Hearing Research Program

The mission of the Hearing Research Program is to advance our understanding of the mechanisms and effects of hearing loss, to improve diagnostic methods, intervention procedures, and prevention strategies. The collaborative work across laboratories summarized below is funded by an NIH/NIDCD P50 Clinical Research Center on age-related hearing loss and other NIH grant mechanisms, and by generous private foundation support.

Explore Our Laboratories

Dubno Laboratory
Eckert Laboratory
Harris Laboratory
Lang Laboratory
Schulte Laboratory
Vaden Laboratory

Dubno Laboratory

Research Focus

Judy R. Dubno, Ph.D. and colleagues conduct research focused in two primary areas, understanding age-related hearing loss and developing and evaluating methods to improve access to hearing health care for older adults.  Research on age-related hearing loss uses behavioral, electrophysiologic, self-report, and genetic methods in humans and has been supported, in part, by a P50 Clinical Research Center, which has been funded by NIH/NIDCD for more than 30 years and maintains a longitudinal study of hearing in adults across the lifespan and a well-characterized longitudinal database of human subjects with normal and impaired hearing.  Additional research with multidisciplinary collaborators within and outside MUSC includes: (1) psychophysical and electrophysiological studies of cochlear function and the efferent system, and behavioral studies of communication in adverse conditions; (2) basic and clinical studies of age-related olfactory dysfunction; (3) health services research to assess the effects of hearing loss on access and delivery of health care; (4) comparative effectiveness research to evaluate cost-effective, accessible, and efficient methods of identifying and treating hearing loss in older adults, including expansion of hearing screening in primary care clinics; (5) assessment of functional outcomes of cochlear implantation using validated quality-of-life instruments; (6) health economic studies of cochlear implantation; and (7) expansion of the National Hearing Test, a hearing screening tool that uses the triple-digits-in-noise paradigm.  Overall, this research program contributes to the growing need to address hearing loss as a public health problem with a long-term goal of improving clinical care, communication, and quality of life for millions of adults with hearing loss.

Publications

Collaborators

Ted R. McRackan, MUSC College of Medicine
Ted A. Meyer, MUSC College of Medicine
Rodney J. Schlosser, MUSC College of Medicine
Kit N. Simpson, MUSC College of Health Professions
Craig A. Velozo, MUSC College of Health Professions
Lisa L. Cunningham & Katherine Fernandez, NIDCD Intramural Program
Dan Fogerty, University of South Carolina
Sara Fultz, Steve Neely & Daniel Rasetshwane, Boys Town National Research Hospital
Brittany N. Hand, Ohio State University
Larry E. Humes, Indiana University
Skyler G. Jennings, University of Utah
Gerald Kidd, Virginia Best, Christine Mason & Elin Roverud, Boston University
Robert H. Margolis, Audiology, Inc.
Sherri Smith & Howard Francis, Duke University
Charles S. Watson & James D. Miller, Communication Disorders Technology

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Eckert Laboratory

Research Focus of the Laboratory

The laboratory of Mark A. Eckert, Ph.D. conducts research focused on understanding the neural basis of individual differences in communication abilities. Current neuroimaging projects are focused on age-related changes in speech recognition that may stem from changes within the central nervous system, the consequences of hearing loss on the central nervous system, and the neurobiology developmental reading disability. This research is supported by grants from the NIH/NIDCD, and NIH/NICHD.

Please see our external site for additional information:  Eckertlab.org

Publications

Collaborators

Dyslexia Data Consortium
Federico Iuricich, Clemson University School of Computing
Ted R. McRackan, MUSC College of Medicine
Paul Morgan, Nottingham University
Rodney J. Schlosser, MUSC College of Medicine
Sherri A. Smith, Duke University Department of Head and Neck Surgery and Communication Sciences
Susan Teubner-Rhodes, Auburn University Department of Psychology
Kenny I. Vaden, Jr., MUSC College of Medicine
Zijun “James” Wang, Clemson University School of Computing

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Harris Laboratory

Research Focus of the Laboratory

The primary interest of the Kelly C. Harris, Ph.D. laboratory is in understanding the structure and function of the cochlear and neural systems underlying age-related changes in auditory processing. Current projects focus on two primary tracts, characterizing cochlear and auditory nerve function (Defining Presbyacusis), and the impact of these peripheral changes on the cortex (Cortical Plasticity). 

Age-related hearing loss in humans is complex because many factors in addition to aging can produce hearing loss in older persons, such as the accumulated effects of a lifetime of exposure to noise, ototoxic drugs, or otologic disease. Thus, targeted treatments for age-related hearing loss must address the multiple sources of pathology and their complex impact on communication. Experiments employ physiologic measures of cochlear and auditory nerve function to characterize primary sites of pathology in the cochlea and auditory nerve.  The impact of these changes in cochlear function on speech recognition and auditory processing are then assessed. Results from these experiments are expected to help move clinical assessment beyond the audiogram to identify the underlying pathophysiology associated with age-related hearing loss, important in the development of targeted therapeutic treatments. 

Cortical plasticity is a fundamental property of the brain and is the primary means by which the adult brain adapts to changing environments and enables new behavior. Aging is thought to reduce neural plasticity in the cortex, restricting the aging brain’s response to change and adaptation. Neural presbycusis, or an age-related loss or inactivity of auditory nerve fibers, may compound these effects by reducing input to the higher auditory centers, including the cortex. We use neuroimaging methods, including electrophysiology, structural MRI, and magnetic resonance spectroscopy, to examine how the aging auditory cortex reacts to a gradual loss of input from the periphery in combination with wide-spread cortical changes. Ongoing studies examine how differences in neural plasticity relate to experience and hearing handicap and affect auditory processing.

Publications

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Lang Laboratory

Research Focus of the Laboratory

The laboratory of Hainan Lang, M.D., Ph.D. conducts research focused on: 

Cellular and Molecular Mechanisms of Sensorineural Hearing Loss

Genetically modified mouse models and human inner ear tissues have been used for understanding the cellular and molecular mechanisms of auditory nerve survival and degeneration in several pathological conditions, including aging, exposure to noise and ototoxic drugs, and genetic defects. We focus on the functional roles of neural crest cell associated transcription factors, RNA binding proteins, the complement system, and their related regulatory networks for enhancing remyelination, preventing or protecting the auditory nerve from degeneration, and promoting functional recovery after cochlear injury. This translational research program provides an outstanding training opportunity for (1) cutting-edge cellular and molecular procedures in hearing research such as molecular imaging of living cochlear cells, 3D cell culture assay, RT-qPCR, NanoString and RNA-seq analysis of the degenerative auditory nerve; (2) collection and examination of mouse and human temporal bone tissues; (3) contemporary histopathological and high-resolution imaging techniques to assay human and animal inner ear specimens; and (4) evaluation of auditory function using electrophysiological techniques including the measurement of auditory nerve compound action potentials, spontaneous activities of single auditory nerve fibers, and auditory brainstem responses. The study has been supported by grants from NIH/NIDCD for more than 10 years (Lang PI). 

Adult Stem/Progenitor Cell and Auditory Nerve Regeneration/Repair

Our recent research on isolation and characterization of adult neural stem/progenitor cells from the adult mouse auditory nerve is aimed at replacing damaged spiral ganglion neurons (SGNs), preventing SGN degeneration and promoting auditory functional recovery. Several lines of studies are ongoing with a focus on remyelination and de-differentiation of adult glial cells after acute auditory nerve injury resulting from noise- or ototoxic drug-exposure.  A variety of advanced methods are employed to 1) isolate and expand neural stem/progenitor cells using neurosphere culture assay and auditory nerve micro-dissection; 2) purify and characterize neural stem/progenitor cells using transgenic mouse models and fluorescence-activated cell sorting; 3) identify the molecular characteristics of neural stem/progenitor cells using next generation sequencing, gene expression profiling at the single cell level (e.g., single cell RNA-seq), complementary proteomics assays and super resolution imaging analysis; and 4) directly evaluating functional integration of the transplanted stem cells using microsurgery and well-established mouse models of auditory nerve degeneration. The study has been supported by grants from NIH/NIDCD for more than 14 years (Lang PI). 

Peripheral Auditory System Deficits and Autism-Like Behaviors  

This is an exciting and newly developed project, which addresses a novel hypothesis that abnormal macrophage related activities, resulting from gene deficiency, lead to hearing loss and these changes may be associated with communication impairment in Autism Spectrum Disorder and other neurodevelopmental disorders. For example, mutations or deletions in the MEF2C gene has recently been linked to Autism Spectrum Disorder. In collaboration with Dr. Christopher Cowan from the Department of Neuroscience and Dr. Bärbel Rohrer from the Department of Ophthalmology, our experiments revealed that Mef2c is highly expressed in cochlear macrophages in postnatal mice and that Mef2c hypofunction results in auditory nerve functional decline and hearing loss. This research is now supported by a research grant from Simmons Foundation (SFARI Pilot Award; MPI; Cowan/Lang/Rohrer).  

Publications

Collaborators

Ted A. Meyer, MUSC College of Medicine
Jeremy L. Barth, MUSC College of Medicine
Christopher Cowan, MUSC College of Medicine
Bärbel Rohrer, MUSC College of Medicine
Eric Hamlett, MUSC College of Medicine
Steven Carroll, MUSC College of Medicine

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Schulte Laboratory

 

Research Focus of the Laboratory

The laboratory of Bradley A. Schulte, Ph.D. conducts basic biomedical research aimed at defining the molecular and cellular mechanisms responsible for generating the unique ionic and electrochemical gradients in the inner ear. Biochemical and histochemical techniques are used to identify and determine the precise cellular distribution of ion transport mediators and their associated regulatory proteins. Emphasis is placed on relating changes in auditory function with alterations in the expression of key proteins promoted by disease, noise-trauma and aging. In vivo and in vitro studies are conducted using mouse and gerbil animal models. Recent work focuses on direct correlational studies of human auditory performance with structural and molecular changes in the human inner ear.

A new research focus in the laboratory is centered around identifying specific gene variants associated with age-related hearing loss (presbyacusis). This initiative takes advantage of our P50 Center’s extensive and continuously growing database containing well-documented medical and noise exposure histories and auditory function measures along with DNA samples from large numbers of human subjects. We are performing a comprehensive population-based molecular genetic study to identify the contribution of genetic variants to presbyacusis. Causal relationships between specific genetic variants and hearing loss are assessed via functional and histopathological analyses of mouse lines generated by knock-in or knock-out of specific candidate genetic variants. We also are determining the pathological and potential functional consequences of genetic variants by assessing the distribution and changes with age in the expression pattern of promising candidate gene products and their association with pathological alterations in human temporal bones. This research is supported in part by funding from the National Institute on Deafness and Other Communication Disorders. 

Publications

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Vaden Laboratory

Research Focus of the Laboratory

The laboratory of Kenneth I. Vaden, Ph.D. performs research on age-related speech recognition difficulties and how these relate to central nervous system function. Current research projects examine brain systems that facilitate speech recognition in noise, neuroimaging analysis methods, and characterizing different forms of age-related hearing loss. This research is supported with funding from the NIH/NIDCD and the Hearing Health Foundation.

Publications

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