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Karina S. Cramer, Ph.D.

Karina S. Cramer, Ph.D., M.D.

Associate Professor at the University of Texas Medical Branch (UTMB), Department of Otolaryngology Head and Neck Surgery

Karina S. Cramer, Ph.D., M.D.

Hearing Loss Caused by Lassa Fever

Tomoko Makishima is an Associate Professor at the University of Texas Medical Branch (UTMB), Department of Otolaryngology Head and Neck Surgery, on Galveston Island, Texas. She obtained her M.D. and Ph.D. at Kyushu University in Fukuoka, Japan, studying the molecular mechanism of apoptosis. She then completed residency training in Otolaryngology in Japan before coming to the NIDCD, NIH, as a postdoc in Dr. Andrew Griffith’s lab to study genetic hearing loss in humans and in mice models. She has been at UTMB since 2005 as a clinician-scientist splitting her efforts between patient care and research. Her research focuses on the molecular mechanisms of hearing and balance disorders and uses a combination of molecular biology and auditory and vestibular behavioral analysis in humans and in mice models.

In recent years, her lab has been tackling various otolaryngologic sequelae of viral infections in collaboration with the Pathology Department and the high containment Galveston National Lab at UTMB. Currently her lab is working on characterizing hearing loss and balance dysfunction caused by Lassa virus in mice models as well as in human subjects through a collaboration with Jos University, Nigeria.

Karina S. Cramer, Ph.D.

Tejbeer Kaur, Ph.D.

Assistant Professor of Biomedical Sciences at Creighton University

Tejbeer Kaur, Ph.D.

Diversity and Function of Microphages in Normal and Damaged Ears

Dr. Tejbeer Kaur is an Indian immigrant and an Assistant Professor of Biomedical Sciences at Creighton University in Omaha Nebraska. She obtained her PhD at the Southern Illinois University, Springfield, Illinois where she studied the role of inflammation and STAT transcription factors in cisplatin (cancer drug)-induced ototoxicity and hearing loss. She completed postdoctoral training at Washington University, St. Louis, Missouri. In the Kaur Lab, the research aims to understand the complex biology and interactions of immune cells and their effector molecules with the sensory cells in the cochlea of the inner ear and how these interactions influence hearing, hearing loss and sensory cell development, degeneration, repair, survival, and plasticity. Inner ear contains a resident population of macrophages (innate-immune cells). Importantly, sensorineural hearing loss due to ototoxic side effects of certain medications, noise trauma, infections or healthy aging is associated with inflammation and robust activation and increase in numbers of macrophages. However, the precise functions of macrophages and inflammation are unclear. Dr. Kaur’s early research demonstrated a critical role of macrophages in the survival of afferent neurons in the injured cochlea and identified a novel neuron-immune signaling axis, fractalkine signaling that regulate the spontaneous repair of ribbon synapses and long-term survival of neurons in the injured cochlea. Recently, she and her colleagues have delineated a new role for cochlear macrophages in ribbon synapse repair after noise-induced synaptopathy. Her ongoing work focuses on understanding the diversity and functions of macrophages and their effector molecules in normal and pathological ears and to develop novel immunotherapies to prevent and/or restore loss of hearing and sensory cells and to maximize hearing aids and cochlear implant technologies for treating sensorineural hearing loss.

Karina S. Cramer, Ph.D.

Karina S. Cramer, Ph.D.

Professor, Department of Neurobiology and Behavior, University of California, Irvine

Karina S. Cramer, Ph.D.:

Microglial Roles in Auditory Brainstem Development

Dr. Karina S. Cramer is a Professor at the University of California, Irvine in the Department of Neurobiology and Behavior. She obtained her Ph.D. at the California Institute of Technology, where she studied neuromuscular development. She completed postdoctoral training at MIT in visual system development, then shifted to auditory system development at the University of Washington. Her laboratory at UC Irvine investigates the developmental mechanisms that assemble auditory brainstem circuitry, particularly in regions that enable sound source localization. Her early research demonstrated roles for Eph family proteins in axon targeting and formation of tonotopy in auditory system development. She and her colleagues have identified new axon guidance roles for molecules in the apoptotic pathway. Her ongoing research also explores the functions of glial cells, including astrocytes, microglia, and oligodendrocytes, in the maturation of auditory brainstem circuitry.

Dr Keithley

Dr. Elizabeth M Keithley: Immune Mechanisms of the Inner Ear

Dr. Elizabeth M Keithley (Betsy) presented her talk entitled, "Immune Mechanisms of the Inner Ear" as part of the ARO Seminar Series.   Dr. Keithley is an emeritus professor at the University of California, San Diego Department of Otolaryngology/Head and Neck Surgery.  She joined the faculty there in 1985.   She received her Ph.D. in anatomy from Boston University in 1980 where she investigated age-related changes in the inner ear.  She then completed post-doctoral training through Massachusetts Institute of Technology at the Eaton-Peabody Laboratory where she investigated the physiological activity of auditory neurons.  During her career at UCSD she studied both age-related mechanisms of cochlear degeneration as well as immune responses in the inner ear.  She trained numerous undergraduate and medical students and otology fellows.   She served the Association for Research in Otolaryngology as Chair of the Program Committee, a Council member in the 1990s and Secretary-Treasurer, 2002-2005.  She retired in 2010.  She now serves as Chair of the Board of Directors of the Hearing Health Foundation and on The Escondido Creek Conservancy.

Dr. Thomas Friedman: 'Hereditary deafness conundrum: Is a noncoding variant naughty or nicely in disequilibrium'

Dr. Thomas Friedman's talk was titled, 'Hereditary deafness conundrum: Is a noncoding variant naughty or nicely in disequilibrium'.
Since 1996, Tom Friedman has been the Chief of the Laboratory of Molecular Genetics in the Intramural Program of the National Institute on Deafness and Other Communication Disorders (NIDCD) at the National Institutes of Health (NIH), Bethesda, Maryland. For the past 26 years, the focus of his research lab at the NIDCD has been the identification of variants of genes associated with human deafness and syndromes that include deafness and mouse models to study inner ear pathophysiology. For the previous 18 years beginning in 1978, Tom was on the faculties of the Zoology Department, College of Natural Sciences and also the Department of Pediatrics and Human Development at Michigan State University (MSU). For four years, he also served as the Director of the Graduate Program in Genetics, an interdepartmental PhD granting program at MSU. Following completion of his PhD as a graduate student at the University of Michigan, Tom was a post-doctoral fellow in a biochemistry laboratory at the National Institute of Mental Health (NIMH) at the NIH where he studied galactose metabolism in cells from galactosemic patients. His dream after completing his post-doctoral experience at the NIH was to one day return to the Bethesda Campus and focus 100% of his time on human and mouse genetic research and the training of a highly diverse group of upcoming scientists and future ARO members. This session was be moderated by Dr. Inna Belyantseva.

When: Wednesday, September 28th at 12:00 PM Eastern

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Dr. Lisa Goodrich: 'Genetic Dissection of Cochlear Circuitry'

Dr. Lisa Goodrich's talk was titled 'Genetic Dissection of Cochlear Circuitry'. 


Dr. Lisa Goodrich received her undergraduate degree in Biology summa cum laude from Harvard University in 1991. After a year working as an electron microscopist at University College Dublin, she joined the PhD Program in Neuroscience at Stanford University School of Medicine. For her graduate work with Dr. Matthew Scott, she cloned Patched orthologs and demonstrated the importance of Patched signaling in the developing nervous system and its relevance to cancer in humans. She continued to study mechanisms of neural development as a postdoctoral fellow in the lab of Dr. Marc Tessier-Lavigne, where she participated in a gene trap mutagenesis screen to identify novel axon guidance receptors. Since starting her own group in the Department of Neurobiology at Harvard Medical School in 2003, Dr. Goodrich has applied her knowledge of neural development and mouse genetics to the auditory system. Over the years, her laboratory has studied cellular and molecular mechanisms of circuit assembly in the spinal cord, hindbrain, retina, and inner ear. Currently, the primary focus is the formation of reciprocal connections between the cochlea and the auditory brainstem, with projects investigating the development and maturation of diverse spiral ganglion neuron (SGN) subtypes; heterogeneity among olivocochlear neurons and their interactions with SGNs; the influence of glia on cochlear wiring and function; and the organization and function of SGN inputs onto octopus cells in the cochlear nucleus complex. Dr. Goodrich was appointed Professor of Neurobiology in 2015 and has served as the Scientific Director for the Hearing Restoration Project at the Hearing Health Foundation since 2021.

When: Wednesday, October 26th at 4:00 PM Eastern

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Dr. Ronna Hertzano : 'Illuminating Inner Ear Development, Function and Protection with a Multi-Omic Torch'

Dr. Ronna Hertzano's talk was titled 'Illuminating Inner Ear Development, Function and Protection with a Multi-Omic Torch'.


Ronna Hertzano, MD, PhD, is a Professor of Otolaryngology Head and Neck Surgery, University of Maryland School of Medicine (UMSOM). Dr. Hertzano's clinical practice focuses on the diagnosis and treatment of diseases of the ear, with an emphasis on hearing restoration. Translationally, her goal is to make significant contributions towards the treatment of congenital and acquired auditory and vestibular dysfunction ( Towards hearing restoration, she works to unravel the regulatory signaling cascades that lead to the proper development of the ear and specifically the hair cells. She leads a collaborative team that develops and applies a variety of approaches for cell type-specific multi-omic analyses of the ear followed by state-of-the art informatic analysis to identify key regulators of gene expression in hair cell development, and cell type-specific signaling cascades in acquired hearing loss (e.g., noise induced hearing loss). To facilitate dissemination, sharing and analysis of multi-omic data Dr. Hertzano is the founder of the gEAR portal –gene Expression Analysis Resource ( Finally, Dr. Hertzano has a strong interest in mentorship and training of the next generation of clinicians, scientists and clinician-scientists.

When: Wednesday, Novemeber 30th at 12:00 PM Eastern

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Dr. William Brownell: 'From Sound to Action Potentials – A Tour of the Inner Ear'

Dr. William Brownell, Emeritus Professor at College of Medicine, speaks as the first presenter in the new ARO Seminar Series. His talk was titled 'From Sound to Action Potentials – A Tour of the Inner Ear'.

Dr. Bill Brownell is professor emeritus at the Baylor College of Medicine, Houston, TX where he held the Jake and Nina Kamin Chair of Otorhinolaryngology. Previously held appointments were at the University of Florida, Gainesville, FL, and the Johns Hopkins School of Medicine, Baltimore, MD. He spent two years (1965-1966) teaching science and mathematics in Nigeria with the United States Peace Corps between his undergraduate training in physics and graduate training in physiology at the University of Chicago, Chicago, IL. He is a Fellow of the Acoustical Society of America and a past president of the Association for Research in Otolaryngology. His research focus is on the electromechanics of hearing.

This session was moderated by ARO President-Elect, Dr. John Oghalai.

When: Thursday, September 17th at 5PM CT


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Dr. Jenny Stone: 'Regeneration of Hair Cells After Damage: A Historical Perspective and an Update on Mammals'


Dr. Jenny Stone is a Professor in the Department of Otolaryngology-Head and Neck Surgery at the University of Washington School of Medicine. Her research focuses on cellular and molecular mechanisms that control the development and regeneration of hair cells, the sensory receptors for hearing and balance. She studies both avian and mammalian animal models.

This session was moderated by, Dr. Mark Warchol.

When: Thursday, November 12th at 6:00 PM ET.


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Dr. Anthony Peng: 'Observations During the Study of Hair Cell Mechanotransduction'

Dr. Anthony Peng is an Assistant Professor in the Department of Physiology and Biophysics at the University of Colorado Anschutz Medical Campus. His lab is focused on studying the mechanisms of how the auditory sensory hair cells, the fastest mechanoreceptors in the body, transduce sound into electrical signals for the brain to process and interpret. To study the fast-mechanical responses of hair cells, Dr. Peng developed high-speed stimulators and high-speed imaging techniques to capture the kinetics of these exquisitely fast mechanoreceptors. Prior to starting his lab, Dr. Peng trained at Stanford University and in the Speech and Hearing Bioscience and Technology Program at Harvard and MIT.

This session was moderated by, Dr. Artur Indzhykulian.

When: Thursday, October 15th at 12:00 PM ET.

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Hearing loss can significantly disrupt the ability of children to become mainstreamed in educational environments that emphasize spoken language as a primary means of communication. Similarly, adults who lose their hearing after communicating using spoken language have numerous challenges understanding speech and integrating into social situations. These challenges are particularly significant in noisy situations, where multiple sound sources often arrive at the ears from various directions. Intervention with hearing aids and/or cochlear implants (CIs) has proven to be highly successful for restoring some aspects of communication, including speech understanding and language acquisition. However, there is also typically a notable gap in outcomes relative to normal-hearing listeners. Importantly, auditory abilities operate in the context of how hearing integrates with other senses. Notably, the visual system is tightly couples to the auditory system. Vision is known to impact auditory perception and neural mechanisms in vision and audition are tightly coupled, thus, in order to understand how we hear and how CIs affect auditory perception we must consider the integrative effects across these senses.

We start with Rebecca Alexander, a compelling public speaker who has been living with Usher’s Syndrome, a genetic disorder found in tens of thousands of people, causing both deafness and blindness in humans. Ms. Alexander will be introduced by Dr. Jeffrey Holt, who studies gene therapy strategies for hearing restoration. The symposium then highlights the work of scientists working across these areas. Here we integrate psychophysics, clinical research, and biological approaches, aiming to gain a coherent understanding of how we might ultimately improve outcomes in patients. Drs. Susana Martinez-Conde and Stephen Macknik are new to the ARO community, and will discuss neurobiology of the visual system as it relates to visual prostheses. Dr. Jennifer Groh’s work will then discuss multi-sensory processing and how it is that vision helps us hear. Having set the stage for thinking about the role of vision in a multisensory auditory world, we will hear from experts in the area of cochlear implants. Dr. René H Gifford will discuss recent work on electric-acoustic integration in children and adults, and Dr. Sharon Cushing will discuss her work as a clinician on 3-D auditory and vestibular effects. Dr. Matthew Winn will talk about cognitive load and listening effort using pupillometry, and we will end with Dr. Rob Shepherd’s discussion of current work and future possibilities involving biological treatments and neural prostheses. Together, these presentations are designed to provide a broad and interdisciplinary view of the impact of sensory restoration in hearing, vision and balance, and the potential for future approaches for improving the lives of patients.

Kirupa Suthakar, PhD - Dr Kirupa Suthakar is a postdoctoral fellow at NIH/NIDCD, having formerly trained as a postdoctoral fellow at Massachusetts Eye and Ear/Harvard Medical School and doctoral student at Garvan Institute of Medical Research/UNSW Australia.  Kirupa's interest in the mind and particular fascination by how we are able to perceive the world around us led her to pursue a research career in auditory neuroscience.  To date, Kirupa's research has broadly focused on neurons within the auditory efferent circuit, which allow the brain to modulate incoming sound signals at the ear.  Kirupa is active member of the spARO community, serving as the Chair Elect for 2021.



I began studying the vestibular system during my dissertation research at the Università di Pavia with Professors Ivo Prigioni and GianCarlo Russo. I had two postdoctoral fellowships, first at the University of Rochester with Professor Christopher Holt and then at the University of Illinois at Chicago with Professors Jonathan Art and Jay Goldberg.

My research focuses on characterizing the biophysics of synaptic transmission between hair cells and primary afferents in the vestibular system. For many years an outstanding question in vestibular physiology was how the transduction current in the type I hair cell was sufficient, in the face of large conductances on at rest, to depolarize it to potentials necessary for conventional synaptic transmission with its unique afferent calyx.

In collaboration with Dr. Art, I overcame the technical challenges of simultaneously recording from type I hair cells and their enveloping calyx afferent to investigate this question. I was able to show that with depolarization of either hair cell or afferent, potassium ions accumulating in the cleft depolarize the synaptic partner. Conclusions from these studies are that due to the extended apposition between type I hair cell and its afferent, there are three modes of communication across the synapse. The slowest mode of transmission reflects the dynamic changes in potassium ion concentration in the cleft which follow the integral of the ongoing hair cell transduction current. The intermediate mode of transmission is indirectly a result of this potassium elevation which serves as the mechanism by which the hair cell potential is depolarized to levels necessary for calcium influx and the vesicle fusion typical of glutamatergic quanta. This increase in potassium concentration also depolarizes the afferent to potentials that allow the quantal EPSPs to trigger action potentials. The third and most rapid mode of transmission like the slow mode of transmission is bidirectional, and a current flowing out of either hair cell or afferent into the synaptic cleft will divide between a fraction flowing out into the bath, and a fraction flowing across the cleft into its synaptic partner.

The technical achievement of the dual electrode approach has enabled us to identify new facets of vestibular end organ synaptic physiology that in turn raise new questions and challenges for our field. I look forward with great excitement to the next chapter in my scientific story.


Charles C. Della Santina, PhD MD is a Professor of Otolaryngology – Head & Neck Surgery and Biomedical Engineering at the Johns Hopkins University School of Medicine, where he directs the Johns Hopkins Cochlear Implant Center and the Johns Hopkins Vestibular NeuroEngineering Laboratory.

As a practicing neurotologic surgeon, Dr. Della Santina specializes in treatment of middle ear, inner ear and auditory/vestibular nerve disorders. His clinical interests include restoration of hearing via cochlear implantation and management of patients who suffer from vestibular disorders, with a particular focus on helping individuals disabled by chronic postural instability and unsteady vision after bilateral loss of vestibular sensation. His laboratory’s research centers on basic and applied research supporting development of vestibular implants, which are medical devices intended to partially restore inner ear sensation of head movement. In addition to that work, his >90 publications include studies characterizing inner ear physiology and anatomy; describing novel clinical tests of vestibular function; and clarifying the effects of cochlear implantation, vestibular implantation, superior canal dehiscence syndrome and intratympanic gentamicin therapy on the inner ear and central nervous system.  Dr. Della Santina is also the founder and CEO/Chief Scientific Officer of Labyrinth Devices LLC, a company dedicated to bringing novel vestibular testing and implant technology into routine clinical care.

Andrew Griffith received his MD and PhD in Molecular Biophysics and Biochemistry from Yale University in 1992. He completed his general surgery internship and a residency in Otolaryngology-Head and Neck Surgery at the University of Michigan in 1998. He also completed a postdoctoral research fellowship in the Department of Human Genetics as part of his training at the University of Michigan. In 1998, he joined the Division of Intramural Research (DIR) in the National Institute on Deafness and Other Communication Disorders (NIDCD). He served as a senior investigator, the chief of the Molecular Biology and Genetics Section, the chief of the Otolaryngology Branch, and the director of the DIR, as well as the deputy director for Intramural Clinical Research across the NIH Intramural Research Program. His research program identifies and characterizes molecular and cellular mechanisms of normal and disordered hearing and balance in humans and mouse models. Two primary interests of his program have been hearing loss associated with enlargement of the vestibular aqueduct, and the function of TMC genes and proteins. The latter work lead to the discovery that the deafness gene product TMC1 is a component of the hair cell sensory transduction channel. Since July of 2020, he has served as the Senior Associate Dean of Research and a Professor of Otolaryngology and Physiology in the College of Medicine at the University of Tennessee Health Science Center.

Gwenaëlle S. G. Géléoc obtained a PhD in Sensory Neurobiology from the University of Sciences in Montpellier (France) in 1996. She performed part of her PhD training at the University of Sussex, UK where she characterized sensory transduction in vestibular hair cells and a performed a comparative study between vestibular and cochlear hair cells. Gwenaelle continued her training as an electrophysiologist at University College London studying outer hair cell motility and at Harvard Medical School studying modulation of mechanotransduction in vestibular hair cells. As an independent investigator at the University of Virginia, she expanded this work and characterized the developmental acquisition of sensory transduction in mouse vestibular hair cells, the developmental acquisition of voltage-sensitive conductances in vestibular hair cells and the tonotopic gradient in the acquisition of sensory transduction in the mouse cochlea. This work along with quantitative spatio-temporal studies performed on several hair cell mechanotransduction candidates lead her to TMC1 and 2 and long-term collaborations with Andrew Griffith and Jeff Holt. Dr. Géléoc is currently Assistant Professor of Otolaryngology, at Boston Children’s Hospital where she continues to study molecular players involved in the development and function of hair cells of the inner ear and develops new therapies for the treatment of deafness and balance, with a particular focus on Usher syndrome.

Jeff Holt earned a doctorate from the Department of Physiology at the University of Rochester in 1995 for his studies of inward rectifier potassium channels in saccular hair cells.  He went on to a post-doctoral position in the Neurobiology Department at Harvard Medical School and the Howard Hughes Medical Institute, where he characterized sensory transduction and adaptation in hair cells and developed a viral vector system to transfect cultured hair cells.  Dr. Holt’s first faculty position was in the Neuroscience Department at the University of Virginia.  In 2011 the lab moved to Boston Children’s Hospital / Harvard Medical School.  Dr. Holt is currently a Professor in the Departments of Otolaryngology and Neurology in the F.M. Kirby Neurobiology Center.  Dr. Holt and his team have been studying sensory transduction in auditory and vestibular hair cells over the past 20 years, with particular focus on TMC1 and TMC2 over the past 12 years.  This work lead to the discovery that TMC1 forms the hair cell transduction channel.  His work also focuses on development gene therapy strategies for genetic hearing loss.