Dr. Ross on Hearing Loss
State of the Science on Aural Rehabilitation
by Mark Ross, Ph.D.
The Rehabilitation Engineering Research Center (RERC) on Hearing Enhancement held a national conference on Aural Rehabilitation September 17 through September 20, 2006 at Gallaudet University. This was designed to be a “State of the Science” meeting, in which the latest information on all aspects of Aural Rehabilitation (AR) was presented to an audience composed primarily of practicing audiologists, researchers, and university professors. The presentations included papers on evaluations, various kinds of training procedures, efficacy of some hearing aid features, and a review of theoretical considerations underlying performance with cochlear implants. The last day was entirely devoted to topics concerning people with dual sensory loss. The scope and sophistication of the papers clearly reflect evidence of a maturing profession, one that is able to examine a topic as amorphous as aural rehabilitation with scientific rigor.
To ensure the inclusion of the human side of AR, a panel was convened daily, and people with various degrees of hearing loss and dual sensory problems had an opportunity to recount the challenges they faced in their lives and the kinds of changes they hoped could take place in the near future. The panelists did not hesitate to criticize what they felt to be inadequate or insensitive professional services. Thus, the audiologists in the audience could hear how “the other side” felt and how they viewed the professional community. The issues and information presented covered the entire gamut of AR, and it would be impossible for me to summarize it all here. Rather, I would like to make some personal comments about the AR process, while referring to just some of the topics and conclusions made in a few of the papers.
It is generally agreed that AR began during and immediately after WW II. Faced with a large number of newly deafened servicemen, whose hearing losses could not be treated medically or surgically, the military services organized AR programs in a few military hospitals around the country. Money was not an issue, or at least not a major one (very different from nowadays!). What “the boys” needed, they got. The military brought together specialists in a number of areas, such as medicine, acoustics, psychology, speech correction, deaf education, and lipreading. These specialists were tasked with the challenge of organizing an optimal AR program. It was basically an “a priori” judgment, since there were only a few people with AR experience with whom these people could consult. Although “schools” and methods of lipreading had existed in the US and Europe since the late 1800s, little or no objective information existed about the efficacy of the various procedures that had been developed. So the specialists used their best judgment and included what, on a logical basis, appeared to be the necessary components of an ideal AR program.
At the time lipreading and auditory training constituted just about the entirety of what was thought to be AR, so these were the areas that were stressed. However, unlike the lipreading programs of earlier years, wearable electrical hearing aids were available in the l940s, and their selection and use was included in the planning and became an important component of the program. The inclusion of hearing aids necessitated the development and utilization of somewhat more sophisticated audiometric tests than those that were generally employed by ENT physicians. Later, the field of Audiology, whose genesis can be traced to the AR programs organized during WW II, would stress this ”scientific” aspect of rehabilitation activities more than any other component. The AR component became, and in my judgment has remained, a bit of a professional “step-child” ever since.
These early pioneers did an excellent job and deserve an “A+” for their accomplishment. I can say this on the basis of personal experience. In early 1952, I was a patient in an AR program that had its inception during WW II. We lived at the hospital (the Forest Glen section of Walter Reed) for eight weeks while we attended classes full-time and underwent various audiometric and medical examinations. The selection, use, and care of hearing aids (monaural body aids) was included as an integral component of the program. Most of the time was spent on various lipreading and auditory training procedures, which were extensive and very creative and included memory span exercises, cognitive training, and lots and lots of lipreading practice. Except for some informal evaluations, I do not recall being given any type of objective measure regarding our lipreading prowess. I do know that all of us patients felt that we were learning how to communicate more effectively. I’m confident that the instructors sincerely believed this also. On its face, the AR program clearly had a great deal of merit. I, personally, will always be grateful that I had the opportunity to participate in this program.
What we would now define as the psychosocial realm was not explicitly addressed in the training curriculum. However, in retrospect, it is clear that much of the value of the program undoubtedly rested on the informal interactions among the patients. The group experience, while undefined at the time and even unintentional, undoubtedly impacted on all of us there. The participants could share experiences, encourage acceptance of the reality of the hearing loss, and support reluctant new hearing aid users to “get on the air.” It was the kind of interactions that current AR proponents constantly seek to emulate, but find difficult for a number of reasons (money and acceptance being the key ones). Old-time lipreading teachers can testify how often their students would seem to get off track in their desire to use class time to exchange personal experiences; the wise teachers knew enough to encourage these interactions, recognizing their value. (These were the days before the term “speech-reading” became the approved terminology for the activity, and for very good reasons. We now know that achieving optimal visual communication clues depends upon more than just the lip movements.)
Alas, this “Camelot” of AR programs is no more. Over the years questions were asked regarding its cost-effectiveness, and evidently the answers were not very satisfactory. We have, it is quite apparent, moved into a more budget-conscious era than existed during WW II. Rehabilitation endeavors in all areas now stress objective evidence regarding the efficacy of therapeutic procedures. This requirement is particularly important to third party funders of rehabilitation therapies, whether the Pentagon or private insurance companies. And the evidence required by the budget minders has to be convincing and irrefutable; they are not known for being eager to approve the expenditure of funds. The burden, therefore, is on the provider of AR services to prove their efficacy. My personal testimony as a patient, no matter how convinced I am of the value of the services I received - or have provided others – is insufficient. Along with all other types of therapeutic procedures, AR now has to be placed on a defensible, scientific, footing. The presentations given at the State of the Science Conference met this requirement. Some dealt with the results of therapeutic procedures, others were more conceptual in content; all, however, reflected the current state of knowledge in topics related to AR.
Up to now, I’ve talked about AR as if it were some clearly definable procedure. It’s really not. As I have already implied, years ago the term was used almost synonymously with lipreading (or speech-reading), with an occasional bow to auditory training. Courses at some universities were labeled “aural rehabilitation” and consisted primarily of lipreading lessons. The concept is much murkier now than it was then. But if we are to know what we are talking about, we have to define what we mean by the term. I would define AR as any device, procedure, information, interaction, or therapy which lessens the communicative, psychosocial, and economic consequences of a hearing loss. While this definition pretty much covers the waterfront – any casual hallway encounter can be labeled as AR if it is seen as helpful to a person - it doesn’t address the actual effectiveness of any rehabilitation measure. Thus, for example, while we don’t need to formally investigate the question of whether hearing aids are helpful to people (that is self-evident), we really don’t know how much, whether, or what type of post-selection training can increase the benefits and satisfaction of hearing aid usage.
Unfortunately, much of what is called AR is notoriously difficult to research, particularly in the psychosocial realm. But we don’t have the luxury of waiting until the emergence of irrefutable evidence before we do anything; people need help now. And as it happens, quite a bit is known about “best practices” in Audiology. Recently, the profession has published guidelines, entitled “The Audiologic Management of Adult Hearing Impairment” (Audiology Today, Sept/Oct 2006). These guidelines distill the essence of the current state of research evidence and clinical practices of leading audiologists in the field. They begin with the recommended components of an auditory assessment and end with suggestions regarding follow-up Audiologic Rehabilitation. In between, the guidelines cover the assessment of auditory and non-auditory needs, components of a hearing aid selection procedure, and hearing assistive technologies. It should be noted that this four- page published guideline is a summary of the complete forty-four page document. The presentations at the State of the Science Conference reflected much of the content of these guidelines. (As it happens, three of the AAA committee members who formulated the guidelines presented papers at the conference.)
One of the areas in which a “best practices” consensus exists is in the necessity to administer scales that look at the overall subjective impact of a hearing loss. We know that people with the same degree of hearing loss will react differently to it; for one person, the condition may be terribly handicapping, while another person may just shrug it off. But just as an audiogram is necessary in order to define a person’s hearing thresholds, so are subjective scales necessary to indicate how a particular person perceives the impact of a hearing loss on his or her life. How, for example, is communication affected in a host of real-life situations? Is employment or safety compromised? Are there social or emotional consequences (e.g., going out less, becoming more isolated, etc.)? A very fine review of these “outcome” scales was delivered by Harvey Abrams at the conference, which included ways to employ these scales to estimate the cost-benefit value of therapeutic procedures. Unfortunately, in spite of their potential value as clinical tools, only a minority of clinical audiologists routinely employ subjective outcome measures in their practice. The main objection evidently is that administering, scoring, and following through would simply take too much time (and many do not really believe that they are necessary, a contention that I would dispute).
A number of studies at the AR Conference implicitly or explicitly addressed the time factor. In one paper, by Cindy Compton-Conley and Claire Bernstein, a computerized system was described that will enable audiologists and their clients to navigate through a comprehensive communication needs assessment. The goal here is to determine the hearing technologies and strategies required to meet each client’s unique communication needs and to accomplish this in a cost-effective manner. The program would include specific hearing aid features (e.g., directional microphones, telecoils, direct audio input), other types of hearing assistive technologies (e.g., neckloops, personal FM systems, signaling and warning systems), , telephone adaptations required, and specific therapeutic procedures (e.g., various kinds of communication strategies). This still-evolving project aims to develop a system that can either be completed by a client in an audiologist’s office or can be done at home with the results transmitted to the audiologist.
The use of a computer was a primary component in other research papers that were delivered at the conference. Five presentations dealt with auditory or auditory-visual training, with each one using a slightly different approach. Several reminded me of the auditory training exercises I underwent over fifty years ago, based on a paradigm first described by Raymond Carhart, one of the founders of Audiology. This technique requires the recipient to discriminate between broadly different acoustic stimuli (like the vowels in the words /mat/ and /moot/); then slowly the sound discrimination task gradually becomes more and more difficult (e.g., discriminating between /beet/ and /bit/, or /deed / and /beed/bead). This procedure has been immensely refined since it was used years ago, and, as evidence presented at the conference clearly shows, can produce significant improvements in a person’s auditory skills. Additionally, because of the advances in neural imaging, it is now apparent that these training procedures can actually produce measurable changes in cortical neural activity. Indeed, one of the papers (by Emily Tobey) went even further and demonstrated pharmacologically enhanced responses to auditory training. I would rate these advances in auditory training as the most exciting AR developments I’ve seen in recent years.
I reviewed one of the auditory training programs discussed at the conference in a previous Hearing Loss publication (Nov/Dec 2005). This is the LACE (Listening and Communication Enhancement) program developed by Robert Sweetow at the University of California in San Francisco. Like the other papers on auditory training given at the conference, this one is computer-controlled and can be self-administered at home (more on this point later). LACE includes a number of sentence- and word-based listening tasks as well as various auditory-span and memory exercises. The full results and rationale for the LACE program have recently been published in the Journal of the American Academy of Audiology (September 2006). The positive listening and communication changes reported in the study are attributed solely to the auditory training and not to any change in hearing technology. The evidence clearly shows that auditory training does work.
An investigator from the House Ear Institute (Qian-Jie Fu) presented the results of a multi-faceted study on Perceptual Learning and Auditory Training in Cochlear Implant patients. He found that a moderate amount of daily training was effective in improving speech recognition. In his training program, he utilized both a phoneme- and a sentence-based approach and found that training on phonetic contrasts may also generalize to improved sentence recognition, but not necessarily the other way around. He made an explicit point of supporting the use of a computer-based auditory training program, one of which is available through the House Ear Institute (and is used by several cochlear implant companies). A version of the program (“Sound and Beyond”) was also reviewed in an earlier article in the Nov/Dec 2005 issue of this journal.
Arthur Boothroyd reported on the current status of a computer-assisted speech perception test and training program (CasperSent) that he has been working on for a number of years. He bases his procedures on a model of the speech perception process that considers sensory and contextual evidence, topic knowledge and skill (e.g., attention, speed, confidence, risk-taking). The training stimuli consist of sentences, which can be presented by lipreading, hearing, or the two in combination. One unique feature of this program is that presentation modality, viewing angle, response feedback, and topic knowledge are under software control. The program can be used either as a test program, to evaluate the effectiveness of other computer-assisted training programs, or as a training tool in itself (and, as such, has shown itself to be effective).
Another computer-controlled auditory training program was reported on by Harry Levitt. This employs a “tracking technique,” a therapeutic technique that has gone in and out of fashion for a number of years. The technique requires the subject to repeat sentences verbatim that are taken from a complete paragraph (to add contextual evidence) which has been delivered either through lipreading alone, hearing alone, or in combination. Errors are noted, various corrective communicative strategies are applied and taught, then the next sentence is presented, and so on. The problem with the technique has been the difficulty in controlling speaker and content variability. Harry Levitt describes how computer-based methods of tracking can maintain the interactive nature of the communicative process while bringing the major sources of variability under control. This technique is now being used to improve the communication skills of adult cochlear implant users and is being adapted for self-training applications employing recorded materials.
Taken together, these computer-controlled auditory/visual training programs suggest a way to escape the dilemma that has faced hearing-impaired consumers and audiologists since the WW II era. It takes time to provide any kind of AR program, from the imparting of information to actual face-to- face therapy encounters. And as we are continually being reminded in all areas (not just the health-related ones), time is money. Somebody has to provide these programs and somebody (or some entity) has to pay them for doing so. Unfortunately, it does not seem that AR will soon, if ever, garner the financial support from the health-care system that other forms of rehabilitation do (such as physical and occupational therapy and psychotherapy). Even if and when unimpeachable evidence of AR effectiveness is obtained, society does not view the personal impact of a hearing loss as having the same consequential effect as other physical or mental problems. And so a hearing loss “gets no respect.” People are, of course, free to pay for their own therapy, and some do, but this is not an affordable long-term option for most of the population with hearing loss.
However, the majority of our population does now has access to personal computers. The software programs described above can be self-administered by people with hearing loss in their own home, and at their own pace. The expense is minimal compared to an ongoing course of personal therapy. The most efficient and effective way to institute this self-training is with the assistance and cooperation of a consumer’s personal audiologist (or perhaps one of the “mentor” graduates from the RERC/Gallaudet training program). Several of the programs require, at least initially, that a user log on to a central site from which the audiologist can monitor progress and provide assistance when necessary. In the ideal world, the introduction of a home-based auditory training program would take place during a short-term, group AR program that would be routinely included as a component of the hearing aid selection process. Human beings still have a vital and irreplaceable role to play in the AR process; we’re not yet at the point where machines can replace people. But, still, the development of these computer-controlled programs portends a new model of AR, one that can be both cost-effective and practical.
A personal computer also was a key element in another of the papers delivered at the conference. People being fit with hearing aids have complained for years, and justly so, that the conditions in the clinic where the hearing aids were tested were completely unrealistic. Evidence shows that evaluations of hearing aids carried out in laboratory simulations of the “real world” will often overestimate the benefit that a hearing aid user will actually obtain. This project, carried out by Arlene Neuman, assessed the effectiveness of hearing aids in a real-world environment. To accomplish this goal, a small, wearable computer was developed and worn in a camera case that slips over a belt. The instrumentation included a small touch-screen and ear-level microphones. Overall, the set-up permitted simultaneous acoustic recordings of the environment and the output of the hearing aid, coupled with judgments about the perceived performance of the hearing aid in different listening environments. The eventual goal of this ongoing project is to increase a hearing aid user’s performance with hearing aids in multiple acoustic environments.
Various types of group AR programs were directly compared in a project presented by Jill Preminger. This was a very ambitious undertaking that attempted to determine the relative effectiveness of various types of AR programs and to see if any benefit was related to the personal characteristics of the participants. These group programs included structured discussions on emotional aspects of hearing loss, exercises in auditory and auditory-visual perception, communication strategies training, and informational lectures. Different groups of individuals received some combinations of these programs. The results (as measured via several subjective scales) did not demonstrate “robust” differences between the training groups and the control group. However, some individuals did appear to benefit from the training as measured by a clinically significant change on the self-assessment scale used in the study. The challenge is to determine who can benefit most from such training, what combination of procedures to apply, and to develop sensitive and appropriate measures to document any possible changes. It is studies like this that will ultimately lead the way to more refined AR procedures, as we define what does not work as well as what does work.
Among the other features of this conference was a full day devoted to the issue of people with dual sensory hearing loss. This is the first time I’ve attended a conference in which this topic was addressed at all, much less for a full day. In our focus on hearing, it is easy to forget that many people with hearing loss can also exhibit other difficulties (e.g., visual problems, arthritis). These other conditions may, depending upon their severity, impact upon the rehabilitative process in a number of ways. For example, if someone is unable to manipulate a volume control or a telephone switch, then hearing aids that function automatically in controlling the loudness of the sounds or in accessing the telephone will be required. Or telephones with large number dials would be necessary for those who have visual impairments.
In our focus on the auditory channel (hearing aids, assistive listening devices, auditory training), it is sometimes easy to overlook the vital contribution of vision to the communicative process. For people whose major avenue of communication is vision, then such apparently obvious requirements as the lighting level in the room, distance from the person talking or the screen, and line of sight become critical elements in the communicative process. For those whose primary avenue of communication is audition, the added information provided by the visual sense can range - from helpful to critical.
We’ve known for many years that people understand speech much better when they can both hear and see a speaker. Whether or not they think they are speechreading, they are to some extent. It doesn’t matter which of the modalities is the primary one for a particular person: the contribution of the other modality will increase the total recognition score. For example, as Boothroyd demonstrated in his presentation, audition will increase speech perception even if only the fundamental frequency of a speaker’s voice (artificially extracted, of course) is heard. It is not possible to understand any words with such limited acoustic information, but when combined with speechreading the scores increase beyond those obtained with speechreading alone. The reverse is also true and has been demonstrated time and again. A person may obtain a very poor speechreading- alone speech recognition score; but when combined with audition, the total score will exceed (sometimes far exceed) that obtained with audition alone. In short, anyone engaged in the AR process must be sensitive to the presence of visual conditions, whether mild or severe, that may co-exist with the hearing loss. These can include age-related macular degeneration, glaucoma, diabetic retinopathy, cataracts, and retinitis pigmentosa.
In truth, AR involves much more than scientific studies and expositions (necessary as they are); it also requires a commitment by the professionals whose who are responsible for carrying it out. And it cannot be a token or superficial commitment; they have to truly believe in the efficacy of an AR program. Given this commitment, there are a number of things that they can and should do, even within the constraints imposed by economic reality (“time is money”). They can encourage and assist their clients in acquiring and implementing a self-administered training program; in addition to the ones described above, there are a number of others as well. In their hearing aid practice, they can include and strongly encourage their clients to participate in a short-term three- or four-session hearing aid follow-up program, one that is defined as a routine component of the overall hearing aid dispensing process. This suggestion is in accord with HLAA’s position on Group HA Orientation Programs. From a purely business perspective, such a program would be a way to build customer loyalty, increase awareness and sales of other types of hearing assistive technologies, and forestall many time-consuming individual “drop-ins.” And, frankly, given the current cost of an average set of modern binaural hearing aids, if there were an added expense, it could well be absorbed by the hearing aid dispenser.
I believe that the provision and acceptance of AR fundamentally requires that our society, all of us, understand and treat the reality of a hearing loss with understanding and respect, and not as an occasion to make bad jokes. And, unfortunately, we still have a long way to go in this regard, though I do think that conferences such as the State of the Science Conference on Aural Rehabilitation are an effective way to proceed.