C HAPTER T WENTY-SEVEN Listening and Communication Enhancement (LACE) Robert W. Sweetow Jennifer Henderson Sabes
This article was reprinted with the kind permission of Thieme Medical Publishers, Inc. It appears in Seminars in Hearing Volume 28 (2), 2007. Patients presenting similar audiometric profiles frequently obtain very different benefits from amplification. Various factors may account for this. One factor relates to an individual’s assimilation of acoustic, linguistic, and environmental cues. To optimize this integration, a person must call upon many skills and processes, including cognition, auditory memory, auditory closure, auditory learning, metalinguistics, usage of pragmatics, semantics, grammatical shape, localization, visual cues, repair tactics, and effective interactive communication strategies (Kiessling et al. 2003; Hickson and Worrall 2003; Pichora-Fuller 2003). Working against many hearing-impaired individuals is the fact that certain cognitive skills (such as speed of processing and auditory working memory) that are important for comprehending speech in adverse acoustic environments, tend to diminish with age (Wingfield and Tun 2001; Gordon-Salant and Fitzgibbons 1999). Van Hooren, et al. (2005) concluded that hearing aids alone cannot improve central cognitive processes. Hearing aids can provide audibility, but may not rectify impaired frequency and temporal resolution. As a result, most hearing aid users receive incoming acoustic signals that are, to some degree, different, and presumably inferior, to that which the individual
with normal hearing receives. As a result, the hearing aid user generally receives a fragmented or partially degraded signal, either because of extrinsic sources such as noise interference or limited bandwidth, or from underlying intrinsic limitations such as imperfect audibility, cochlear distortion, and impaired frequency and temporal resolution. Moreover, hearing-impaired listeners frequently develop compensatory tactics that may be maladaptive to optimal listening. At the micro-level this may be a matter of distorting categorical perception. At a macro-level it may include misguided repair strategies. There is a fundamental difference between hearing and listening. A person can have normal hearing, but may still be a poor listener. On the other hand, a hearingimpaired person may be an excellent listener. Hearing requires audibility. But to be a good listener, the listener must integrate a number of skills including attending, understanding, and remembering. Adjunctive therapies are used for many sensory and motor disorders. When a person injures an arm or leg, professionals and the patient recognize the importance of physical therapy to strengthen adjacent muscles (the physiologic adaptation) and instruction to optimize function (the behavioral modification). Therapy also is commonly recommended for patients displaying central auditory processing disorders. It is now accepted that peripheral hearing disorders lead to central auditory changes. It is likely that the mere introduction of amplification will not produce optimal re-adaptation of the auditory system and most advantageous auditory skills unless accompanied by training. Sweetow and Palmer (2005) conducted an evidenced-based analysis of research related to individual adult auditory training and found mixed results, suggesting that at least with synthetic training, improvements in communication strategies can be expected.
Corresponding author: Robert W. Sweetow, Ph.D., Department of Otolaryngology, University of California, San Francisco, 400 Parnassus Ave., A705, San Francisco, CA 94143, 415-353-2012,
[email protected]. Jennifer Henderson Sabes, M.A., Department of Otolaryngology, University of California, San Francisco, 400 Parnassus Ave., A705, San Francisco, CA 94143, 415-821-2092,
[email protected].
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Such training on a one-to-one basis can be both timeand cost-intensive. Fortunately, there are alternatives available in our high-tech world via computerized auditory training. Computerized training has been proven effective in sensory training for other visual deficits (Cuiffreda 2002), as well as for cognitive disorders such as aging-associated memory deficits and early-stage Alzheimer’s (Gunther, Schafer, Holzer and Kemmler 2003). Also, well-established rules of perceptual learning can be implemented in a computerized protocol. For example, it is essential that the patients being trained maintain a high level of interest. Visual graphics and dynamic interaction between the patient and the computer program help maintain attention. In addition, the task must be difficult enough to present a challenge, but not so hard as to create frustration. One can accomplish this by adapting the difficulty level of the training to the individual subject. This model has proven beneficial in driving neural plasticity (Linkenhoker and Knudsen 2002). Since computerized training can be performed off-site, it can proceed at a pace based on the individual patient’s progress in a comfortable environment. Moreover, progress can be measured remotely. By carefully defining the patient’s communication profile, one can further devise deficit-specific training to fit that person’s needs. In the Kricos and McCarthy (2007) paper, a number of programs are discussed (Sims, Von Feldt, Dowaliby, Hutchinson and Myers 1979; Boothroyd 1987; Dempsey, Levitt, Josephson and Porrazzo 1992). Unfortunately, none of these programs, as of yet, enjoy widespread usage (Gagné and Jennings 2000). There are a number of potential reasons for this lack of adoption by audiologists and patients. From the professionals’ perspective, they may not be convinced that there is a need for such training, or they may lack confidence in the efficacy of auditory training. Furthermore, they may have the unsubstantiated view that modern technology is sufficient to negate the need for additional auditory training. Moreover, some audiologists may believe that additional auditory training for the patient also will require additional responsibilities and valuable, and frequently unavailable, professional time, for which they will not likely be reimbursed. Even viable alternatives, such as group aural rehabilitation, tend to be underutilized by professionals (Schow, Balsara, Smedley and Whitcomb 1993). Perhaps part of the reason for this is that group therapies tend to ignore differences among individual patients. From the patients’ perspective, many believe that they have spent enough money on products and professional programming so that they
acquire the common, but unrealistic expectation that the responsibility for success should rest solely with the hearing aids and the expertise of the audiologist. This is a primary reason why expectations, which tend to be based on the product, and thus carry no responsibility for the active participation of the patient, should be replaced by goals, which have a rehabilitative foundation, and which require the active participation of the patient. In an attempt to create a cost effective, home-based, interactive computer program designed to engage the adult hearing-impaired listener in the hearing aid fitting process, provide listening strategies, build confidence, and address cognitive changes characteristic of the aging process that may interfere with effective communication, LACETM (Listening and Auditory Communication Enhancement) was created (Sweetow and HendersonSabes 2004). The term “hearing” is purposely not used in the title of this program. Since the objective in rehabilitation is to enhance a patient’s communication abilities, an essential step is to improve listening skills. To do this the person listening must incorporate hearing, listening, comprehension, and communication. These essential elements were defined and discussed elsewhere (Kiessling et al. 2003; Sweetow and Henderson Sabes 2004).
Sweetow and Henderson Sabes (2006) reported that the following criteria had to be met for a comprehensive training program that could be implemented and accepted for widespread use in adults: • It must be cost effective; • It must be practical and easily accessible, i.e., it should be able to be implemented in the privacy and comfort of a patient’s home; • It must be interactive; • It must be sufficiently difficult to maintain interest and attention while being sufficiently manageable to minimize fatigue; • It must provide reinforcement to the patient; • Training must take place near the individual’s skill threshold; • It must proceed at the patient’s optimal pace; • It must integrate listening training with repair strategies; • It must provide the patient with feedback regarding progress or lack of progress; • It must provide for measurement and feedback to the professional that is verifiable via remote access; • It should make the patient assume some degree of “responsibility” for the ultimate outcome objective.
Listening and Communication Enhancement (LACE)
The main objectives of LACETM are to enhance listening and communication skills, get the patient involved in the therapeutic process, improve confidence levels, provide communication strategies, reduce unnecessary visits, and help the patient recognize that hearing aids address hearing, but do not correct listening and communication skills.
How Does LACETM Work? LACETM is designed for use in the privacy of the patient’s home. Version 1 requires the use of a PC or Apple home computer, but future versions may allow for use of self contained, portable dedicated hardware that can be loaned or rented to the patient who does not own a computer or is not computer literate. Therapy is recommended for 30 minutes a day, 5 days a week, for four weeks. Training is conducted at the trainee’s most comfortable level (MCL) and, for aided listeners, should be done with hearing aids set to use level. LACETM provides a variety of interactive and adaptive tasks that are divided into three main categories (degraded speech, cognitive skills, and communication strategies). The exercises chosen for LACETM were chosen for accessibility, ease of use, and subject feedback from a pilot study. Training is organized into topics (health issues, money matters, exercise, etc.) that are selected by the trainee at the beginning of each training session. This reinforces the importance of using contextual cues by keeping the general topic in mind when listening. Stimuli were recorded from male, female, and child talkers, in order to present acoustic variation. A demonstration of the LACE training exercises can be downloaded at http://info.lacecentral.com/. For degraded speech exercises, (which constitute approximately 70% of the training), speech is either time compressed (TC task) to simulate rapid speech, or presented with background babble noise (SB task) or a single competing speaker (CS task). The patient listens to and identifies the signal, then views the correct response on the screen. If it was correctly comprehended, the next sentence will be a little more difficult, or if it was incorrect, the next sentence will be easier. In other words, the difficulty level of the task adapts based on the accuracy of the person’s response to the previous task. For example, for the speech in noise or competing speech exercises, if a subject can correctly identify a sentence presented at a +2 dB signal-to-noise ratio (SNR), the next presentation would be made at a 0 dB SNR. Or, if the subject cannot correctly identify the stim-
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ulus at a + 2 dB SNR, the next presentation would be at a +4 dB SNR. For rapid speech, the ratio of time compression changes in a similar adaptive manner. In this way, both boredom and frustration are minimized. There are two cognitive training exercises, missing word (MW) and target word (TW) in Version 1 of LACETM. The TW task is a cognitive training task incorporating both auditory memory and speed of processing. It constitutes approximately 15% of the training. In this task, the subject is visually presented with a target word. The subject is next prompted to listen to a sentence in quiet. The target word is one of the words in the sentence. Following the auditory presentation of the sentence, the trainee is asked to respond via a multiplechoice option by selecting the word that occurs just prior to the target word in the sentence. The sentence is then visually presented with the correct word underlined on the visual display. When the patient answers consecutive presentations correctly, the algorithm increases the difficulty of the task. The difficulty of the task varies not only based on the length of the sentence, but also by the order in which the task is presented. For example, the second difficulty level does not reveal the target word until after the sentence is presented, thus requiring the subject to retain the sentence in short term memory until completing the task. If the trainee successfully responds to two consecutive stimuli, the program becomes more difficult by presenting two target words and two sentences. The program allows for six levels of difficulty. If the trainee incorrectly answers two consecutive presentations, the task difficulty is decreased in the opposite manner. Each successive training session begins at one level of difficulty easier than the average performance of the previous session. The remaining 15% of the LACETM training involves the presentation of approximately 150 communication strategies in the form of “helpful hints”. Interactive communicative (IC) strategies include, but are not limited to, topics such as managing the acoustical environment, assertive listening skills and communication strategies, care and maintenance of hearing aids, assistive listening devices, and realistic expectations. Periodically during, and at the conclusion of each exercise, training is briefly interrupted with a differently colored screen. On this screen is a “helpful hint” conveying aural rehabilitation or interactive communication information. In the authors’ clinic, subjects also are provided with a supplemental materials booklet and are instructed that if a “helpful hint” is found to be of particular interest, more information can be reviewed in the supplemental packet at the end of the training session.
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In addition to the immediate feedback for each task, LACETM provides the patient with a graph depicting daily progress and improvement from the start of the training. Furthermore, the results of the training are tracked and electronically transmitted to a HIPAA compliant secure website accessible by the audiologist so that the progress may be monitored.
Effects of Training In a multi-site study of the effectiveness of a pilot version of LACETM on 65 subjects, Sweetow and Henderson Sabes (2006) reported significant improvements on not only the training tasks, but also on a variety of standardized outcome measures including the Quick Sin, Hearing Handicap Scale for the Elderly (HHIE), and Communication Scale for Older Adults (CSOA). Subjects ranging in age from 28–85 were randomly placed into one of two groups. Group one subjects started the training immediately after the initial testing session. Group two subjects completed the initial test session, returned one month later and completed a second test session (end of control period) and then started training (crossover period). There were no significant differences between the trained subjects in groups one and two, so the data were pooled for these two groups. The demographics of the groups have been previously published (Sweetow and Henderson Sabes, 2006). Fifty-six subjects were experienced hearing aid users (six months to 44 years). Approximately 85% wore binaural amplification, and nine subjects did not use amplification but reported difficulty understanding speech in adverse listening environments. New hearing aid users were not included in this study due to possible effects of acclimatization. Thus, the changes seen in this study were due solely to listening and communication training, rather than the introduction of amplification or a change in technology. Group one, the immediately trained group, had testing completed prior to training (baseline), two weeks into the training (mid-training), at the end of the four
week training program (post-training), and at eight weeks (four weeks post training). Group two, the crossover subjects, received testing at baseline, and four weeks later, just prior to training. They then received testing at two weeks into the training (mid-training at the end of the four-week training program (posttraining), and at eight weeks (four weeks post-training). Sixty percent of the subjects improved in all of the training tasks. Eighty-three percent of subjects improved in all but one of the training tasks. Average differences between the first week of training and the fourth week of training are as follows: 2.8 dB SNR improvement in Speech in Babble (SB), 6% compression ratio improvement in Time Compressed Speech (TC), 3.8 dB SNR improvement in Competing Speaker (CS), .65 difficulty level improvement (difficulty levels ranged from 1 to 6) in Target Word memory (TW), and a 0.5 sec improvement on the Missing Word response time (MW). Eighty-seven percent of the subjects had quarter four scores that were better than quarter one scores on the SB, 84% of the subjects had quarter four scores that were better than quarter one scores on the CS, and 88% of the subjects had quarter four scores that were better than quarter one scores on the TC tasks. Eighty percent of the subjects had quarter four scores that were better than quarter one scores on the TW and 75% of the subjects had quarter four scores that were better than quarter one scores on the MW tasks. All of these results showed statistically significant improvements (p1.6 dB SNR loss improvement) for the 45 dB and 70 dB presentations respectively. The average improvement for the trained subjects on the HINT (hearing in noise test) was 0.9 dB, however this was not significantly different from the control subject group. Only 55% of the trained subjects showed any improvement on the HINT. The average improvement for the trained group on the HHIE/A was 7.5 points, with 76% of the subjects showing improvement. The average improvement for the trained group on the CSOAA and CSOA-S was 0.06 and 0.14 points, with 63% and 68% of the subjects showing improvement, respectively. The nine subjects that did not use hearing aids also showed some improvements in performance. These subjects were younger with better hearing and test scores than the average hearing aid user. As a group, these sub-
jects showed lesser, but still significant improvements on the SB and CS training tasks. On the other on- and offtask measures, improvements were not significantly different from baseline (p
