Portal de Periódicos da CAPES

The Best of 2002

2003; Lippincott Williams & Wilkins; Volume: 56; Issue: 5 Linguagem: Inglês

10.1097/01.hj.0000293890.80142.14

2333-6218

H. Gustav Mueller,

Hearing, Cochlea, Tinnitus, Genetics

FigureOur Journal Club is back for another year. We've been doing this now for 8 years, and I hope that your journal club is as much fun as ours. As always, my task was to tackle the articles from the past year related to hearing aids. My review included 15 different journals and nearly 100 articles, about half of them from refereed publications. The year 2002 started off on a sad note, as we bid farewell to three old friends: Scandinavian Audiology, British Journal of Audiology, and Audiology. But, we were happy to welcome a new publication, the International Journal of Audiology, a result of the merger of those three now-defunct journals. In case you're wondering, IJA is the official journal of the International Society of Audiology, the British Society of Audiology, and the Nordic Audiological Society. The bright orange cover makes it easy to find on your desk, and several of the articles I'll be discussing were published in this new reference source. Before making my selections in individual categories, I'd like to mention a set of articles from last year that really doesn't fit conveniently into any category. A couple years back, I talked about the findings published in Journal of the American Medical Association from the comprehensive hearing aid study by the VA and the National Institute on Deafness and other Communicative Disorders. This 2000 research report sent a clear message to 350,000 JAMA subscribers that hearing aids work! Although the data are getting a little dusty, if you're interested in this research, check out the six companion articles in the August 2002 issue of Ear and Hearing (Vol. 23, No. 4). Senior authors of the articles are Vern Larson, William Henderson, Janet Shanks, Doug Noffsinger, George Haskell, and Gene Bratt. GREAT FOR THE CLINICIAN Almost all research is eventually great for the clinician, but for now let's focus on a few articles from last year that contain pearls that could be applied on Monday morning. Outcome measures tend to fall in the “rehabilitative audiology” category, but my Journal Club colleague Nancy Murray let me have this next article. Just when you were probably saying we didn't need another outcome measure, along came one—the International Outcome Inventory for Hearing Aids, or IOI-HA—you might want to try saying that a few times alone at home before using it in public. In a short summary article in the inaugural issue of IJA, Robyn Cox, Dafydd Stephens, and Sophia Kramer discuss the purpose of this new scale, and how it might be used in future research. What makes this scale unique is that it is available in 21 languages! It's also clinician-friendly, as it measures several attributes using only seven questions. Assuming that the psychometric properties of the different translations are fairly similar to the English version, IOI-HA provides a way for you to obtain reliable hearing aid benefit and satisfaction information from patients who are not fluent in English. In a separate article in the same IJA issue, Robyn Cox and Genevieve Alexander report the psychometric properties of the English version. All translations are available in print, but you might find it easier to download the information and translations you need from Robyn Cox's web site, www.ausp.memphis.edu/harl. Norms for the English version will be published soon. Another Great for the Clinician article was published by Susan Scollie and Richard Seewald in Ear and Hearing and titled “Evaluation of electroacoustic test signals I: Comparison with amplified speech.” There has been some confusion among clinicians regarding which test signals are suitable for the electroacoustic evaluation of modern hearing aids. We've heard everything from “almost any signal works” to “no signal works.” This research provides some clarification. The authors tested 41 different hearing aids, 17 of them digital, and many of the digital models had temporal modulation detectors (e.g., digital noise reduction). The hearing aids were tested using four different input signals: real speech, pure tones, Fonix composite noise, and the Audioscan swept test signal. Among their conclusions, the authors state that pure tones should not be used to estimate the levels of aided speech (they overestimate the output). They also point out that for all test signals, the match between the output for aided speech and the aided test signal becomes poorer when measurements are taken at high input levels. There's more to it than that, but it's all best understood by looking at the 37 charts provided for your viewing pleasure. My favorite article in this category comes from Todd Ricketts and Paula Henry, published in the American Journal of Audiology (AJA), titled “Low-frequency gain compensation in directional hearing aids.” As you clinicians know, directional-microphone technology causes a roll-off of low-frequency gain. Sometimes this is a good thing. Other times it's not, and we have to build back in the low-frequency gain, creating an “equalized” response. The question is, when is it necessary to equalize? Ricketts and Henry examine this for three groups of subjects with differing degrees of low-frequency hearing loss. There are several factors to consider, such as understanding speech in quiet and in noise, sound quality, and microphone noise. The authors discuss all these things in detail, but you're probably more interested in the bottom line. Ricketts and Henry say: If the low- frequency thresholds are greater than 40 dB, equalize. BEST QUICK READ If you're like me, it's tough to go an entire year without reading at least one “RECD article.” But, I do tend to favor the shorter ones. One that I liked was written by Marlene Bagatto and colleagues and appeared in JAAA. The authors report on RECD measurements obtained from 392 infants and children. That's right, 392 crying, spitting, squirming little people. This alone should earn the authors a medal! Their purpose was to examine and compare RECDs obtained using foam/immittance tips and earmolds. Average values for the two measurement methods are presented for different age groups. However, because of the expected between-subject variability within different age groups, the authors hasten to point out that the derived average values do not replace individual RECD measurements, but can be used when individual RECD measurements are not possible. Letters to the editor are usually a fun quick read, and the two I've picked are no exception. As you know, cochlear “dead regions” have been a hot topic lately. Based on their letters in Journal of the Acoustical Society of America (JASA), it appears that Christine Rankovic and Brian Moore are not quite in agreement on the topic. Rankovic, commenting on a previous JASA article from Moore's lab, suggests that the AI is generally accurate in predicting the consonant-recognition scores, irrespective of the presence or absence of dead regions. She says, “The results of the AI analysis are sufficiently accurate to call into question whether a clinical test for dead regions would offer additional predictive information.” As you might guess, Moore, who developed the TEN test for dead regions, disagrees. In his two-page response, he states: “Application of the AI to people with high-frequency dead regions might lead the clinician to spend time and effort trying to achieve the large required gain at high frequencies, only to find that this effort was fruitless… A test for dead regions, such as the TEN test, can be clinically useful, especially for people with hearing losses at high frequencies between about 60 and 90 dB, when the hearing loss exceeds 60 dB at a frequency below 2 kHz.” Regardless of your viewpoint, it's good reading. I think we need more letters to the editor. NOT READY FOR MEDLINE Unlike my Journal Club colleague Linda Hood, who often has trouble finding hearing science articles in audiology trade journals, I unearthed over 50 articles in these publications in 2002. What fuels the close relationship between trade journals and hearing aid research (aside from the obvious promotional issue) is that these publications are the best way to get research results into print before the product studied is obsolete. If you use prescriptive fitting approaches and the NAL-NL1 is one of your favorites, then you'll want to check out the following two articles. In a Hearing Journal Page Ten article, Teresa Ching reviews the NAL-NL1 procedure and discusses why she believes this method is appropriate for the pediatric population. While the DSL4.1a is often considered the “preferred” method for children (at least, in North America), you'll enjoy reading why Teresa thinks the NAL procedure deserves equal billing. In a related article in Hearing Review, Teresa Ching, Louise Britton, Harvey Dillon, and Katrina Agung provide more specific details on how to use the NAL-NL1 with children. In particular, they explain how RECDs can be used with the desired REAG (historically, the NAL procedure has used REIG targets). All good information to have if you're considering using this procedure with younger folks. It's always helpful to listen to what our patients are saying about hearing aids (and us). The person who consistently provides us with the most comprehensive information on this topic isSergei Kochkin. Last year, he published several articles based on the results of the MarkeTrak VI findings, with some of the most enlightening results showing up in the October, November and December issues of Hearing Review. You really need to read these for yourself, but here are some findings that I found particularly interesting: Despite all we know about LDL measurements, selecting maximum output, programming WDRC, and AGCo, 58% of hearing aid users say that making loud sounds less painful would be a “highly desirable” improvement in hearing aids. Giving the patient a formal post-fitting survey (regardless of the outcome) adds 10%-15% to the number of patients satisfied with hearing aids (yet only about 20% of patients receive such a survey). Increasing counseling time from 15 to 30 minutes adds 10% to the number of patients satisfied with hearing aids. Yet, many patients receive no more than 15 minutes of counseling. Another good Not Ready for MedLine article comes from Audiology Online. Written by Sarah McKay, it's titled “To aid or not to aid: Children with unilateral hearing loss.” As the name suggests, it's sometimes difficult to determine if a hearing aid will be helpful for a child with an aidable unilateral hearing loss. This article reports on post-fitting surveys from 20 children (ages 2–17) with mild-to-moderate unilateral hearing loss. Following a fitting to the “bad ear,” the children/parents responded to 12 questions related to real-world listening experiences, answered on a five-point scale (from “greatly worsened” to “greatly improved”). In general, across all categories, the findings indicated that a hearing aid usually was beneficial, with the most negative findings being “no difference.” Just another reminder that children with unilateral hearing loss often do not “get along just fine” without amplification. My favorite article in this category, from the November special issue of The Hearing Journal, was written by Pat Stelmachowicz and colleagues from Boys Town. The article, related to hearing aid verification for children, asks, “Is functional gain really functional?” The answer? Usually not! The authors illustrate the advantages of using the amplified speech spectra. While the article doesn't say much that hasn't been said before, it sends a good message. Surveys reporting the common clinical procedures of pediatric audiologists suggest that the message needs to be repeated. MOST THOUGHT PROVOKING Almost every year I find an article about loudness that I like. This year, one in Journal of Speech-Language-Hearing Research by Rebecca Warner and Ruth Bentler caught my eye. They examined threshold of discomfort (TD) for normal-hearing individuals for different complex stimuli using acoustic and sound-quality variables as predictors. The environmental sounds (10 in all) consisted of such things as a baby crying, hairdryer blowing, and, of course, a toilet flushing. Maybe I should have put this article in the Great for the Clinician section, as those of you fitting hearing aids know all too well that many wearers find specific environmental sounds uncomfortable and annoying. Warner and Bentler used these stimuli to obtain TDs for each subject, and the subjects also rated the stimuli for such things as annoyance, harshness, loudness, noisiness, and tinniness. As you might guess, the different stimuli resulted in different TDs, even though rms values were equalized. If that isn't thought-provoking enough for you, try this: The people with the highest TDs found the signals to be the most annoying. You read it right. Directional-microphone technology is a popular topic these days. The common belief, based mostly on laboratory and clinical data, is that these instruments will improve our patients' understanding of speech in background noise. However, research from Walter Reed Army Medical Center suggests that we may want to think more carefully about the magnitude of this benefit. In a paper in JAAA, Mary Cord, Rauna Surr, Brian Walden, and Laurel Olsen examined the attributes of different listening situations that would prompt a patient to favor omnidirectional over directional. And, in a second study in JAAA, these authors examined the real-world benefit derived from the two different microphone settings for a variety of listening situations. You're going to have to read these articles, but, in general, these researchers found that patients had difficulty hearing the difference between the two microphone settings and, most importantly, for several situations where one might predict a directional benefit, no advantage was found. Look for more to come on this topic in 2003. ALL-ROUND FAVORITES Some of my favorites ended up in other categories, but there are still a couple articles left that I'd like to mention. A JASA article on cochlear dead regions that I enjoyed reading was written by Thomas Baer, Brian Moore, and Karolina Kluk. They conducted speech-recognition measures (VCVs presented in quiet and in noise, with the competing noise having the same long-term spectrum as the speech stimuli). The stimuli were subjected to the frequency/gain characteristics of the Cambridge prescriptive fitting method (“Camfiltering”). The material was then low-pass filtered using several different cutoff frequencies. There were 10 subjects with high-frequency hearing loss—five with dead regions and five without. The results are quite interesting. For the subjects without dead regions, scores continued to improve as the cut-off frequency of the filter was increased. For the subjects with dead regions, intelligibility scores no longer improved when the cut-off frequency was 50%-100% above the predicted edge of the dead region. These results were similar to previous findings using the same speech signals without the competing noise. My favorite article of the year, published in Ear and Hearing, is by Pat Stelmachowicz, Andrea Pittman, Brenda Hoover, and Dawna Lewis. Our hearing aid research usually is focused on adults. Yet, amplification may have its greatest impact on infants and children. This paper is a good example of how young children can be used as subjects to collect important information on speech perception and the effects of hearing aid amplification. The primary purpose of the study was to determine how well hearing-impaired children detect the presence or absence of the /s/ and /z/ morphemes when listening through their hearing aids. For the hearing-impaired group, the results were quite variable for all age ranges. Mid-frequency audibility was the most important for the male talker, but a wider frequency range appeared necessary for the /s/ perception for the female talker. These are important considerations for the design, selection, and fitting of hearing aids. SUMMARY Well, that's it for another year. We picked out a few highlights, but there are still 75 or so hearing aid articles out there that I didn't mention. Maybe some are favorite research papers. As a wise person once said, “Research is simply formalized curiosity.” So if you are still curious next year, we'll meet again.