About the Researchers

Lendra Friesen is an Assistant Professor in the Department of Speech, Language and Hearing Sciences at the University of Connecticut.  She heads the Cochlear Implant Brain and Behavior Laboratory, which she founded in 2014.  She received certification as a clinical audiologist before receiving her PhD and has conducted research on hearing and cochlear implants for over 25 years.  Her research aims to combine electrophysiological and behavioral methods to understand where deficits occur in auditory coding, for example how age effects the ability to recognize the emotions expressed by a speaker.

Robert Morse is a consultant biomedical engineer.  His research is focused on computational modelling, neural coding, and the development of stochastic cochlear implant coding strategies.  He has recently been involved in the testing of a middle-ear microphone for a totally implantable cochlear implant and is interested in developing technology and infrastructure to expand the use of cochlear implants and hearing aids in lower-income countries.

About the Research

Development of information-theoretic approach for the analysis of auditory evoked potentials: quantifying the effects of age, disease, and congenital conditions at the midbrain and cortex

This project involves development of a novel method to calculate the amount of information conveyed by auditory evoked potentials — electrical signals that reflect the synchronized response of neurons in the auditory pathway to sound.  We are interested in the effects of age, disease and congenital conditions on midbrain and cortical potentials, which can both be recorded from electrodes on the scalp.  The information measure provides a measure of fidelity — how accurately the evoked potentials reflect acoustic features of the stimulus.  When used in studies that use the same participants for behavioral measures, e.g. speech comprehension and emotion recognition, the information measure will give insight into where breakdowns in auditory processing occur. This has consequences for the remedial steps that can be taken to enhance performance.  We will validate the method with younger and older participants using stimuli expected to show age effects and comparison with behavioral data.

About the Researcher

Dr. Parveen Bazard is an Assistant Professor (Research) in the Medical Engineering Department, University of South Florida (USF), in Tampa. His doctoral research focused on development of second-generation neural stimulation (Nanomaterials-enabled optical stimulation) for applications in auditory and sensorineural prosthetic devices. Since obtaining his PhD, he has expanded his horizons in various dimensions of auditory pathologies, with a special focus on age-related hearing loss (ARHL), such as identifying novel biomarkers of the aging auditory system, cochlear drug delivery, and developing diagnostic imaging protocols for the inner ear. His research interests include nanomaterials, electrophysiology, neural engineering, and research audiology.

About the Research

Developing Novel Therapeutic Interventions for Age-related Hearing Loss

Our growing older population presents us with significant new medical challenges due to declines of various body systems/organs. Auditory declines due to aging (age-related hearing loss – ARHL) is one such highly-prevalent challenge. Like other body systems, our hearing diminishes with age, affecting most people by age 60. There are both health and social implications associated with ARHL. ARHL is linked to other health problems, such as a pre-disposition to dementia, depression, distress, and loneliness. It also decreases the ability to live independently, increasing dependence on family and/or community support. There is no way to prevent or reverse ARHL, and currently, there is no FDA approved drug for its treatment. In the present grant, we propose to develop a therapeutic intervention for ARHL; with a primary focus on L-ergothioneine – a natural occurring dietary amino acid that has been found to be beneficial for treating other aging diseases.

About the Researcher

Nurunisa Akyuz received her B.A. from Princeton University in 2005 majoring in Physics and M.Sc. in Clinical Neurology from the University of Oxford. After receiving her PhD in Biophysics from Weill Cornell Medical School in 2014, she trained as a postdoc with David P. Corey at Harvard Medical School. In 2020, she received an NIDCD Early Career Research (ECR) R21 Award, which supports research from scientists who are beginning to establish an independent research career.

About the Research

A Structural Basis for Calcium Regulation of TMC1 Gating

Within the cochlea, dedicated sensory receptor cells called ‘hair-cells’ are responsible for the conversion of the sound-induced mechanical vibrations into electrical signals. These cells are named after the ‘bundles’ of hair-like protrusions on their apical surfaces. When the cochlea is excited by sound, vibrations of the inner ear fluids deflect the hairbundles. This leads to ion channel activity, generating receptor currents. A hallmark of this
mechanosensory channel activity is adaptation: the currents rapidly decline during sustained stimulus. This adaptation process is thought to contribute to the way hair-cells actively amplify and fine-tune sound-induced mechanical stimuli via a Ca2+-dependent feedback mechanism. Nevertheless, a specific Ca2+- binding site within the channel is yet to be identified. Successful completion of the project will investigate the location of putative calcium binding sites within the channel and set the stage for testing hypotheses about how Ca2+-dependent fast adaptation drives frequency tuning in the cochlea.

About the Researcher

Melissa Ghulam-Smith, MD, PhD is an Otolaryngology Resident at the University of Miami. As a T32-resident, she is granted one year to perform research in an area of interest. She is interested in the effects of mTBI on the inner ear and in novel therapeutics that can treat the debilitating symptoms of dizziness and loss of balance.

About the Research

Vestibular functional and histological changes in a blast induced-mTBI rat model

Mild traumatic brain injury also known as a concussion is the result of trauma to the brain. Exposure to a blast is a form of trauma that causes an increase in the surrounding air pressure that can damage the ears and brain. The ears are particularly sensitive to overpressure as they are open to the surrounding air. Common symptoms after mTBI are dizziness or balance problems. This is due to damage to the vestibular system which is in close proximity to the auditory system in the inner ear. The effects of blast on the vestibular system are poorly understood. This project uses a rodent blast model to examine the functional and anatomical vestibular damage associated with blast exposure to better understand the mechanisms that lead to acute and chronic symptoms. This will help us determine the best possible diagnostic and treatment strategies for those affected.

About the Researcher

Dr. Anoop Jadadeesh is a Postdoctoral fellow at the Auditory Neuroscience Laboratory (PI: Nina Kraus), Northwestern University.  He completed his PhD in Audiology from the All India Institute of Speech and Hearing, India. His research focuses on the age-related differences in auditory function using behavioral and electrophysiological (brainstem and cortical) approaches. In particular, he is interested in understanding how listeners across the lifespan (and specifically their brains), with varying degrees of hearing acuity, perceive and process speech and musical sounds.

About the Research

Neural basis of music perception in individuals with hearing loss

Hearing loss (HL) reduces an individual’s ability to recognize aspects of music (pitch, rhythm, timbre, etc.) as well as the pleasure and engagement in listening to music. In this project, we search for HL-related changes in the neural mechanisms associated with sound (music) perception using the Frequency Following Response (FFR) – a response that can be evoked by most sounds (including music). While largely of midbrain origin, the FFR reflects the contribution of the vast hearing brain that includes how we think, feel, move, and integrate our senses. Specifically, the project will determine if HL changes key aspects of how the brain responds to music, and if these changes can account for why individuals with hearing loss often report diminished engagement and enjoyment of music. Moreover, the FFRs recorded from an individual’s brain can be converted back to sound, providing another dimension to understand and quantify the changes in brain response fidelity due to HL. Listening to the brain’s response to music should further inform us about the nature of the changes imparted by the hearing loss.

About the Researcher

Colin Johnson obtained a PhD from the University of Illinois Department of Chemistry. Otoferlin has been his focus of study starting with a postdoctoral in Dr. Ed Chapman’s lab at the University of Wisconsin.

About the Research

Characterization of the deafness-associated hair cell protein otoferlin

Over 200 pathogenic mutations in the gene otoferlin result in hearing loss, accounting for up to 8% of all forms of prelingual autosomal recessive hearing loss. Although otoferlin is essential for sensory hair cells to transmit sensory information at the synapse to neurons, the function of otoferlin at the synapse remains unclear. This lack of functional information prevents better understanding of how hair cells encode sound information. It also limits our understanding of the relationship between a pathogenic mutation and the severity of hearing loss exhibited. To better understand otoferlin, we will experimentally measure otoferlin and otoferlin mutant protein to determine the molecular basis for deafness-associated mutations. Our studies will identify the role  of otoferlin in neurotransmitter release from sensory hair cell synapses and determine the basis for why certain mutations in OTOF result in pathology.

About the Researchers

Dr. Kamal Sen, Associate Professor, Biomedical Engineering, Boston University. has expertise in brain mechanisms underlying auditory scene analysis (ASA) and brain-inspired algorithms for ASA to improve hearing assistive devices.

Dr. David Boas, Professor, Biomedical Engineering, Boston University, led the development of one of the first imaging systems using continuous-wave near infrared spectroscopy (NIRS) for functional imaging and an expert on multi-modal fNIRS/EEG systems.

Dr. Laura Lewis, Assistant Professor, Biomedical Engineering, Boston University, has expertise in EEG and neural signal processing.

Dr. Virginia Best, Research Associate Professor, Speech Language and Hearing Sciences, Boston University, has expertise in how spatial hearing supports orientation and communication in challenging realworld situations, human auditory psychophysics, hearing loss and hearing assistive devices.

 About the Research

 Investigating Auditory Scene Analysis in Humans with Wearable fNIRS and EEG

Imagine a conversation with a friend at a noisy café in the presence of other people talking, music playing and the noisy traffic outside. This challenging problem is referred to as the “cocktail party problem” or “auditory scene analysis”. Although many normal hearing listeners can do this, hearing impaired listeners find such scenes overwhelming and debilitating. Understanding how the normal brain solves this problem, may lead to better treatments and improvements of hearing assistive devices, improving the quality of life for the hearing impaired. However, relatively little is known about brain mechanisms that enable the solution to the problem. This project will measure brain signals in humans using a wearable device, while they focus on a single speaker in the presence of other speakers talking. This project will advance our understanding of how the normal brain singles out a particular sound in noisy settings, and may improve hearing assistive devices.

About the Researcher

Jordan Varghese is a resident physician-scientist trainee in the Department of Otolaryngology at Washington University in St. Louis. He obtained an MD from Emory University and a BS in Biomedical Engineering from the Georgia Institute of Technology. His primary focus is clinical outcomes research to improve management of hearing loss.

About the Research

Transtympanic electrocochleography: Characterizing residual cochlear function in sudden sensorineural hearing loss to better predict outcomes

Sudden deafness is a rapid loss of hearing that occurs over the course of a few days and each year 1 in 5000 people will have an episode. Even months after the event, around half of these cases will not have significant hearing recovery. Discussion with patients on the degree they can expect to get their hearing back is challenging and prognosis is limited by currently available clinical information (e.g., subjective hearing tests, simultaneous symptoms, time before steroid treatment). Electrocochleography (ECochG), a measure of the electrical activity of the ear in response to sound, has been effectively used to diagnose inner ear diseases and measure the degree of residual hearing function. This study will measure ECochG in clinic for patients with sudden deafness. The goal will be to identify ECochG as an important predictor of hearing outcomes in sudden deafness and improve patient-specific counseling on hearing recovery expectations.