Research Presenting the 2022 Emerging Research Grantees.

Presenting the 2022 Emerging Research Grantees

Through the Emerging Research Grants (ERG) program, Hearing Health Foundation (HHF) provides seed money to scientists working across the entire spectrum of hearing and balance research, including many underfunded areas. Since 1958, ERG grants have played a foundational role in the careers of many academic researchers and clinicians in hearing and balance fields.

The competitive ERG program awards grants to only the most promising investigators. Recipients are exceptionally well-positioned to win future grants from the National Institutes of Health and other federal research funders, leading to dramatic innovations in the field.

Timothy Balmer, Ph.D.

Arizona State University

Project: The role of unipolar brush cells in vestibular circuit processing and in balance

Description: The cerebellum receives vestibular sensory signals and is crucial for balance, posture, and gait. Disruption of the vestibular signals that are processed by the vestibular cerebellum, as in the case of Ménière’s disease, leads to profound disability. Our lack of understanding of the circuitry and physiology of this part of the vestibular system makes developing treatments for vestibular disorders extremely difficult. This project focuses on a cell type in the vestibular cerebellum called the unipolar brush cell (UBC). UBCs process vestibular sensory signals and amplify them to downstream targets. However, the identity of these targets and how they process UBC input is not understood. In addition, the role of UBCs in vestibular function must be clarified. Experiments will identify the targets of UBCs, their synaptic responses, and the role of UBCs in balance. A better understanding of vestibular cerebellar circuitry and function will help us identify causes of vestibular disorders and suggest possible treatments for them. Long-term goal: To develop a better understanding of the neural circuits that underlie vestibular function. A more complete understanding of the circuitry and physiology of the vestibular cerebellum is necessary to develop therapies for vestibular dysfunction caused by peripheral disorders such as Ménière’s disease.

Balmer earned his doctorate in neuroscience from Georgia State University. He is an assistant professor in the School of Life Sciences at Arizona State University. His work investigates how neurons transmit signals to one another through synapses and how networks of neurons process information. His team uses in vitro and in vivo electrophysiology, optogenetics, immunohistochemistry, and computational modeling to understand fundamental mechanisms of sensory processing. Balmer was also a 2017 ERG grantee.

James W. Dias, Ph.D.

The Medical University of South Carolina

Project: Neural determinants of age-related change in auditory-visual speech processing

Description: Older adults typically have more difficulty than younger adults identifying the speech they hear, especially in noisy listening environments. However, some older adults demonstrate a preserved ability to identify speech that is both heard and seen. This preserved audiovisual speech perception by older adults is not explained by an improved ability to speechread (lipread), as speechreading also typically declines with age. Instead, older adults can exhibit an improved ability to integrate information available from across auditory and visual sources. This behavioral evidence is consistent with findings suggesting that the neural processing of audiovisual speech can improve with age. Despite the accumulating and intriguing evidence, the underlying changes in brain structure and function that support the preservation of audiovisual speech perception in older adults remain a critical knowledge gap. This project uses an innovative neural systems approach to determine how age-related changes in cortical structure and function, both within and between regions of the brain, can preserve audiovisual speech perception in older adults. Long-term goal: To identify the unique contributions of sensory processing, attention, and memory to better understand how multisensory integration changes with age. If we can find the cortical structures and connections between structures that facilitate a multisensory mechanism that can compensate for hearing (and vision) loss, then this mechanism can be exploited to improve the communicative abilities of older adults.

Dias received his doctorate in psychology from the University of California, Riverside. He completed postdoctoral training in the department of otolaryngology–head and neck surgery at the Medical University of South Carolina, where he is now an assistant professor. His research concerns the multisensory processing of speech and how cross-sensory recruitment may compensate for unisensory deficiencies. Dias’s 2022 ERG grant is generously funded by the Meringoff Family Foundation.

Thank You to Our Grants Reviewers

As always, HHF extends its profound thanks to our peer reviewers, a revolving group of research scientists and clinicians who donate their time and expertise to provide comprehensive review of each and every ERG proposal HHF receives. Without these reviewers’ dedication to advancing hearing and balance science, supporting newer investigators’ careers, and sustaining HHF’s Support our research: hhf.org/donate.mission, HHF could not direct our donors’ support to the innovative and promising research HHF has had the privilege of funding since 1958.

Subong Kim, Ph.D.

Purdue University

Project: Influence of individual pathophysiology and cognitive profiles on noise tolerance and noise reduction outcomes

Description: Listening to speech in noisy environments can be significantly challenging for people with hearing loss, even with help from hearing aids. Current digital hearing aids are commonly equipped with noise-reduction algorithms; however, noise-reduction processing introduces inevitable distortions of speech cues while attenuating noise. It is known that hearing-impaired listeners with similar audiograms react very differently to background noise and noise-reduction processing in hearing aids, but the biological mechanisms contributing to that variability are particularly understudied.

This project is focused on combining an array of physiological and psychophysical measures to obtain comprehensive hearing and cognitive profiles for listeners. We hope this approach will allow us to explain individual noise tolerance and sensitivity to speechcue distortions induced by noise-reduction processing in hearing aids. With these distinct biological profiles, we will have a deeper understanding of individual differences in listeners and how those profiles affect communication outcomes across patients who are clinically classified with the same hearing status. This study’s results will assist in the development of objective diagnostics for hearing interventions tailored to individual needs.

Long-term goal: To advance our understanding of the biological mechanisms of the impaired auditory and cognitive systems with the intent of improving customizable hearing interventions based on listeners’ individual differences.

Kim received his doctorate at the University of Iowa, where he studied the neural correlates of variability in speech-in-noise perception using high-density electroencephalography (EEG) under the guidance of Inyong Choi, Ph.D. Kim is currently a postdoctoral research fellow at Purdue University in the laboratory of Hari Bharadwaj, Ph.D. (Both Choi and Bharadwaj are ERG alumni.)

Manoj Kumar, Ph.D.

University of Pittsburgh

Project: Signaling mechanisms of auditory cortex plasticity after noise-induced hearing loss

Description: Exposure to loud noises is the most common cause of hearing loss, which can also lead to hyperacusis and tinnitus. Despite the high prevalence and adverse consequences of noise-induced hearing loss (NIHL), treatment options are limited to cognitive behavioral therapy and hearing prosthetics. Therefore, to aid in the development of pharmacotherapeutic or rehabilitative treatment options for impaired hearing after NIHL, it is imperative to identify the precise signaling mechanisms underlying the auditory cortex plasticity after NIHL. It is well established that reduced GABAergic signaling contributes to the plasticity of the auditory cortex after the onset of NIHL. However, the role and the timing of plasticity of the different subtypes of GABAergic inhibitory neurons remain unknown. Here, we will employ in vivo two-photon Ca2+ imaging and track the different subtypes of GABAergic inhibitory neurons after NIHL at single-cell resolution in awake mice. Determining the inhibitory circuit mechanisms underlying the plasticity of auditory cortex after NIHL will reveal novel therapeutic targets for treating

Matthew Masapollo, Ph.D.

University of Florida

Project: Contributions of auditory and somatosensory feedback to speech motor control in congenitally deaf 9- to-10-year-olds and adults

Description: Cochlear implants have led to stunning advances in prospects for children with congenital hearing loss to acquire spoken language in a typical manner, but problems persist. In particular, children with CIs show much larger deficits in acquiring sensitivity to the individual speech sounds of language (phonological structure) than in acquiring vocabulary and syntax. This project will test the hypothesis that the acquisition of detailed phonological representations would be facilitated by a stronger emphasis on the speech motor control associated with producing those representations. This approach is novel because most interventions for children with CIs focus strongly on listening to spoken language, which may be overlooking the importance of practice in producing language, an idea we will examine. To achieve that objective, we will observe speech motor control directly in speakers with congenital hearing loss and CIs, with and without sensory feedback.

Long-term goal: To fully explicate the roles of auditory and somatosensory feedback in the development and maintenance of speech motor control in typical-hearing individuals and individuals with congenital hearing loss who received cochlear implant devices. The findings will allow communication scientists and clinicians to develop novel, mechanistically driven techniques to optimize speech motor instruction to deaf children.

Masapollo received his doctorate in communication sciences and disorders from McGill University and completed two postdoctoral fellowships, one in cognitive, linguistic, and psychological sciences at Brown University, and one in speech and hearing science at Boston University. He is the director and principal investigator of the University of Florida’s Laboratory for the Study of Cognition, Action, and Perception of Speech (CAPS), which was established in 2020.

and rehabilitating impaired hearing after NIHL. Also, because auditory cortex plasticity is associated with hyperexcitability-related disorders such as tinnitus and hyperacusis, a detailed mechanistic understanding of auditory cortex plasticity will highlight a pathway toward the development of novel treatments for these disorders.

Long-term goal: To identify the molecular and cellular therapeutic targets for treating and rehabilitating the impaired hearing associated with tinnitus and hyperacusis. Kumar received his doctorate in neuroscience and pharmacology from West Virginia University and completed his postdoctoral research in the department of otolaryngology at the University of Pittsburgh, where he is currently a research assistant professor. Kumar’s 2022 ERG grant is generously funded by the General Grand Chapter Royal Arch Masons International.

Robert Raphael, Ph.D.

Rice University

Project: Understanding the biophysics and protein biomarkers of Ménière’s disease via optical coherence tomography imaging

Description: Our sense of hearing and balance depends on maintaining proper fluid balance in a specialized fluid in the inner ear called the endolymph. Ménière’s disease is an inner ear disorder associated with increased fluid pressure in the endolymph that involves dizziness, hearing loss, and tinnitus. Ménière’s disease is difficult to diagnose and treat clinically, which is a source of frustration for both physicians and patients. Part of the barrier to diagnosing and treating Ménière’s disease is the lack of imaging tools to study the inner ear and a poor understanding of the underlying causes. The goal of this research is to develop an approach to noninvasively image the inner ear and study the internal structures in the vestibular system in typical and disease states. We will utilize optical coherence tomography (OCT), a technique capable of imaging through bone, and observe changes in the fluid compartments in the inner ear. The expected outcome of this research will be the establishment of a powerful noninvasive imaging platform of the inner ear that will enable us to test hypotheses, in living animals, on how ion transport regulates the endolymph, how disorders of ion transport cause disruption of endolymphatic fluid, and how the expression of different biomarkers leads to disorders of ion transport. Long-term goal: To establish a new noninvasive method to image the inner ear that can lead to a full biophysical understanding of the molecular mechanisms underlying Ménière’s disease and related inner ear disorders that cause hearing loss, and to inspire new clinical interventions for diagnoses and treatments of inner ear diseases.

Raphael received his doctorate in biophysics from the University of Rochester. He did postdoctoral training in the department of biomedical engineering and the Center for Hearing and Balance at Johns Hopkins University. He is currently an associate professor in the department of bioengineering at Rice University where he directs the Membrane and Auditory Bioengineering Laboratory. The lab studies the biophysics of auditory and vestibular hair cells and develops models of ion transport and synaptic transmission in the inner ear. Raphael was also a 2007 ERG grantee.

Megan Beers Wood, Ph.D.

Johns Hopkins University School of Medicine

Project: Type II auditory nerve fibers as instigators of the cochlear immune response after acoustic trauma

Description: A subset of patients with hyperacusis experience pain in the presence of typically tolerated sound. Little is known about the origin of this pain. One hypothesis is that the type II auditory nerve fibers (type II neurons) of the inner ear may act as pain receptors after exposure to damaging levels of noise (acoustic damage). Our lab has shown that type II neurons share key characteristics with pain neurons: They respond to tissue damage; they are hyperactive after acoustic damage; and they express genes similar to pain neurons, such as the gene for CGRP-alpha. However, type II neurons are not the only cell type that respond to acoustic damage. The immune system responds quickly after damaging noise exposure. In other systems of the body such as the skin, CGRP-alpha can affect immune cell function. This project looks at the expression of CGRP-alpha in type II neurons after noise exposure. CGRP-alpha will be blocked during noise exposure to see if this affects the immune response to tissue damage. Long-term goal: To understand the role of CGRP-alpha in the neurons and immune response of the inner ear, which may illustrate a role for type II neurons in pain and inflammation following tissue damage. CGRP-alpha has been a target for therapeutics for painful conditions such as migraine, making it an attractive therapeutic target for pathologies of the inner ear.

Wood received her doctorate in immunology and molecular pathogenesis at Emory University. She is now a postdoctoral research fellow at Johns Hopkins University in the department of otolaryngology. Wood’s 2022 ERG grant is generously funded by Hyperacusis Research.

Please note this 2022 ERG grantee cohort follows directly from the 2020 grantees. The grant year start and end dates changed, as has the way HHF designates grant years. HHF has not skipped a year and there has been no interruption in funding.

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