also very well aware of whether or not they understand a speech message. However, there are many people with hearing loss whose judgment of their ability to comprehend speech in noise is poor. Either they think they understand speech in noise much better than they do (overly optimistic) or they actually do much better than they think they can (overly pessimistic). In any case, a successful hearing aid adjustment may be jeopardized because of erroneous expectations. In order to deal effectively with a significant mismatch between perception and performance, the audiologist must know whether and how much a client is being overly optimistic or overly pessimistic regarding his or her ability to understand speech in noise.
A Functional Communication Assessment
It is a truism of clinical management that in order to deal effectively with any condition, one must first learn all one can about it. This is not done as well as it should be when it comes to hearing aids. When people arrive at a hearing aid center, everyone’s focus tends to be on the “product” (the hearing aid) and not the hearing loss or communication problems that brought the person there. The explicit goal then becomes the selection of a hearing aid, with the implicit assumption that this will “solve” the communication problems. But while a hearing aid is necessary (no dispute there), it is - more often than not - insufficient. In spite of all the claims of the appealing marketing ploys we are continually exposed to, there is more to helping someone with a hearing loss than providing a hearing aid, no matter how advance it might be.
A hearing loss affects different people differently. There are people for whom a mild to moderate hearing loss can have major consequences, on both their quality of life and their perception of a handicap. The hearing loss may permeate every aspect of their lives. Other people with a similar degree of hearing loss may report that it has little impact on their daily life. Who is right? They both may be. But we should know the difference. People come to the hearing aid selection process with different communication needs, different experiences, and different personalities. It follows that in order to effectively manage the consequences of a person’s hearing loss, the full scope of its impact must first be understood. An audiometric evaluation will give us only part of the story.
In a recent article in The Hearing Journal, Dr. Robert Sweetow presented a convincing rationale for embedding the hearing aid selection process within a total communication matrix, which he terms the “assessment of functional communication ability.” He suggests that the hearing aid be selected only after a full battery of subjective and objective tests is administered. This need not be a lengthy process. Most of the tests he recommends take only a few minutes to administer. The results, however, can help ensure that a person will obtain the maximum benefit from hearing aids, and furthermore, that he or she will be satisfied with the benefit that has been achieved. The recommended measures include both objective and subjective measures.
What the subjective measures have in common is that they utilize a self-assessment procedure. Here, people rate how the hearing loss has affected them in various ways, for example in the communication, social, and emotional spheres. This type of scale will help the clinician, and the individual, to better understand how the hearing loss has affected that specific person’s life. Without this kind of information it is impossible to determine whether some sort of rehabilitative program is necessary and, if so, what its scope should be. In other areas covered by these subjective evaluations, people will rate the specific areas in which they hope a hearing aid will help them improve their communication skills (i.e., hear better in staff meetings) and their overall communication ability in a number of situations.
In addition to the traditional audiometric examination, the functional assessment plan envisions objective testing of speech perception in noise (such as the test described above), the ability to tolerate noise (acceptable noise level, an important predictor of hearing aid “success”), and a test of binaural interference (some, relatively few, people are not candidates for a binaural hearing aid fitting).
The two tests of speech perception in noise that Dr. Sweetow includes in his suggested battery result in a score that may be unfamiliar to most hearing aid users. Instead of a speech discrimination score of, for example, 80 % (quiet or noise conditions specified), the results are shown as a speech-to-noise (S/N) ratio, as in the Performance-Perceptual Test reviewed above. This is a particularly useful way of demonstrating a person’s ability to comprehend speech in the presence of background noise. The test can be administered rather quickly and the scores can be compared to those obtained by other people with hearing loss, across different hearing aids, different amplification and training conditions, and over time for the same individual. These tests are recommended by national professional organizations and it is unfortunate that they are not yet routinely included as a component of every audiological evaluation.
The results of both the subjective and objective portions of the assessment are used to develop an individualized communication enhancement plan. This plan reflects the reality that it takes more to resolve the problems and issues wrought by a hearing loss than just a focus on the hearing aid itself. It recognizes the differential effects of hearing loss on different people, and that these differential effects must be addressed in a specific fashion. The information collected during the functional communication assessment can be used to create a personalized aural rehabilitation program for the person. In addition to well-fitted hearing aids, this can include recommendations for other types of hearing assistive technologies (i.e., alerting and warning devices, personal FM system, etc.) a home or clinic communication training program , a personal or group workshop on “living with a hearing loss,” and information and counseling regarding the hearing loss.
The point is that hearing aid selection must not be seen as an isolated activity, but as a component of an overall aural rehabilitation process. A hearing aid is more than some technologically sophisticated electronic appliance; it is not just some device that one can purchase as one would buy a toaster or a TV set. A hearing aid signifies that the person, somehow and somewhere, had been having communication problems; these kinds of difficulties can strike at the heart of what it means to be a human being. And its impact upon the specific personality and requirements of an individual cannot be ascertained without an effective assessment procedure, to be followed by appropriate aural rehabilitation measures. Then, and only then, can the issues created by a hearing loss be resolved as fully as possible.