20Q: Hearing Aid Levels of Technology—Supporting Research Evidence?

From the Desk of Gus Mueller

At one time or another, most of us have shopped for a product that had the options of “Good-Better-Best.” The tiering of products has been around for a long time, probably going back to the early 1900s when General Motors developed a “price ladder” to differentiate Chevrolets and Buicks from Oldsmobiles and Cadillacs, creating “a car for every purse and purpose.” Typically, the goal of this tiering is to “up-sell,” or to increase overall sales. Consider that it was just back in 2010, when Uber only had “Best”—the black-car luxury service. Today, UberPOOL and UberX dominate their business.

The Good-Better-Best approach also seems to be popular for the sale of hearing aids, more so than for other medical products. This all started, or at least became common, around the time that hearing aids became digitally programmable, and we began to see multi-channel instruments. I recall that in 1989, Siemens Hearing had two programmable products, a single-channel Infiniti and a two-channel Prisma. Then in 1990, along came the Triton . . .drumroll please . . . a three-channel product! “A hearing aid for every purse and purpose.”

The tiering of hearing aids of course is not the same as when this approach is used to sell cars or mattresses or dish washers. Ethics matter. If the “Better” hearing aid costs the patient more than the “Good” product, then there needs to be evidence that it provides more patient benefit and satisfaction than the “Good.” And same with “Better” vs. “Best.” We also need to know if this increased benefit applies to all patients, or only select groups.

What does the research evidence tell us? That is what we’ll find out in this month’s 20Q. Our guest author has been directly involved in this very research topic the past few years. Patrick Plyler, PhD has a long history with the University of Tennessee, going back to his Masters and doctoral studies in the 1990s, and has been serving on the UT faculty since 2003. He currently is Professor and Program Director, Department of Audiology & Speech Pathology. He also serves as Assistant Dean for Faculty Affairs in the College of Health Professions. Dr. Plyler has received several awards for his teaching, research and editorial contributions.

This isn’t Patrick’s first visit to the pages of 20Q. Back in 2015, he had companion papers summarizing much of his research related to an individual’s ability to tolerate background noise while listening to speech—interestingly enough, a psychophysical measure that just might relate to this month’s topic, the level of technology that is most appropriate for a given patient.

Good? Better? Best? Is there really a difference? This review article most certainly will help you make that decision.

Gus Mueller, PhD
Contributing Editor

Browse the complete collection of 20Q with Gus Mueller CEU articles at www.audiologyonline.com/20Q

20Q: Hearing Aid Levels of Technology—Supporting Research Evidence?

Learning Outcomes 

After reading this article, professionals will be able to:

• Explain what hearing aid technology levels are within a manufacturer.
• Explain what hearing aid outcome measures are and are not impacted by hearing aid technology levels.
• Explain what factors impact preference with regard to hearing aid technology levels.

Patrick N. Plyler

1. What exactly do you mean by levels of technology?

Hearing aid manufacturers release products to the market as a platform or family. Each platform/family typically has multiple models that vary in technological sophistication, even though it often is the same basic chip. The models within a platform/family are often referred to as tiers or tier levels of technology since the technological sophistication rises as you progress from a basic, entry-level model up to the premium-level model. Hearing aids at the basic technology level may have features such as directional microphones and basic noise reduction algorithms, whereas hearing aids at the premium technology level include additional complex automatic and adaptive versions, as well as other features not included in the basic-level hearing aids. Each manufacturer structures their tiers a little differently; however, it is important to note that as the technology level rises, so does the cost—usually both to the audiologist and to the patient.

2. I suspect this hearing aid tiering has been going on for quite a while?

Oh yes, it probably originated back when hearing aids started having more than one channel or when some had directional technology, and others did not. I have a hearing aid order form from around 1994 that I use in class to illustrate this point to my AuD students. Even back then, we could select between Class A linear peak clipper, a two-channel Class D instrument, and a multi-channel, multi-program, digitally programmable WDRC. The products were not referred to as tier levels of technology, but that is essentially what they were, and they were sold at different price points. 

3. If the Premier Level costs more than the Entry Level, then we also should see greater patient benefit and satisfaction with the premier?

It would stand to reason that a more advanced technology level would provide increased benefit and satisfaction to the user in daily life, thereby justifying the increased cost of the premium technology devices. Consequently, many hearing healthcare providers have adopted this assumption when selecting hearing aids for their patients. For example, patients that report significant difficulty in background noise may be candidates for premium devices whereas patients that mainly report difficulty hearing the television may be better candidates for basic devices. 

4. I’m guessing there has been research studying this?

Fortunately, several studies have been conducted in recent years on this topic. The first well-designed study was conducted by our colleagues at the University of Memphis. Robyn Cox and her team evaluated the impact of hearing aid technology level on outcomes in daily life and they published the findings in three papers (Cox et al., 2016; Johnson et al., 2016, 2017). Forty- five participants were fitted with four pairs of hearing aids and each hearing aid pair exemplified basic or premium technology levels from two different hearing aid manufacturers. The participants tried each pair of hearing aids for one month in their daily lives. The researchers counterbalanced the order that the two manufacturers and technology levels were used. Hearing aid outcome measures included speech understanding and listening effort (Johnson et al., 2016), localization (Johnson et al., 2017), and the patient’s perspective (Cox et al., 2016).

5. Interesting. Did they find any differences between the tier levels?

Speech understanding and listening effort outcome measures included laboratory testing, questionnaires, and diaries. Results indicated similar outcomes between basic and premium hearing aids with one exception: listening effort for loud speech was significantly improved when using the premium technology for one manufacturer (Johnson et al., 2016). Localization outcome measures also included laboratory testing and the Speech, Spatial, and Qualities of Hearing Scale questionnaire (Gatehouse and Noble 2004). Results indicated similar outcomes between basic and premium hearing aids with one exception: localization for high frequency filtered speech in quiet was significantly improved when using the premium technology for either manufacturer (Johnson et al., 2017). Patient perspective outcome measures included questionnaires regarding quality of life and overall preference. Results failed to indicate a significant difference on any patient perspective measurement between basic and premium hearing aids (Cox et al., 2016). Taken together, the results provided no evidence to suggest premium hearing aids produced better outcomes in daily life than basic hearing aids (Cox et al., 2016; Johnson et al., 2016, 2017). However, the authors cautioned the study needed replication with different hearing aids and different manufacturers (Cox et al., 2016).

6. That is kind of surprising. No one noticed any difference between the tier levels in the real world?

Great question. The group data suggested outcomes were comparable between the basic and premium hearing aids; however, some have argued the individual’s perspective is the gold standard for determining if one hearing aid is superior to another given the particular circumstances of each individual’s environment (O’Boyle, 1977; Fischer et al., 1999; Asadi-Lari et al., 2004). Interestingly, individual data revealed that 42 of 45 participants identified a preferred hearing aid pair. Of these preferences, 12 preferred the basic hearing aids, nine preferred the premium hearing aids, and 21 preferred basic hearing aids for one manufacturer, and premium hearing aids for the other manufacturer. Although 46% of these participants indicated their preference was based on minimal to negligible differences between the hearing aids, 54% expressed a definite preference (Cox et al., 2016). Thus, individual preference was affected by hearing aid technology level for many participants. Now, why some participants preferred basic hearing aids whereas other participants preferred premium hearing aids was unclear. The authors suggested individual preference could be attributed to specific individual characteristics that resulted in better outcomes with one of the two technology levels (Cox et al., 2016).

7. I seem to recall that there also was some research on this topic from the University of Iowa.

Yes, Yu-Hsiang Wu and colleagues evaluated the efficacy and effectiveness of directional and noise reduction technologies in premium versus basic hearing aids (Wu et al., 2019). Fifty-four participants were fitted with two pairs of hearing aids. Testing was conducted in the laboratory, and the participants tried each pair of hearing aids for five weeks in their daily lives. Both hearing aid pairs exemplified basic or premium technology levels from the same hearing aid manufacturer. Hearing aid outcome measures included speech understanding, listening effort, sound quality, localization, hearing aid satisfaction, and retrospective self-reports. Interestingly, a smartphone-based ecological momentary assessment (EMA) system was used to collect participant’s real-time experiences to gain insight into the types of listening environments hearing aid users encounter in their daily lives (Wu et al., 2019).

8. Did the outcomes with the advanced features differ between the devices studied? 

Yes and no. Results indicated premium features and premium hearing aids outperformed basic features and basic hearing aids in the laboratory setting in the speech understanding and localization domains; however, these benefits did not translate to real-world settings.

9. Why would the benefit be observed in the laboratory but not in the real world? 

That is another great question. The authors proposed several possible explanations for the discrepancy between laboratory and real-world outcomes. The benefit observed with premium hearing aids may be a) too small to be noticeable in the real world, b) offset by the negative effects of distortions and artifacts generated by the advanced features and/or, c) limited by real-world factors such as visual cues and complex, dynamic listening environments. In addition, EMA results suggested participants spent most of their time in quiet as only 10.9% of self-reports were conducted in noise. This led the authors to conclude the benefits of premium hearing aids may go unnoticed if the user is rarely in demanding listening environments (Wu et al., 2019). 

10. Sounds like we’re starting to see a familiar pattern. But maybe we’re just not asking all the right questions?

These were both excellent research projects, but two things really stood out to me. First, although Cox and colleagues (Cox et al., 2016; Johnson et al., 2016, 2017) noted comparable performance between the devices on a multitude of outcome measurements, 93% of their participants reported having a preferred device. Moreover, 54% of the participants indicated having a definite preference (Cox et al., 2016). Why would so many participants have a strong preference if the performance between the device types was negligible? Second, Wu and colleagues (Wu et al., 2019) posited advanced features in premium hearing aids would go unnoticed in the real world unless the user was actually in noisy, demanding situations. This, of course, makes perfect sense. Since the participants in that study were only in noise 10.9% of the time, would the benefits of the premium devices become more salient if participants were actually in more demanding listening environments? 

As noted earlier, Cox et al. (2016) suggested that specific individual characteristics may have led participants to prefer one of the two technology levels. This led me to ask myself, “What characteristics could we be missing?” Two characteristics specific to an individual that may have impacted performance, preference, and real-world outcomes (Cox et al., 2016; Wu et al., 2019) are the ability to accept background noise and the listening demands of the environment. For example, the ability to accept background noise has been shown to vary significantly from listener to listener. Nabelek et al. (1991) developed a measure of background noise acceptance when listening to speech called the acceptable noise level (ANL). In the seminal paper on noise acceptance, Nabelek et al. (1991) proposed the amount of noise a person is willing to accept is inherent to an individual. Moreover, research suggested successful hearing aid users accept higher levels of background noise than unsuccessful hearing aid users, regardless of their ability to understand speech in noise (Nabelek et al., 2006). Although previous research evaluated speech understanding and listening effort (Johnson et al., 2016; Wu et al., 2019), the ability to accept noise was not measured in either study.

Another specific individual characteristic could be the listening demands of their environment, as the listening demands of the environment can vary from person to person. People with more active lifestyles should experience a wider range of acoustic scenes than those with less active lifestyles. Consequently, the benefit of additional complex automatic and adaptive features in premium hearing aids may only become salient for people in demanding and/or varying listening environments. If premium hearing aids can adapt to a wider range of listening scenarios than basic hearing aids, users in more demanding environments could have better outcomes with premium hearing aids and may prefer premium hearing aids over basic hearing aids. Thus, we were curious if individual characteristics such as noise acceptance and the demands of the listening environment may have impacted performance and preference with hearing aids that vary in technology level (Plyler et al., 2021; Hausladen et al., 2022).

11. Did you design a study similar to the other ones you’ve mentioned?

Yes and no. Recently, we completed two research projects that evaluated the effect of technology level on patient outcome measures in both experienced hearing aid users (Plyler et al., 2021) and new hearing aid users (Hausladen et al., 2022). In each study, outcome measures were obtained within and beyond the laboratory setting, including noise acceptance and listening demand as measured by the hearing aids during trial periods with each technology level. So yes, we did use hearing aids at the basic and premium levels and conducted trial periods in the real world with each set of aids followed by laboratory tests of speech understanding (HINT, QuickSIN) and subjective measures such as the SSQ-12, satisfaction ratings, and preference. 

Regarding the “no” part of my response, we included the ANL test as a measure of noise acceptance, a subjective measure that had not been used in the earlier research. In addition, Unitron Flex devices were used because the same devices can be programmed to exemplify basic or premium technology levels, thereby controlling for factors such as style, appearance, comfort, retention, microphone, receiver, etc. In addition, the hearing aids included a data-logging feature called Log-It-All (LIA). LIA captured the amount of time a hearing aid user encountered seven listening environments, as identified by the hearing aid’s signal classification system. Thus, the LIA feature provided information regarding the demands of the listening environment of the user instead of relying on user self-report (Plyler et al., 2021; Hausladen et al., 2022).

12. I see. Were your results any different than your colleagues at the University of Memphis or the University of Iowa?

Again, yes and no. Our results revealed similar outcomes between technology levels on most measures; however, noise acceptance and satisfaction ratings for speech in a large group were significantly improved when using the premium technology hearing aids in both studies (Plyler et al., 2021; Hausladen et al., 2022). Interestingly, preference results for experienced and new users suggested listeners in more demanding environments preferred premium hearing aids to basic hearing aids, possibly because the improved ability to accept noise was actually noticeable in their demanding, daily lives. Taken together, our findings suggested that individual characteristics such as noise acceptance and listening demands may be useful to audiologists when comparing hearing aid technology levels for potential hearing aid users.

13. Are you suggesting I should be assessing things like noise acceptance and listening demands prior to selecting and ordering a pair of hearing aids?

Based on the research (Cox et al., 2016; Johnson et al., 2016, 2017; Wu et al., 2019; Plyler et al., 2021; Hausladen et al., 2022), it is pretty clear that basic hearing aids today are more than capable of providing proper audibility, accommodating reductions in dynamic range, and even offering noise combatting strategies. As a result, measurements commonly used in routine audiological evaluations may not shed much light on which tier level your patient would be best for your patient. Focusing on other individual characteristics that are beyond the standard audiological evaluation may be more important for this goal. 

That being said, I’d like to point out two concerns from our research. In our studies, i) all participants had relatively good noise acceptance even with basic technology and ii) the listening demand was measured by the hearing aids and was unknown prior to the trial period. Previous research from our lab suggested the effects of directionality and digital noise reduction were more salient in users with poor noise acceptance than those with good noise acceptance (Lowery and Plyler, 2013). Also, the benefit of premium hearing aids was more noticeable for users in demanding listening environments. It is possible the benefit of premium technology may be even more apparent to users who have poorer noise acceptance and who are frequently in demanding listening environments. This is actually the focus of our current research, so stay tuned.

14. In all the studies you mention, aided speech recognition seems to be a popular area to study, but in my practice, it seems like it’s things like rechargeability and connectivity that separate the different tiers. Has anyone studied that?

Perfect segue. Our colleagues from Western University recently studied the impact of premium versus entry-level technology on hearing aid outcomes and preference; however, their design incorporated concept mapping in order to hone in on non-signal-processing features that may drive user preference (Saleh et al., 2021). They measured aided behavioral outcomes such as loudness ratings, speech recognition (sentences and syllables), and speech quality. Preference between hearing aids was also assessed with a 7-point Likert scale, while group concept mapping was used to investigate preference results. Participants provided comments regarding factors that influenced their preferences, which were sorted into themes that were then rated for degree of importance on a 1-5 scale.

15. What did they find?

As you might have predicted, the results were consistent with the other studies mentioned. In the laboratory, results were comparable between premium and basic technology for sentence recognition in noise, consonant recognition in noise, loudness ratings, and speech quality. The important trend across these studies is that many manufacturers appear to use similar signal processing strategies in their basic and premium tier levels. This probably explains why each research group has found comparable performance on traditional outcome measures obtained in the lab. Sticking with the theme of specific individual characteristics, these researchers found that what seems to separate the technology levels tends to be features valued by the user, such as rechargeability, streaming, smartphone adjustments, and other user-comfort applications.

16. You mentioned something called concept mapping. Can you briefly explain what it is and what did their concept mapping results reveal?

I’ll try, as this ‘concept’ was new to me as well. Basically, concept mapping is a method used to integrate ideas from participants onto an interpretable picture or map. In this study, participants provided reasons for their preferences for one type of hearing aid over the other in individual brainstorming sessions. Interestingly, the findings revealed a total of nine distinct clusters: sound quality and intelligibility, comfort and appearance, ease of use, user control, complex factors, streaming, convenience and connectivity, acoustic feedback, and multi-environment functionality. 

17. I’m a little confused. How did these clusters relate to the device the participant preferred in the real world? 

Recall earlier, I noted I was surprised in the Memphis study that so many participants had preferences despite comparable performance on the outcome measures. Our colleagues from Western University also found similar outcomes in the lab between the devices, yet following the field trial with both devices, only 17% of the participants preferred the basic technology. Not only did the majority favor the premium hearing aids, but 52% had a rating of “strong preference” (on a 7-point scale). So again, why would so many participants have a strong preference if the performance between the device types was negligible?

These researchers used the concept mapping procedure to address these seemingly conflicting findings. The highest-rated clusters for both groups were sound quality and intelligibility, comfort and appearance, and ease of use. For the importance ratings, the clusters that differed significantly between groups (i.e., rated considerably higher for the “prefer premium” group) were having access to smartphone application-based user-controlled settings, the ability to stream calls and music, and convenience features such as accessory compatibility (Saleh et al., 2021).

18. It seems like as hearing aids advance, there will no longer be features available to create different tiers? Every product will have everything?

I use this analogy with my students as I peer into the hearing aid technology crystal ball. I think hearing aids will be like the receiver you get from the cable/satellite provider. I realize most students use streaming for TV, but the analogy works just the same. The receiver is capable of allowing you access to every channel possible; however, you select the package that works best for your viewing interests and budget. At some point down the road, if you choose to add a sports package and a movie package because you are locked in the house all day due to a pandemic, you can just upgrade your package, but you don’t need to get a new receiver to do so. Your accessibility (and bill) are just modified, and you are all set. In essence, the hearing aid you select will be capable of being programmed as any hearing aid in the fleet, with the flexibility of being changed at any time. 

19. Interesting. Given all the buzz concerning OTC hearing aids over the past few months, I have to ask one OTC question. How do you think this new hearing aid category will affect the time-honored tier structure?

First, regarding OTC hearing aids, as a Professor in an Audiology program, I am concerned with educating those outside of our profession about the pros and cons of these products. We all learned early on in our training that our patients need to be counseled after a hearing aid fitting regarding realistic expectations. I am concerned OTC users will not understand the limitations of any hearing aid, much less an OTC. Also, many potential users will seek the advice of health care providers such as their primary care physician, a nurse, or their pharmacist. These professionals need some basic training on this topic, and they truly need to understand that obtaining OTC hearing aids for hearing loss is nothing like buying reading glasses for a vision problem. 

Now, to more specifically answer your question, I am not sure. I suspect we may see an expansion of the ‘floor’ as there is quite a bit of variability in the technological sophistication of OTC hearing aids. In fact, some of the higher-end OTC devices appear to be very comparable to many of what we now consider to be basic entry-level devices. I am curious if manufacturers will introduce even lower-tier “prescription” (the FDAs term, not mine) products that are more affordable that may serve as alternatives to OTC hearing aids.

20. Thanks for the conversation today. What would you say is your take-home point?

We need to be mindful when interpreting group data from these studies. We need to remember that we do not fit ‘groups.’ We fit individuals. Group data routinely show similar performance on traditional measures, leading us to conclude one product type is just as good as the other for everyone. Despite the similarities in group data, individual preference tells a different story. As perfectly laid out in the initial study by Robyn Cox, factors that are specific to an individual contribute to which device is preferred in the real world. Taken together, the findings across these studies suggest factors such as listening demand, noise acceptance, and connectivity all may impact preference.

Future studies should build on the findings reported here. Audiologists need a proven method to match the hearing aid technology level and subsequent costs to the needs and expectations of the user. This will maximize the self-perceived value of the hearing aids. Improving the self-perceived value of hearing aids will lead to increased hearing aid use in the population. Increased hearing aid use will result in improved communication ability, and improved quality of life for the millions in the population that need but do not pursue hearing aids. For the most part, this can be achieved with today’s entry or mid-level products. The premium models, however, provide many other features that a large percentage of hearing aid users rate as important. 

References

Asadi-Lari, M., Tamburini, M., & Gray, D. (2004). Patient’s needs, satisfaction, and health related quality of life: Towards a comprehensive model. Health Qual Life Outcomes, 2(32).

Cox R. M., Johnson, J. A., & Xu, J. (2016). Impact of hearing aid technology on outcomes in daily life I: The patients’ perspective. Ear Hear, 37, e224-e237.

Fischer, D., Stewart, A. L., Bloch, D. A., Lorig, K., Laurent, D., & Homman, H. (1999). Capturing the patient’s view of change as a clinical outcome measure. JAMA, 282, 1157-1162.

Gatehouse, S., & Noble, W. (2004). The speech, spatial and qualities of hearing scale (SSQ). International Journal of Audiology, 43(2), 85–99.

Hausladen, J., Plyler, P. N., Clausen, B., Fincher, A., Norris, S., & Russell, T. (2022). Effect of hearing aid technology level on new hearing aid users. Journal of the American Academy of Audiology, 33(3), 149-157.

Johnson, J. A., Xu, J., & Cox, R. M. (2016). Impact of hearing aid technology on outcomes in daily life II: Speech understanding and listening effort. Ear Hear, 37, 529-540.

Johnson, J. A., Xu, J., & Cox, R. M. (2017). Impact of hearing aid technology on outcomes in daily life II: Localization. Ear Hear, 38(6), 746-759.

Lowery, K. J., & Plyler, P. N. (2013). The effects of noise reduction technologies on the acceptance of background noise. Journal of the American Academy of Audiology, 24(8), 649-659.

Nabelek, A. K., Tucker, F. M., & Letowski, T. R. (1991). Toleration of background noises: relationship with patterns of hearing aid use by elderly persons. Journal of Speech and Hearing Research, 34(3), 679-685.

Nabelek, A. K., Freyaldenhoven, M. C., Tampas, J. W., Burchfield, S. B., & Muenchen, R. A. (2006). Acceptable noise level as a predictor of hearing aid use. Journal of the American Academy of Audiology, 17, 635-649.

O’Boyle, C. A. (1997). Measuring the quality of life. Philosophical Transactions of the Royal Society of London, Series B, Biological Sciences, 352(1363), 1871–1879.

Plyler, P. N., Hausladen, J., Capps, M., & Cox, M. A. (2021). Effect of hearing aid technology level and individual characteristics on listener outcome measures. Journal of Speech, Language, and Hearing Research, 64(8), 3317-3329.

Saleh, H. K., Folkeard, P., Van Eeckhoutte, M., & Scollie, S. (2021). Premium versus entry-level hearing aids: using group concept mapping to investigate the drivers of preference. International Journal of Audiology, 1-15.

Wu, Y. H., Stangl, E., Chipara, O., Hasan, S. S., DeVries, S., & Oleson, J. (2019). Efficacy and effectiveness of advanced hearing aid directional and noise reduction technologies for older adults with mild to moderate hearing loss. Ear Hear, 40, 805-822.