About the Researcher

Jasleen Singh is a Postdoctoral Fellow at Northwestern University. She recently completed her PhD at Syracuse University and is a clinical audiologist. Her research focuses on ways to improve the rate of hearing aid use among older adults. More specifically, she is interested in exploring how new models of hearing healthcare can impact hearing aid use and outcomes.

About the Research

The Influence of Patient Psychosocial Behaviors on Hearing Aid Use and Outcomes in an Over-the-Counter Delivery Model
An individual’s health psychology influences hearing aid use and outcomes in a traditional provider-driven model of hearing healthcare. A new paradigm of Over-the-Counter (OTC) Hearing Aids is upon us. The impact of health psychology on hearing aid use and outcomes is completely unexplored in this new model of hearing healthcare. It is also unknown if patient health psychology and OTC hearing aid outcomes can be improved using virtual post-fitting support. Thus, we will compare how patient health psychology and hearing aid outcomes change over a hearing aid trial in an OTC model versus provider-driven model of hearing healthcare with and without supplemental virtual post-fitting support.

About the Researcher

Ryan Bartholomew is a resident in the Harvard otolaryngology program. He received his MD from Harvard Medical School. Previously he investigated the contributions of the basal ganglia to behavior using optogenetics and 3-dimensional motion tracking in the Yin Laboratory at Duke University. He is spending his NIH-T32 fellowship in the laboratory of Dr. Daniel Lee, MD and Chris Brown, PhD at Massachusetts Eye and Ear. He is additionally mentored by Dr. Shelley Fried, PhD and Julie Arenberg, MS, PhD as he studies the feasibility of a magnetic micro-coil based cochlear implant alongside his co-investigators Jae-Ik Lee, PhD and Victor Adenis, PhD.

About the Research

Magnetic stimulation of the cochlear nerve: Foundation for a next-generation cochlear implant
The cochlear implant (CI) provides sound perception to patients with hearing loss through electric stimulation of auditory neurons by electrodes surgically implanted in the hearing organ—the cochlea. However, understanding conversations in background noise and appreciation of music is challenging with this device. This is largely because electric stimulation is unable to selectively activate precise groups of auditory neurons. Our group recently demonstrated in a mouse model that, compared to electric stimulation, magnetic stimulation with a micro-coil more selectively stimulates hearing neurons. These results suggest that a magnetic micro-coil-based CI may offer improved hearing outcomes compared to current devices. To further evaluate this possibility, we will evaluate magnetic stimulation delivered by micro-coils in different orientations and positions within the cochlea of guinea pigs. We hope these experiments will lay the foundation for development of a next generation CI which will provide deaf individuals improved ability to understand the speech of their loved ones and improved enjoyment of music.

About the Researcher

Nesrine Benkafadar is a postdoctoral fellow in Dr. Stefan Heller’s lab at Stanford University. She obtained her Ph.D. from the University of Montpellier (France) for her work on establishing a functional interaction between oxidative stress, DNA damage, and cochlear cell aging. Her current research focuses on characterizing the series of events that trigger hair cell regeneration in the damaged avian cochlea. Her goal is to investigate key trigger genes to induce adult mammalian supporting cells in the damaged cochlea to reenter the cell cycle toward hair cell regeneration.

About the Research

Key triggers of hair cell regeneration
Aminoglycosides are a class of clinically essential antibiotics used worldwide to treat life-threatening infections. Aminoglycosides, however, have severe ototoxic side effects and cause sensory hair cell loss resulting in permanent hearing loss in a significant number of patients. Lost mammalian hair cells are not regenerated, unlike in non-mammals such as chickens. The mechanism by which the normally mitotically quiescent chicken cochlea orchestrates a coordinated regenerative program is unknown. This study aims to identify the triggers that initiate and execute hair cell regeneration in the chicken. This information will then be used to inform a functional investigation of pathways active during mammalian cochlear hair cell death and to identify signaling pathways that prevent natural hair cell regeneration in the mammalian cochlea. The work aims to provide new insight into developing novel therapies for hearing loss.

About the Researchers

Ignacio García Gómez is a Research Assistant Professor at Northwestern University Feinberg School of Medicine. He received his PhD from the Complutense University of Madrid (Spain). His training dedicated to the understanding of the benefits of stem cell therapy in diverse pathologies have given him a very valuable training to apply in the hearing field. His research at Northwestern University focuses on cochlear inner and outer hair cell development and on the pathophysiologycal mechanisms of hearing loss.
Jaime García-Añoveros is a Professor of Anesthesiology, Neurology and Neuroscience, and a fellow of the Knowles Hearing Center, at Northwestern University. His past research explored the function, dysfunction, development and degeneration of sensory receptor cells and neurons of somatosensory ganglia, nose, and inner ear. His recent research is centered on the differential development, and innervation, of cochlear inner vs outer hair cells.

About the Research

Differential hair cell death susceptibility to age and noise
IHCs and OHCs are the principal actors in the sense of hearing. Hair cells die due to age and intense noise exposure, causing irreversible deafness, with OHCs much more vulnerable to damage than IHCs and mostly responsible for hearing loss. With the aim of studying the differential sensitivity to trauma of OHCs and IHCs, we propose a novel approach using Insm1 mutant mice. These mutants have IHCs in the outer compartment, the natural location of the OHCs, and this gives us unique experimental conditions to resolve whether OHCs are more vulnerable than IHCs because of their location and environment, or because of their intrinsic cell characteristics. The conclusions extracted from this study will contribute to understand the pathophysiology mechanisms of hearing loss and may have implications to developing treatments to prevent it.

About the Researcher

David Lee, MD received his medical degree from University of California, San Francisco, and is now a T32 resident in Otolaryngology at Washington University in St. Louis. His research focuses on advancing techniques in inner ear imaging to improve management of hearing instability disorders.

About the Research

Optical Coherence Tomography of Inner Ear Structures: Using Novel Imaging Technology to Investigate Meniere’s Disease and Sudden Sensorineural Hearing Loss
Hearing instability disorders, like Meniere’s disease and sudden sensorineural hearing loss (SSNHL), are poorly understood and inadequately treated. Steroids have been standard of care for decades, but their results have been inconsistent. Progress towards improving patient outcomes has been challenged by an inability to detect pathology within the inner ear, where hearing instability disorders are thought to occur. Currently, otolaryngologists rely on patient history and audiograms to guide clinical decisions. This makes diagnosis ambiguous and monitoring response to treatment difficult.

Imaging is an attractive method for monitoring disorders of hearing instability because it is non-invasive and provides objective data. However, current imaging techniques like CT and MRI are unable to adequately view the microstructures within the inner ear. Our project seeks to use optical coherence tomography, a light-based imaging modality, to view structures in the inner ear to assist with diagnosing and monitoring hearing instability disorders.
 

About the Researcher

Xin Luo is an Assistant Professor of Speech and Hearing Science in the College of Health Solutions at Arizona State University, where he directs the Auditory Implant Lab. He studies how cochlear implant users and normal-hearing listeners use different cues to perceive ecologically valid dynamic pitch changes and designs signal processing, electrical stimulation, and aural rehabilitation strategies to help cochlear implant users perform better in pitch-related listening tasks. He received his PhD in electrical engineering from University of Science and Technology of China and his post-doc training in speech and hearing science at House Ear Institute in Los Angeles.

About the Research

Neural Health and Pitch Perception with Cochlear Implants
The health status of auditory nerve cells may contribute to the variable auditory performance of individual cochlear implant (CI) users. Based on findings in animal studies, several neural health measures have been proposed for use in human patients. However, different neural health measures are not correlated with each other, possibly because they reflect different aspects of neural health such as the conditions of peripheral process and central axon. Also, they are not correlated with speech recognition scores that rely on not only neural coding of acoustic cues but also top-down cognitive processing. This project will examine the relationships between different neural health measures and pitch sensitivity to changes in place and rate of CI stimulation on different electrodes of human CI users. The findings could validate the neural health measures useful for CI outcome prediction and CI fitting customization, and reveal important neural health factors for pitch perception with CIs.

About the Researcher

Emma Martin, MD is a second-year resident in the Department of Otolaryngology – Head and Neck Surgery at the University of Illinois at Chicago. She completed her undergraduate medical training with honors at the University of Illinois at Chicago. She has a Bachelor of Arts in Biological Sciences from Northwestern University.

About the Research

Contributions of vocal tract length to cochlear implant users’ perception of vocal pitch
Patients who have received cochlear implants tend to have difficulty identifying vocal pitch, an ability that is used to determine speaker gender and distinguish different speakers in a noisy environment. There are two main factors that contribute to a normal-hearing person’s perception of vocal pitch. One is the fundamental frequency of the speaker’s voice, which is controlled by the length and tension of the vocal cords. The other is the resonance of the sound after it is produced by the vocal cords, which is largely determined by the length of the speaker’s vocal tract. The purpose of this study is to determine if changes in vocal tract length alter cochlear implant users’ pitch perception.

About the Researcher

Xiaodong Tan, PhD, a research assistant professor in the Department of Otolaryngology at Northwestern University, earned his PhD degree at Creighton University and received his postdoctoral training at University of Wisconsin-Madison and Northwestern University. Dr. Tan contributed on the structural and functional evolution of prestin and the development of infrared laser-based cochlear implants. Currently, his research interest is hearing protection against multiple insults including drug, noise, and age.

About the Research

Ototoxic Effects of Bound and Unbound Cisplatin
Cisplatin ototoxicity (CO) contributes to ~100-300 thousand new hearing impairment cases annually among cancer patients in the US with no approved treatment available in the clinic. Unbound cisplatin is active and binds to proteins and DNA once gets into the cochlea, causing damages particularly the loss of outer hair cells (OHCs). However, it is unclear whether the damage on OHCs is a direct or indirect effect of CO, since no direct evidence of the presence of cisplatin in OHCs is available. Understanding the mechanism and metabolism of cisplatin is important for developing the best strategy for hearing protection in chemotherapy. Our recent works using X-ray fluorescence microscopy (XFM) have shed light on this puzzle. In this study, XFM will be used to show the distribution of cisplatin in the cochlea with a nanometer resolution and femtogram/cm2 sensitivity. The potentially different roles of bound and unbound cisplatin will also be investigated

About the Researcher

Amit Walia is a resident in the Department of Otolaryngology at Washington University in St. Louis. He received his M.D. with honors from the University of Illinois in Chicago. His research is focused on using electrocochleography to improve cochlear implant outcomes.

About the Research

Using electrocochleography to build a prediction model for speech-perception performance in noise after cochlear implantation
Cochlear implantation (CI) has become an effective treatment option over the last three decades for those with severe-to-profound hearing loss. Although many patients do well after implantation, performance as measured by speech perception outcomes is highly variable and remains largely unexplained. Recognizing factors that may limit speech perception performance after implantation would be useful in counseling patients preoperatively, tailoring a patient-specific aural rehabilitation pathway, and improving surgical approaches and customizing electrode designs. The goal of this research is to utilize electrocochleography to measure acoustically evoked electrical potentials from the cochlea and quantify residual cochlear function with the goal of predicting performance in quiet and background noise prior to electrode array insertion.

About the Researcher

Christine Mei, MD is a clinical resident and NIH/NIDCD T32 Interdisciplinary Research scholar at the University of Miami Department of Otolaryngology. She obtained her MD from the University of Miami Miller School of Medicine. Dr. Mei’s research is focused on cumulative effects of noise and CI in the inner ear.

About the Research

Hearing Preservation Effects of Therapeutic Hypothermia in a ‘Double-Insult’ Model of Cochlear Implantation in Noise-Exposed Cochleae
Noise exposure poses a significant but variable risk to hearing, depending on intensity, timing, and other factors of the noise insult. Cochlear implantation (CI) is often slotted for noise-induced hearing loss, yet the surgical trauma also poses a risk to hearing. These two insults, noise and surgical implantation, have not yet been studied in conjunction. This project aims to discover the cumulative effects of noise and CI on the inner ear. A ‘double-insult’ model will be created that will expose rats to noise and subsequent CI. Auditory brainstem response hearing testing will be performed through the insult sequence and cochleae will be collected for analysis of cells in the inner ear. A novel mild therapeutic hypothermia treatment protocol will also be explored in mitigation of the double-insult damage.