Hearing aid processing no longer operates under the assumption that the real-world listening environments are represented by simple laboratory test conditions, such as the talker of interest is in front with noise behind, or even that there is only a single talker of interest. In addition, the driving philosophy has shifted from treating a single complaint (e.g., understanding in noise) to holistically treating individuals across the full range of their real environments and experiences (e.g., connecting to an auditory world). While improving speech recognition is still the primary goal of amplification, research is moving to include considerations from personal relationships to general health and well-being.  

In addition to advances in hearing aid technologies and how hearing loss impacts the patient as a whole, there are also ongoing advances in how we assess patient outcomes in the real world. This recent research has reinforced the breadth of potential amplification benefits which, in turn, has renewed interest in increased accessibility to hearing health care. We considered these general themes when recruiting the organizing committee and this year’s speakers. We were able to line up an exceptionally qualified group of speakers who addressed current and future directions in amplification. 

From considering hearing loss from a public health perspective to new advances in technology, service delivery, and assessing patients’ needs and outcomes, our six expert speakers for ARC 2019 brought an unmatched and forward-thinking perspective. Not surprisingly, the feedback we have received thus far has been incredibly positive. 

ARC 2019 truly had something for everyone with an interest in adult hearing aid candidates. In addition to our exceptional speakers, ARC 2019 also included a lunch-time poster session with several interesting posters from hearing aid researchers and students. An associated student poster competition provided travel support for several students to attend ARC, further enhancing the experience for all. ARC 2019 provided the most up-to-date and cutting-edge information in amplification. These exceptional thought leaders also provided insight into the future, in an area for which rapid change continues to be expected. The following abstracts summarize their presentations.

Hearing Loss in the Third Era of Public Health—From Epidemiology to Public Policy

Frank Lin, MD, PhD, Professor of Otolaryngology, Johns Hopkins University

Holding hands imageResearch over the past several years has demonstrated the broad implications of hearing loss for public health and the functioning of older adults, particularly with respect to cognitive functioning, brain aging, and dementia. This epidemiologic research has directly led to current national initiatives in the United States focused on hearing loss and public health. These initiatives include the Aging and Cognitive Health Evaluation in Elders (ACHIEVE) randomized controlled trial and recent passage of the bipartisan Over-the-Counter Hearing Aid Act in 2017. This federal law overturns over 40 years of regulatory precedent around hearing aids in the United States in order to directly improve the accessibility and affordability of hearing care for older adults. This session reviewed hearing loss and amplification from a public policy perspective and described how this view has the potential to shape not only events to date, but also the future of hearing health care.

Real-World Hearing Aid Benefits Are More Apparent in Real Time: Ecological Momentary Assessment

Yu-Hsiang Wu, PhD, Associate Professor, Department of Communication Sciences and Disorders, University of Iowa

Retrospective self-reports (e.g., standardized questionnaires completed by patients) have been widely used in audiology research, as well as clinical settings. Despite their proven value in quantifying behavioral change and rehabilitative planning, retrospective self-reports often have low context resolution and are subject to recall bias. Likely due to these disadvantages, retrospective self-reports often fail to detect the outcome difference between different hearing aid technologies in the real world. 

One technique that has been developed to overcome the disadvantages of retrospective self-reports is Ecological Momentary Assessment (EMA). EMA is a methodology involving repeated assessments/surveys to collect data describing respondents’ current or very recent (i.e., momentary) experiences and related contexts in their natural (i.e., ecological) environments. Because detailed contextual information can be collected in each assessment, EMA has high context resolution. Also, because experiences are recorded almost immediately in each assessment, EMA is considered to be less affected by recall bias. 

In the past few years, the Hearing Aid and Aging Research (HAAR) laboratory at the University of Iowa has been using EMA in hearing aid outcome research. The collected EMA data suggest that the effects of hearing aid technologies (e.g., directional microphones and noise reduction algorithms) in the real world are often context-dependent. That is, greater hearing aid benefits can be realized in certain real-world contexts, but not in all listening situations. By comparing hearing aid outcome data collected using EMA and retrospective self-reports, the data collected in the HAAR further indicate that hearing aid benefits experienced by listeners in real time are more apparent than what is conveyed in retrospective self-reports. In other words, users may experience more benefits from hearing aids than what they remember. Therefore, the benefits of hearing aid technologies in the real world could be larger than what has been reported in previous studies that asked research participants to recall and integrate their experiences across various contexts over weeks and months in retrospective self-reports.

Technology Trends Shaping the Future of Hearing Health Care

Brent Edwards, PhD, Director of the National Acoustic Laboratories, Sydney, Australia

Modern hearing aid options imageThe pace of innovation in hearing health care is faster than it has ever been, with changes to technology, services, and delivery channels that will forever impact people with hearing loss and the professionals who provide hearing health care. These advances span the hearing landscape from the medical domain across to the consumer domain, from implantable devices to OTC to self-diagnostic apps. 

This lecture provided the context for which telemedicine, machine learning, new delivery models, and other advances will shape who will be the new consumers of hearing health care, how they will receive treatment, and what that treatment may look like.

Can Hearing Aids Change the Way Adults Respond Emotionally to Sounds?

Erin Picou, AuD, PhD, Research Assistant Professor, Department of Hearing and Speech Sciences, Vanderbilt University

Emotion plays an important role in our daily lives. We respond emotionally to many daily experiences, such as listening to music or a baby crying. Although we might not always recognize these emotional responses, they do influence our attention, cognition, and feelings of well-being. Emotional responses are often described using two dimensions, valence (pleasant versus unpleasant) and arousal (exciting versus calming). Pleasant emotions include happiness, contentment, and joy, whereas unpleasant emotions include misery, depression, and sadness. Pleasant emotions motivate us to approach positive experiences and broaden attention. Unpleasant emotions prepare people to handle potentially undesirable situations and focus attention. Thus, a full range of emotions is normal and desirable, as all types of emotional responses serve a distinct purpose. 

Recent research has shown that adults with acquired, mild to moderately severe, sensorineural hearing loss demonstrate a reduced range of emotional responses to sounds (e.g., laughter, crying, music). That is, they feel less pleasant in response to pleasant sounds and less unpleasant in response to unpleasant sounds, relative to their peers with normal hearing. We have also found that disrupted emotion perception associated with hearing loss is evident in emotional responses to television viewing, a very common leisure activity for older adults. Interestingly, the effects of hearing loss on emotional responses are not related to advancing age, and instead are associated with aspects of hearing loss, specifically reduced intelligibility and reduced high frequency audibility. 

Unfortunately, current research has shown that increasing the overall level to compensate for reduced audibility can have adverse effects on emotion perception, rather than restorative effects. Hearing aids fit to prescriptive targets with no active advanced features increase overall level and also improve high frequency audibility. However, the combined effect for most listeners with hearing loss is further disrupted emotion perception. Conversely, use of non-linear frequency compression improves emotion perception relative to conventional processing, likely as a result of improved high frequency audibility without additional loudness. Emotion perception in hearing loss is an emerging field with potential to affect listeners across a range of listening experiences. However, more work is necessary to fully understand the intervention strategies that can optimize emotion perception and offset the negative effects observed to be associated with sensorineural hearing loss.

A Novel Treatment for Hyperacusis: Overcoming the Limits of Traditional Hearing Aids

David Eddins, PhD, Professor, Departments of Communication Sciences and Disorders and Chemical and Biomedical Engineering, University of South Florida, and Co-Director of the Auditory and Speech Science Laboratory

Patients who suffer a debilitating intolerance to the loudness of everyday sounds, a condition known as hyperacusis, present a unique treatment challenge. Such patients often present in the clinic engaged in a form of self-treatment involving wearing earplugs (EPs) to limit offending sound exposures. We and others have shown chronic use of EPs increases auditory gain and exacerbates the hyperacusic condition, rendering the EP wearer even more sensitive to loud sounds. Despite this common result, effective clinician-driven treatment protocols for hyperacusis do exist. 

Formby and colleagues completed an NIH-sponsored clinical trial of unaided sound therapy that demonstrated the effectiveness and efficacy of the sound generator (SG) component of sound therapy targeting hyperacusis (Formby et al, 2015; Sem Hear 36(2):77–109). The result was objective and subjective improved sound tolerance. This result is consistent with several reports published by Formby reporting the outcomes of patients engaged in sound therapy with SGs as part of tinnitus retraining therapy (TRT; Formby et al, 2007; Sem Hear 28(4):276–294). These results are consistent with research demonstrating that chronic use of ear-level SGs, even by listeners with normal hearing and normal sound tolerance, results in increasing tolerance for loud sounds. 

The dilemma then is to figure out how to wean the typical hyperacusic patient off of their maladaptive, sound-attenuating devices that provide comfort and reduce anxiety and transition them into ear-level treatment devices that include SGs to produce low-level therapy noise. This presentation described a novel transitional device incorporating both EPs and SGs and an associated fitting protocol for treating the severely hyperacusic patient. 

To meet the patient’s pre-treatment needs, a deeply seated and acoustically sealed in-the-ear mold offers maximum sound attenuation. The ear mold contains a heat-activated stent that expands at body temperature to augment the normal seal, functioning as a high-quality, custom EP. A miniature behind-the-ear hearing device is connected to the earmold through a slim tube. The device has an on-board SG to create the therapeutic low-level, spectrally-shaped noise. As the SG induces loudness tolerance change, amplification approaches unity gain over time to overcome the maladaptive plasticity associated with earplugging. Simultaneously, output limiting (loudness suppression) reduces the exposure to loud, offending sounds. If the patient has aidable hearing loss, the device can function as a fully-featured hearing aid.   

The associated fitting protocol and custom fitting software establishes real-ear unaided gain, real-ear occluded gain, real-ear aided (unity) gain, and real-ear noise response. Output limiting, based on loudness discomfort levels and imposed under conditions of unity gain, minimizes exposure to loud sounds while providing access to soft and comfortably loud sounds typically attenuated by an EP that otherwise exacerbates hyperacusis. The patient undergoes counseling on use, care, goals, and expectations that the low-level noise will enhance sound tolerance. On subsequent visits, the resulting SG-induced increases in loudness tolerance determine the release of loudness suppression and the transition of the patient from EPs to normal, device-free audition, ultimately offering an effective treatment for debilitating hyperacusis. Work Supported by NIDCD R21 DC015054.

Nothing Stays Still: Physical and Attentional Movement as Essential Components of Listening and of Future Hearing Aids

Graham Naylor, PhD, Scientific Program Leader, Faculty of Medicine and Health Sciences, The University of Nottingham, Glasgow, U.K.

Man experiencing motion imageFor decades, research into listening performance has been almost exclusively based on static situations, where neither the sound sources nor the listener move. Likewise, listening tasks have mostly been highly constrained and artificial. These limitations have been made deliberately, in order to maintain close control and exclude ‘random’ effects, so that basic mechanisms of perception could be observed and described. The result has been an impressive understanding of how auditory perception works under such conditions, which has helped to advance the development of hearing devices from basic amplifiers toward the sophisticated environment-aware systems we see today. 

Recently, a wave of research has begun that goes beyond the old paradigm and acknowledges that our sensory systems have evolved to be exquisitely sensitive to change, that the attentional networks in our brains are constantly in flux, and that the real world is full of motion and change. This unlocks a Pandora’s box of natural behavior, where a huge amount of important phenomena are to be found, with massive potential for the understanding of hearing disability and the development of future hearing devices.

When they are immobile, normal-hearing listeners are highly sensitive to the movement of sound sources. However, when the listener moves their head, in order for a sound source to be perceived as immobile, it actually has to move slightly too—with or against the direction of the head movement, depending on whether the sound source is in front or to the side. Thus, even at the level of basic perception, introducing movement fundamentally changes the shape of the auditory world.

Moving from basic psychoacoustics toward natural behavior, substantial work has been done concerning changes in speaking and listening behaviors as environmental conditions (e.g., noise, reverberation) change. These studies have shown changes in speaking rate, intensity, pitch, and pause count, and in listener head orientation, distance to source, and reliance on visual cues. However, almost all previous work has used speakers and listeners in isolation. 

Real conversation is fundamentally different, because (1) it requires speech planning while listening, (2) the contributions of participants are not independent, and (3) social norms place constraints on acceptable behavior. Lab measurements on freely conversing pairs of hearing-impaired participants have extended the previous results to include changes in turn-taking as evidence of conversational repair/breakdown in adverse levels of noise. Ongoing studies of three-way conversations indicate that movement patterns may be affected by the type of background noise, which might have implications for optimal settings in directional microphone systems.

Future hearing devices will attempt to apply knowledge of attentional and behavioral dynamics in order to optimize communication performance. As devices incorporate more and more extra sensors, such as motion detectors or in-ear electroencephalogram (EEG) electrodes, they will become capable of obtaining continuous estimates of the wearer’s behavioral or attentional state. How such data will be put to good use remains an open question for now; certainly, there are big technical and use-case challenges. Whether such systems will be beneficial will depend on good design and deep understanding of user behavior. 

The real world is messy, and we have only just started to mine natural behavior for insights that can drive future hearing-device development. However, it is clear that, by regarding dynamic aspects of environments and behavior as essential components of real-life listening, we will gradually reveal new ways in which devices can help people with hearing difficulties.

Conclusion

The theme of next year’s Academy Research Conference will be auditory neuropathy spectrum disorder (ANSD). This disorder is a unique condition that occurs in individuals with normal cochlear outer hair cell function and disordered afferent neural activity at the level of inner hair cell synapses, the auditory nerve, and/or brainstem. While the incidence rate is unknown, ANSD can affect individuals across the lifespan. Scientists do not fully understand the pathogenic mechanisms that underlie this condition, which can make diagnosis and management a difficult clinical challenge. 

With conference chair Linda Hood, PhD, next year’s event will present the latest translational research as it relates to examination of the etiology of ANSD, evaluation, and management. ARC 2020 will be held on April 1 in New Orleans, Louisiana. 

Recordings of the ARC 2019 presentations can be found here.