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Hearing Journal:
doi: 10.1097/01.HJ.0000403508.95712.ae
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Retraining the brain when hearing aids aren't enough

Pallarito, Karen

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Karen Pallarito is a freelance health writer based in Westchester County, NY, and a frequent contributor to The Hearing Journal.

When older adults can't hear the phone ring or their spouses talking to them, hearing health professionals typically recommend hearing aids that can greatly enhance their auditory signal. But even with hearing aids, patients may still have trouble making out their grandkids’ mumbling or following a conversation in noisy venues. Often, hearing-impaired adults require additional assistance to improve speech comprehension and to cope in difficult listening situations. That's where auditory training comes in.

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Auditory training aims to retrain the brain and ears much like physical therapy assists hip replacement patients in regaining strength and mobility. Experts have been employing it since World War II as part of an arsenal of aural rehabilitation services that military hospitals relied on to assist hearing-impaired veterans returning from the battleground.

New software approaches have made it easier to provide auditory training. Adult hearing aid users simply pop a CD into their computer or download software from a website and go through the training at home whenever it's convenient. Data from neurologic studies on brain plasticity support this type of training, the theory being that older brains are capable of making adaptations that may improve auditory function. Yet studies show that fewer than 10 percent of practicing audiologists offer comprehensive auditory training to their patients.

The problem is partly rooted in how the hearing health profession views its mission, suggests Robert W. Sweetow, PhD, Professor of Otolaryngology at the University of California, San Francisco. “We've gotten so trapped in this concept that we're there to help the person hear. My feeling is we should be there to help people communicate, and the hearing aids alone are just not going to cut it, no matter how good they get.”

But there are other barriers, too. For one, audiologists and hearing instrument specialists don't get directly reimbursed for providing auditory training, although speech-language pathologists do, and few hearing health professionals feel adequately prepared to provide training to adults with hearing loss because there are no clinical practice guidelines to assist them. What's more, many research questions on the effectiveness of auditory training remain unanswered. And even when the software is available to patients, they often don't follow through because they lose interest or lack motivation.

Advocates of auditory training say there are enough data to show that it works, at least for some people, and should be encouraged. “I definitely think there's a place for these programs. I just think we need to be realistic about how much somebody is going to use it and how much they're actually going to benefit from it,” says Brenda Battat, Executive Director of the Hearing Loss Association of America.

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AN EVOLVING CONCEPT

Auditory training as a therapy for adults with hearing loss has progressed significantly over the years. Originally, the idea was to train the patient to take full advantage of the auditory cues still available to him. Since then, the concept has been refined to recognize that auditory training is more than just being aware of sound cues; it's also listening in adverse conditions, says Joseph J. Montano, EdD, Associate Professor of Clinical Audiology and Chief of Audiology and Speech Language Pathology at Weill Cornell Medical College-New York Presbyterian Hospital in New York City.

There are two basic types of auditory training, explains Anne D. Olson, PhD, Associate Professor of Communication Sciences and Disorders at the University of Kentucky College of Health Sciences. Analytic, or bottom-up, training emphasizes the acoustic content of an auditory stimulus, she says, or in other words, training focuses on the sounds of speech. A patient may be asked to discriminate between pairs of words, for example, such as met vs. pet or style vs. stool, by distinguishing between the consonant or vowel sounds in each pairing. Or he may be asked to focus on differentiating between the number of syllables in words such as butter vs. bumblebee.

Synthetic, or top-down, training requires the patient to draw on his knowledge of the rules of language and to use contextual clues to derive meaning, Olson says. This type of training may involve listening to phrases or sentences, for example, and answering questions or filling in a missing word from a sentence.

Figure. Robert Sweet...
Figure. Robert Sweet...
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Some programs use both techniques. One example is Speech Perception Assessment and Training System (SPATS), a product of Communications Disorders Technology, Inc., in Bloomington, IN. SPATS was developed by a team at Indiana University, and is available through clinics where audiologists have been trained to use it. The two-part program provides bottom-up training in understanding the syllables of speech and a combination of top-down and bottom-up training in perceiving sentences in noise.

Figure. Brenda Batta...
Figure. Brenda Batta...
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Some auditory training programs are auditory only while others combine audio and visual training exercises. Computer-Assisted Speech PERception testing and training at the SENTence level, or CASPERSent, developed under a grant from the National Institute on Disability Rehabilitation and Research, “has the option of lip-reading only, lip-reading and hearing, or hearing only,” explains Arthur Boothroyd, PhD, Scholar in Residence at San Diego State University and a Chief Architect of the CASPER programs.

In addition to sharpening patients’ listening skills, most programs enable the hearing health professional to gauge a person's progress using various outcomes measures.

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GAME CHANGERS

Traditionally, among the few providers that offer it, auditory training has been provided as a clinic-based service. The Health Rehabilitation Foundation in Somerville, MA, is among the minority in providing live, one-on-one training to adults with cochlear implants as well as some hearing aid users, says Executive Director Geoff Plant.

Patients and professionals benefit from auditory training, Plant says. The patient acquires experience listening in a controlled and supportive environment, and the audiologist gains insight into the client's understanding of speech, which can help in interpreting speech test results, predicting areas of concern, and providing appropriate counseling.

As a foundation volunteer, Plant can see clients for 20 training sessions, spending between 90 to 120 minutes per session. Few hearing health professionals can afford to do that, he admits, but the introduction of computer-based programs is beginning to alter that paradigm.

One of the biggest game changers in the auditory training field has been the introduction of Listening and Communication Enhancement (LACE), which by many accounts made this type of training commercially available and easy for individuals to use at home. “It really revolutionized the idea of auditory training,” says Montano, also President of the Academy of Rehabilitative Audiology. “Prior to LACE, I think a lot of us gave it lip service.”

The first version of LACE, developed by Sweetow and Jennifer Henderson Sabes, MA, a research audiologist at the University of California, San Francisco, Audiology Clinic, hit the market in 2006. Today, Neurotone, Inc., a California-based company created to develop and market the software, offers LACE through CD-ROM, DVD, and web download.

The auditory-only program provides practice in deciphering speech in noise, understanding rapid speech, and distinguishing one voice among competing talkers. It also includes memory tasks that require the user to listen to a sentence and then recall the word presented immediately before a keyword in each sentence.

Clinicians who use the program say one of the most attractive features is the program's ability to adapt to the patient's performance, adjusting the listening situation by degree of difficulty. In that way, patients do not become overly discouraged if their performance needs improvement, and those who succeed are continually challenged. On the other hand, it is probably not the best choice for people with severe hearing loss because it lacks a visual component, some experts say.

Neurotone's Bill Woods says the company is nearing 100,000 individual users who are using or who have registered to begin the program, but not all have completed the training.

Andrew Resnick, AuD, a private-practice audiologist in New York City, says patients often ask about LACE when they see brochures in his office. When he explains how it works, a lot of people like the idea, yet a fair number of patients who purchase the program end up not doing it, he says. “It's the follow-through that we need to improve on.”

Jeffrey Shannon, AuD, who practices at Hudson Valley Audiology Center, in New City, NY, recommends auditory training on a case-by-case basis. Depending on a patient's needs, he will suggest LACE or Seeing and Hearing Speech by Sensimetrics.

The Sensimetrics program allows patients to work on their understanding of words, and is “a bit more analytic,” he says, while LACE, which is sentence-based, primarily involves “top-down, cognitive processing.”

Figure. Anne Olson...
Figure. Anne Olson...
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Among the newest entrants to the computerized auditory training field is ReadMyQuips, marketed by Sense Synergy, Inc., in Bodega Bay, CA. This program, first marketed in April, challenges the user to solve crossword-like puzzles using audio and visual information. Male and female speakers on the computer screen deliver witty sayings amid background noise that grows louder as the user's skill level improves. The person must type each quip correctly to solve the puzzle. The software may be accessed directly from the user's Internet browser or as a computer download.

“One of the problems with any method of auditory training up until now is that it's boring after a while, says software co-developer Harry Levitt, PhD, CEO and Chief Scientist at Sense Synergy and Distinguished Professor Emeritus at the City University of New York. “People have to be extremely motivated so we figured, why not make it fun, and people will use the system.” (For more on ReadMyQuips, see article on page 40.)

AudioCASPER, a hearing-only program for adults with hearing loss, is being developed under a grant from the Rehabilitation Engineering Research Center on Hearing Enhancement at Gallaudet University. This iteration of CASPER builds short stories one sentence at a time, explains Boothroyd, the project leader and a Distinguished Professor Emeritus at CUNY.

The user hears a sentence, is asked to repeat it, and then sees the text. If the person misses some words, the sentence is repeated. As the story unfolds in front of them, they can focus on the words they missed. “It's deliberately built in such a way that people will improve if they start using context better,” he says.

Researchers at Washington University School of Medicine in St. Louis, meanwhile, have developed an auditory training program that incorporates learning theory principles from cognitive psychology and uses multiple talkers based on lessons from second-language learning. Nancy Tye-Murray, PhD, Research Professor in the Department of Otolaryngology there, explains, “It's called ‘I Hear What You Mean’ because the user must make decisions based on the meaning of what they heard.”

If the speaker says “tree three,” she says, the user must select the correct answer from among four sets of pictures: a tree and a three, a tree and a tree, a three and a three, or a three and a tree. Or the user might hear a sentence, and then be asked to select the sentence that most likely would follow the one he heard based on the meaning, she adds.

The program has been in use at the university for nearly two years, and Tye-Murray hopes to make it available to others within the next 12 months or so.

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WHAT THE DATA SHOW

Among the most frequently cited studies is a review of the literature on the effects of auditory training in an adult hearing-impaired population. (J Am Acad Audiol 2005;16[7]:494-504.) Of the 213 articles identified in a preliminary search, Sweetow and Catherine Palmer, PhD, of the University of Pittsburgh, identified six that met the study criteria, which showed that the benefits of auditory training were relatively small and inconsistent.

But as Sweetow points out, that analysis was conducted before the development of LACE, and is based on older studies. He says the latest evidence suggests “a more significant effect-size from auditory training than was previously thought.”

Sweetow and Henderson Sabes put participants through extensive testing during a multisite examination of LACE. Sixty-five adults received either four weeks of LACE immediately after baseline testing (the trained group) or a month later (the control group). Additional testing was conducted two, four, and eight weeks into the study. (J Am Acad Audiol 2006;17[8]:538-558.)

Significant improvements were seen in the trained group in all but one of the outcomes measures. Four weeks after the training ended, the trained group showed marked improvements in the QuickSIN speech-in-noise test compared with baseline. When tested at a 45 dB hearing loss, the trained group showed a 2.2 dB improvement. At a 70 dB loss, the trained group improved by 1.5 dB. In each case, the control group remained essentially unchanged.

Figure. Harry Levitt...
Figure. Harry Levitt...
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As part of her doctorate dissertation at the University of Kentucky, Olson examined the LACE DVD program's efficacy in new and experienced hearing aid users. Twenty-six hearing aid users were randomly assigned to one of three groups. Two of the groups—people who have worn hearing aids for more than two years and those who have used amplification for less than six months—participated in four weeks of LACE training. A third group of new hearing aid users who received training at the conclusion of the study served as controls.

Trained study subjects participated in a series of behavioral listening tests at baseline, midway through the training, and immediately after the training to assess their performance. While both trained groups gleaned some benefit, the novice group had an edge.

“The new users who got the training clearly showed a larger training effect for understanding speech in noise,” Olson observes. While the study does not clearly tease out the reason for their improved performance, she suspects that one reason could be that communication strategies offered throughout the DVD provided some advantage because new users are not as well-versed in such techniques.

Figure. Terry Chisol...
Figure. Terry Chisol...
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Every experienced user in the study said they wished they had received the training when they were first fitted with hearing aids. Experienced users, on the other hand, commented that they already knew the communication strategies.

With so many unanswered questions, Tye-Murray and colleagues are conducting an extensive battery of tests to determine whether auditory training is beneficial for adult hearing aid users, whether single- or multiple-talker versions of auditory training are more effective, and what variables determine who is most likely to benefit from the training.

In a paper recently submitted for publication, the team examined patients’ auditory training experience and how it might be improved. Ninety-three adults, including 78 hearing aid users and 15 cochlear implant users, completed twice-a-week auditory training sessions in a clinic-like facility over a six-week period. Participants were randomly assigned to use single- or multi-talker versions of the program. An audiologist explained each activity in the program during the first session and was available to answer questions and provide encouragement.

Every participant completed a questionnaire about the program at the end of the training. Forty-eight cochlear implant and hearing aid users returned for follow-up testing and to complete a questionnaire about their participation in the study. Adults said the training was worth their time (87%), that they would take the training again (81%), and that they would recommend it to a friend (85%). Written comments suggested that the participants enjoyed interacting with the audiologist.

“I don't think it's enough to just give someone an auditory training program and send them home, and say, ‘Do this on your computer,’” says Tye-Murray. “I think it's the buy-in and the encouragement from the audiologist that keeps them engaged in the process.”

Comments also suggested that participants found the exercise empowering. “That's kind of a heretofore unheralded benefit of auditory training, and that is that it gives patients a positive way to handle their hearing loss and it gives them a locus of control over their hearing problems,” Tye-Murray says.

While 88% of participants in the study believed that they had improved in at least one aspect of spoken language comprehension, only 34 % and 22%, respectively, felt they improved on understanding sentences and multiple sentences.

The April issue of the Global Journal of Health Science offers yet another review of the evidence aimed at answering the question of whether auditory training really improves speech discrimination in hearing-impaired adults. (2011;3[1]:49; http://bit.ly/ATAR.) Researchers from the University of Bristol in the United Kingdom found that auditory training seemed to help adults with presbyacusis, but noted that the studies they reviewed were methodologically weak and lacked statistically significant outcomes. “At present one cannot conclusively say that auditory training improves speech discrimination in hearing impaired adults,” they wrote.

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A FRESH PERSPECTIVE?

For more definitive answers, many aural rehabilitation experts are awaiting final results from a large multisite, randomized controlled trial sponsored by the U.S. Department of Veterans Affairs. The study aims to assess the efficacy of auditory training in addition to hearing aids to adult veterans with hearing loss.

Veterans with hearing aids were randomly assigned to one of four groups: 20 sessions of LACE computer training, 10 sessions of LACE DVD training, directed listening to recorded books, or educational counseling on topics such as hearing loss and hearing aids (the control group).

Researchers asked what mattered more: the kinds of activities involved in LACE, such as listening to speech in noise and filling in missing words, or simply being actively engaged in any listening task, such as listening to recorded books, says the study's principal investigator, Theresa Chisolm, PhD, Professor and Chair of the Department of Communication Sciences and Disorders at the University of South Florida in Tampa.

Participants were tested on various outcomes measures before the interventions and six weeks afterward. Additional follow-up will be conducted in six months, but the study is yielding mixed results based on preliminary analyses.

“Some people in LACE training benefit on some of our outcome measures, and some of the people in the standard-of-care hearing aid group benefit as well,” says Gabrielle Saunders, PhD, one of the study's co-principal investigators and Deputy Director for Education, Outreach, and Dissemination at the National Center for Rehabilitative Audiology Research in Portland, OR. Listening to books yielded very little benefit, though, she adds.

Researchers have yet to dissect individual differences within the training groups. New and experienced hearing aid users, for example, may exhibit different outcomes, but early data from the group-to-group comparisons show that the magnitude of the benefit gleaned from the training is “not terribly huge,” Saunders observes.

Because there was enough evidence that people were improving on some measures, Chisolm says it's important to figure out exactly who benefits from auditory training. Some people do fine with hearing aids alone while others need additional rehabilitative work, she says, “and we need to try to find a way to guide people to the appropriate types of treatment.”

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NEXT STEPS

For computer-based auditory training to make headway, experts say several things need to happen, most notably additional research. Boothroyd says three broad questions should be addressed: If auditory training yields improvements, in what aspects of speech perception are they manifested? Better use of context, for example, or greater confidence? What exactly is changing? Secondly, what aspects of the training program are most responsible for those changes? And finally, what aspects of the individual affect the presence of those changes, and what is the relationship between the intervention and the outcome?

Auditory training's future also hinges on hearing health professionals’ financial stake in the game, says Montano. “If we could get reimbursement for services, I think that we would see an increase in the use of rehabilitative strategies.”

Figure. Nancy Tye-Mu...
Figure. Nancy Tye-Mu...
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For its part, the ARA is seeking to mass-market the concept of aural rehabilitation, he says. Members of the academy are presenting at several national professional meetings in the hope of putting rehabilitation strategies in the hands of more hearing health professionals.

Patients also need to be informed and involved, says Sweetow. “If the consumer demanded more assistance, if they were well aware of the presence of assistive programs, then I think it would filter down to the professional.”

As things currently stand, there is no definitive answer on the outlook for auditory training's potential growth or retraction in the future.

“When we talk to patients,” says Shannon, “We say, ‘There's some research out there that this can improve your ability to understand in noise. But there's no guarantee; there are no promises here. But it's still worth trying because it's the best that we have right now.’”

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HEARING AID MAKERS UNDECIDED ON AUDITORY TRAINING

Making auditory training software available to hearing aid purchasers makes intuitive sense, at least from a marketing perspective. But few of the largest hearing aid manufacturers are invested in this aural rehabilitation strategy.

One notable exception is Siemens Hearing Instruments, Inc. The company's homegrown program, eARena, uses a disc consisting of 20 half-hour sessions of training that can be played on a computer or in a DVD player. So far, though, there hasn't been a groundswell of takers. “I don't think we're seeing the usage we'd like to see,” says Eric Branda, AuD, Senior Manager of Product Management. For now, he says, the company wants dispensers to be aware that the product exists.

Phonak offers a dedicated LACE CD as a separate marketing piece, not tied to hearing instrument sales. “We promoted it at launch and continually inform customers that we have it via regional sales training and of course on sales calls,” says Kimberly Rawn, a Senior Marketing Manager in Phonak's U.S. headquarters. Data on the number of CDs sold to date were not available.

A spokeswoman for ReSound said the company's Global Audiology team is interested in new auditory training developments. The team investigated one program developed by university-based researchers, but found it “too complex for practical clinical use.”

In recent years, other manufacturers have backed away from distributing auditory training software. Starkey, the first manufacturer to offer LACE, announced a partnership with Neurotone in 2006, agreeing to distribute the CD version with every hearing aid purchase, for which it would pay Neurotone directly, Chief Technical Officer Tim Trine, PhD, wrote in an e-mail. But that agreement is no longer in place.

“What we quickly learned was that we had flooded the market with LACE CDs, but usage was extremely low.”

In 2007, Oticon, Inc., said it would provide LACE software to hearing health professionals whose patients purchased Oticon products. Promotional cards went out with every order for more than a year, but customer use was low, wrote Donald J. Schum, PhD, Vice President of Audiology and Professional Relations.

“We cannot justify subsidizing LACE distribution until it becomes clear that there is better acceptance by the professional community.”

© 2011 Lippincott Williams & Wilkins, Inc.

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