Our People

Jaime García-Añoveros, PhD

Professor, Anesthesiology, Neuroscience, Neurology

Bio

Our research focuses on cochlear development: how inner and outer sensory hair cells form, how they assemble into the cellular mosaic that is the organ of Corti, and how they communicate with the brain.

Two cell types in the cochlea, inner (IHC) and outer (OHC) hair cells, play complementary roles in hearing. These cells are produced in an early developmental period, but then die throughout our lives – because of age, noise or ototoxic drugs – and this results in irreversible deafness. Attempts to create new hair cells from cochlear supporting cells are under way, but we still are learning how to generate IHCs and OHCs, each in their own appropriate location. Our main research contribution has been to clarify how and when this cellular dichotomy arises.

With this new knowledge, we aim to regenerate these inner and outer cells for the restoration of hearing. Eventually we hope to overcome the main barriers towards regenerative therapies for deafness: by generating IHCs and OHCs, assembling them with their appropriate partners, and reconnecting them to the brain.

Ann Bradlow, PhD

Professor of Linguistics

Bio

My scholarship focuses on the interface between linguistic knowledge and language function. Using multi-disciplinary approaches, including behavioral experimentation with human subjects, audio speech signal analysis, and statistical analysis of large corpora of multilingual speech recordings, my work has contributed to theoretical and practical advances in our understanding of the cognitive, perceptual, and acoustic manifestations of bilingualism and the nature of speech communication across a language barrier.

Bharath Chandrasekaran, PhD

Ralph and Jean Sundin Endowed Professor; Chair, Roxelyn and Richard Pepper Communication Sciences and Disorders

Bio

I am an auditory cognitive neuroscientist dedicated to a better understanding of human communication. My academic journey began in India, where I earned my bachelor's degree in Speech, Language, and Hearing Sciences. Eager to delve deeper into the neurobiological mechanisms of human communication, I pursued and obtained my PhD in Integrative Neuroscience from Purdue.

I am the director of the SoundBrain Lab, where we apply a systems neuroscience approach to investigate the computations, maturational constraints, and plasticity underlying the processing of complex auditory signals like speech. Over the past two decades, we've employed cutting-edge approaches to gain computational, algorithmic, and implementation-level understanding of how sounds are represented and mapped to behaviorally-relevant constructs in the human brain. From a clinical perspective, we hope to develop a richer understanding of the neurocognitive sources of individual differences in speech processing. We aim to develop optimized and neurobiologically-informed auditory training approaches for second language learning, learning impairments and auditory processing deficits.

Mary Ann Cheatham, PhD

Research Professor, Auditory Physiology

Bio

The work of our lab seeks to define the functional differences between the two populations of sensory receptor cells in the cochlea: outer and inner hair cells. After characterizing the gross cochlear potentials generated by groups of receptor cells, we perform intracellular recordings to describe single hair cell responses. Our discovery of prestin, the motor protein in outer hair cells, has led us to the study of the genetic basis of peripheral signal coding.

In addition to work on hair cells, we also study mutant mice with genetic defects to better understand the accessory structures in the cochlea. In mice where connections between the outer hair cells and the tectorial membrane are disrupted – sensitivity and frequency selectivity, the hallmarks of mammalian hearing, are lost. By manipulating the expression of several of the proteins that form this structure, we have learned how changing physical properties can impact hair cell stimulation.

The molecular characterization of structures that comprise the organ of Corti, the sense organ of hearing, provides a strong foundation for advances in the treatment of hearing loss and deafness. However, this translational science requires the integration of medical, clinical and research areas of our field. My collaborations with Knowles Fellows have allowed for developments that I would never have imagined when I began my studies in Audiology under the tutelage of Raymond Carhart.

Peter Dallos, PhD

Professor Emertius of Audiology, Otolaryngology and Biomedical Engineering, John Evans Professor of Neuroscience, Neurobiology & Physiology

Bio

Peter Dallos’s research explores the mammalian ear’s inner and outer hair cells. His lab has developed the now widely accepted idea that outer hair cells function as local amplifiers and are responsible for the ear’s sensitivity and frequency selectivity. A few years ago Dallos and his research team identified the molecule prestin, a novel motor protein unique to outer hair cells that helps these cells amplify sound. His current research involves examining the properties of prestin and the influence of modifications in prestin on hearing in mice.

Sumitrajit Dhar, PhD

Hugh Knowles Professor of Hearing Science

Bio

I study the soft sounds that cells in the inner ear make to understand vital aspects of our hearing. I use these sounds to detect the earliest signs of damage to the inner ear. I am seeking to understand why many adults who have hearing difficulties choose not to use hearing aids. Through both these lines of work, I hope to change how hearing difficulties in adults are diagnosed and treated.

Interacting with many scientists and clinicians has changed how I think about hearing and how I pursue scholarship. One particular workshop organized by the National Institutes of Health in 2009 on Affordable and Accessible Hearing Health Care changed the trajectory of my work. Attending this workshop made the bigger goals of my work crystal clear. We need to understand how our ears work so we can understand why they don't. And we need to understand the barriers that keep people away from hearing care so everyone who has hearing difficulty can find affordable ways of receiving such care.

I studied audiology and hearing science at the University of Mumbai, the Utah State University, and Purdue University. I have been at Northwestern University and been a Fellow of the Hugh Knowles Center since 2004.

Anne Duggan, PhD

Research Assistant Professor

Bio

My main research focus has been to understand how DNA-binding transcription factors (TFs) act within gene regulatory networks to generate neuronal diversity. I did my doctoral research in Marty Chalfie's lab at Columbia University, where I studied the roles of different types of TFs in the specification and differentiation of neuronal subtypes in the genetic model organism Caenorhabditis elegans.

At Northwestern, I have worked with Jaime García-Añoveros' research team to understand the molecular regulation of inner ear development in the mouse, with a focus on genes that regulate the specification and differentiation of the two types of mechanosensory hair cells of the organ of Corti, the inner hair cells and the outer hair cells. We have identified a TF that promotes outer hair cell development and spiral ganglion neurogenesis. More recently, we have identified and characterized the TF Tbx2 and demonstrated that it directs an inner hair cell transcriptional program as opposed to an outer hair cell transcriptional program. Our findings add to the existing knowledge of the gene regulatory networks necessary to generate hair cells.

We hope that an understanding of the molecular control of inner ear development will guide the development of hair cell regenerative therapies to address hearing loss.

Kazuaki Homma, PhD

Assistant Professor, Otolaryngology – Head and Neck Surgery

Bio

The remarkably complex inner ear converts sound and motions into electrical signals. It is not surprising that this intricate anatomy and function are easily impaired by mutations in various genes. Although advanced DNA sequencing technology has allowed the identification of new genetic variations associated with deafness at an unprecedented rate, the exact cause and role of many of them remain unclear. I am trying to understand the precise molecular and cellular mechanisms underlying the exquisite sensitivity and frequency selectivity of mammalian hearing.

My research focuses on experimentally characterizing genetic variations associated with hereditary hearing loss. By defining their exact role in causing deafness, I aim to understand how normal hearing is achieved. Thus, this research strategy addresses both fundamental biological questions and clinically relevant issues. The outcome of my research will help us identify truly pathogenic variants and develop potential clinical strategies to address them.

Alan G. Micco, MD, FACS

Professor, Otology/ Neurotology

Bio

I have expertise in diagnosing and treating disorders of the ear and related skull base structures. I also have an interest in clinical/ translational research endeavors.

I have always had a strong interest in research as it parlays into new and improved therapies for patients. I have always approached challenges with the idea that we can always do better. Collaborating with colleagues allows for an exchange of ideas and helps create an environment of academic excellence.

I hope our work leads to better clinical outcomes for patients with otologic and neurotologic disorders.

Diane Novak, AuD

Senior Lecturer and Clinic Assistant Director

Bio

Diane Novak is a Associate Clinical Professor in the Department of Communication Sciences and Disorders and serves as the Center for Audiology, Speech, Language, and Learning Director at Northwestern University. Diane is a certified audiologist with over 25 years of clinical experience. Dr. Novak's clinical work has focused on diagnosing and treating adults with hearing loss. She has special interests in the professional and clinical development of students, improving accessibility to hearing healthcare, and educating allied health professionals and consumers on the importance of prevention, identification, and treatment of hearing loss and balance issues. She is responsible for strategy, finance, marketing, and operations for all clinical services.

Claus-Peter Richter, MD, PhD

Professor, Otolaryngology, Otolaryngology Head and Neck Surgery; Biomedical Engineering; Communication Sciences and Disorders

Bio

My research interests relate to a better understanding of hearing and how it can be restored in the severely-to-profoundly deaf. Living on the edge between the bed and the bedside, my work includes basic sciences of hearing and medical device development.

My education as a physicist, physician, and physiologist has taken me far toward achieving cross-disciplinary excellence. Since 2004, I have been focused on the idea that stimulating neurons with light allows for more spatially selective activation of neurons. Implementing this novel method in cochlear implants would enable new devices to restore hearing in severely-to-profoundly deaf people at a higher fidelity and, subsequently, better performance in speech in noise, tonal language, and music perception.

Along my way, translating optical stimulation of neurons into a medical device, I used and touched many other scientific fields and disseminated my findings via manuscripts, patents, book chapters, and scientific abstracts and talks. I have co-founded several start-up companies developing code, procedures, and techniques for cochlear implants and hearing aids. My dream is to see the opto-electrical cochlear implant fulfill its promise and provide the expected benefit to the hearing impaired.

Kristy Riley, PhD, CCC-A, FAAA

AuD Program Director, Associate Clinical Professor

Bio

I had a student teacher in the 5 th grade who taught us the American Sign Language alphabet and a few rudimentary signs. From that day forward, I was determined to work in support of children with hearing loss and while I initially planned to pursue a career as an elementary school special education instructor, after taking a Hearing Science course, I immediately changed course to pursue Audiology. Upon graduating with my master’s degree, I practiced as a clinical pediatric audiologist at what is now Lurie Children’s Hospital in Chicago. For the last eight of my ten years there, I was fortunate to serve as the cochlear implant coordinator in the early days of pediatric cochlear implantation. Working with those children and their families served as the impetus for my doctoral work in language development in children with and without hearing loss. I completed my PhD at Northwestern in 2010 and was able to return to Northwestern as the Au.D. program director in 2011. My passion now is in developing the next generation of hearing healthcare professionals. I continually strive to create a positive, supportive, but challenging learning environment that prepares future hearing healthcare providers to serve their patients with high-quality evidence-based interventions couched in a patient-centered, culturally-competent care model.

Megan Roberts, PhD

Professor, Communication Sciences and Disorders

Bio

I conduct clinical trials of different variations of behavioral interventions to support communication in infants and toddlers who are Deaf or Hard of Hearing (DHH).

I started my career as a speech-language pathologist at an inclusive preschool for children with developmental delays. This front-line experience with families of children with developmental delays exposed gaps in the current knowledge and motivated me to pursue a doctoral degree.

I believe that every child has an important message to share with the world and that language is best learned during positive interactions between caregivers and children. This naturalistic approach along with my other job as a mother of two young children has informed my clinical practice and research, both of which focus on parent-mediated interventions for DHH children. Each of my studies began with a toddler who made me curious about how best to support their communication.

As a clinician scientist, I believe in being a bridge between science and practice. Ultimately, I would like to develop individualized early language interventions based on specific child and parent characteristics. I also want these interventions to be feasible and implemented on a wide scale.

Adrian Rodriguez-Contreras, PhD

Associate Professor

Bio

Adrián Rodríguez-Contreras, associate professor in the Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, joins Northwestern from City University of New York (CUNY), City College. His work focuses on neuroplasticity, neurophysiology, and how certain diseases affect the brain and our behavior—namely, the way we see and hear. Rodriguez-Contreras is the recipient of numerous grants and awards including multiple National Institutes of Health grants, the CCNY Harvey L. Karp Discovery Award in the Sciences, as well as a $1.2 million a year grant from the Department of Defense.

Mario Ruggero, PhD

Professor Emeritus, Hugh Knowles Chair in Hearing Sciences

Bio

Mario Ruggero studies all aspects of the ear, from the external ear to the auditory nerve. Ruggero’s research has shed light not only on how the normal ear works but also on what causes deafness and how it might be treated.

Jason Tait Sanchez, Ph.D., CCC-A, FAAA

Associate Professor, Communication Sciences and Disorders

Bio

My start as a music major in college does not exactly fall in line with activities that promote appropriate hearing health. But serendipitously, my potentially harmful passion for the drums nudged me from musician to audiologist. I enrolled in an elective class entitled "Introduction to Hearing Science" during my sophomore year in college. In the course description, I remember one area of focus being on hearing loss and prevention. Learning how the auditory system works and better protecting my hearing appealed to me. Within a year, I had completed nearly a third of the required coursework for a major in Communication Disorders, and as a result, I decided to shift gears and change majors. I haven't looked back since.

Throughout my education and training, I became interested in differential ways to diagnose hearing loss in difficult-to-test patient populations using electrophysiological methods. This interest initially led me to Kent State to work with an expert on the topic. However, my new advisor moved away from clinical electrophysiology research to focus more on science-based neurobiology research of bats…of all things! Unfortunately for me (or at least what I thought at the time), there was no other research lab at Kent State doing anything remotely related to my focus. As a result, I was suddenly faced with finding a new advisor or dropping out of the program entirely. Taking a leap of faith (or, perhaps, feeling like I had no other option), I decided to align with my advisor and hope for the best. Admittedly, I was not very excited about the change initially. Still, after I endured some tough lessons in basic biology and bites from the bats, I eventually got into the swing of things. I soon realized that I was on the correct research path, and I completed my PhD in Audiology and Neuroscience. I joined the Otolaryngology Department as a postdoctoral fellow at the University of Washington to equip myself for a better research career. There, I investigated developmental aspects of normal hearing function in the auditory brainstem of chickens (yes, I said chickens).

Today, my research focuses on the development of excitatory properties in neurons responsible for encoding temporal cues of sound. The results of my research will help audiologists better understand how the auditory system develops so that they can diagnose and treat disorders more effectively.

Jeffrey Savas, PhD

Assistant Professor, Neurology

Bio

My research is focused on proteins. Not the proteins in our diet but the proteins that function as the micromachines that carry out nearly all the cellular processes required for life. Rather than studying individual proteins one at a time, I study 100s or even 1000s at a time using mass spectrometry. This allows me to focus on groups of proteins that change in interesting ways during neurodegeneration, aging, and conditions that cause hearing loss. The main goal of my research is to determine how impaired protein quality control contributes to these processes. We are particularly interested in how impaired protein degradation affects synapses, the specialized cell junctions that allow neurons to communicate.

I found my passion for biochemistry and proteins during an undergraduate biochemistry course taught by a member of the National Academy of Sciences. The intricate and passionate manner this teacher spoke about proteins and macromolecules amazed me and sparked my lifelong interest in biological molecules. The depth of my knowledge and interest only grew from there during my Ph.D. and postdoctoral studies and as a faculty member today.

It would be a dream come true if our research could culminate in helping someone with neurodegeneration or hearing loss. We have made some progress toward this goal and have recently identified a small molecule that increases the expression level of "protein folding doctors" that can prevent noise-induced hearing loss in rodents. In the future, we hope to continue to work on translating this to human beings.

Jonathan Siegel, PhD

Associate Professor, Communication Sciences and Disorders

Bio

I study the structure and function of the auditory periphery because I find it a unique and fascinating sensory system. I seek to improve our understanding of how hearing works and the impairments it imposes when it is damaged. The goal is not only to help those with hearing impairments but also to satisfy curiosity.

I began working in the lab of Drs Russell Pfeiffer and Charles Molnar in the summer of my first year of graduate study at Washington University. I was thrilled to study responses of single cochlear neurons and to indirectly study the mechanics of the cochlea. I knew instantly that I'd found a perfect match between my background in physics, understanding of electronics and acoustics and our incredible ability to hear. I loved being part of a fantastic team of people with talents in biology, computers, engineering and theory.

I am a generalist. I find each stage of peripheral processing fascinating: the efficiency of the middle ear, the mechanics of the cochlea where sound-induced vibrations are amplified by the sensory hair cells, how the hair cells respond to the vibrations and transmit signals through highly specialized synapses with the sensory neurons and how hearing arises from the resulting neural population code.

My generalized interest in the auditory periphery motivates my teaching and I take great joy in inspiring the curiosity of my students. My broad focus has allowed me to see relationships between auditory processes that weren't obvious. I love working directly with my students, interacting with my colleagues at Northwestern and elsewhere, helping create something bigger than myself: a community of scholars of hearing.

Pamela Souza, PhD

Professor

Bio

Pamela Souza received her bachelor's degree in Communication Disorders from the University of Massachusetts at Amherst, followed by masters and PhD degrees in Audiology from Syracuse University. She is Professor and Chair in Communication Sciences and Disorders. with secondary faculty appointments in Linguistics and Otolaryngology-Head and Neck Surgery. Dr. Souza's research interests include speech recognition, hearing aids, and the effects of aging and cognitive change on communication. A recurring theme in her scientific work is understanding individual auditory and cognitive abilities in order to customize hearing treatment. Dr. Souza is a Fellow of the Acoustical Society of America, the American Speech-Language-Hearing Association, and the Knowles Hearing Center. She is a licensed audiologist with experience in a variety of medical settings. Her clinical interests include hearing aids, severe hearing loss, hearing assistive technology, tinnitus management, and patient education. Dr. Souza's research is funded by the National Institutes on Deafness and Communication Disorders and by the Knowles Hearing Center.

Xiaodong Tan, PhD

Assistant Professor, Otolaryngology-Head and Neck Surgery

Bio

I develop and improve auditory protection and restoration strategies for individuals experiencing hearing loss due to chemotherapy, noise exposure, generic alterations, and aging. My passion for this field stems from witnessing the profound yet often underestimated impact of hearing loss on individuals and their families, driving me to find innovative solutions to mitigate these challenges.

My career has been marked by research in auditory function, hearing protection, and hearing. I have investigated signal processing in the central auditory system, studied the structural and functional evolution of prestin, a protein essential for cochlear amplification, and been involved in the development of a novel laser-based cochlear implant. These experiences, spanning neuroscience, physiology, molecular biology, and bioengineering, have shaped my understanding of auditory science.

A pivotal moment in my career was discovering from a cancer research peer that honokiol, a plant-extracted multifunctional molecule that improves mitochondrial function, holds promise for cancer treatment. I immediately recognized its potential for hearing protection during chemotherapy. To explore this, I collaborated with multiple laboratories at Northwestern and other institutes specializing in cancer biology, physiology, and molecular biology of hearing.

Looking ahead, I aspire to further my research in hearing protection and restoration, hoping to develop more effective interventions for hearing loss. My dream is to see these advancements widely implemented, ultimately improving the lives of millions affected by hearing impairment.

Donna S Whitlon, PhD

Research Professor, Otolaryngology - Head and Neck Surgery

Bio

I lived in Florida when I was a child and was completely enamored with the space program. When I was 16, a science project and later my Congressman earned me VIP trips to the launches of Apollo 11 and Apollo 13. In tours of the NASA space center facility, I was eager to learn everything, and I found myself loving the idea of many people working together, collaborating on ideas, generating ways to do new science. It set me on my path to becoming a scientist myself.

My goal now is to discover drugs for hearing loss. I am a biochemist, but I started out in the auditory field by studying the anatomy and proteins in the axons (processes) of cochlear spiral ganglion neurons during development. I started to study the neurons and their axons in the culture dish - to try to get the axons to grow, and to try to find drugs that would make damaged axons grow longer. This led to animal studies and finally to a clinical trial on sudden hearing loss.

The beauty of the mammalian cochlea under the microscope, the potential to learn something new at any time, and the goal of drug discovery, is what has been the driving force every day of my career.

I find myself surrounded by some of the most creative, thoughtful, critical scientists who do wonderful work and also collaborate generously, thus following my initial dream of working together to generate new science. Communication is crucial in life, in relationships, and in health. I would like my work to be important in helping to find a simple new way to treat hearing loss and I want it to be valuable to those young people in the military who are often exposed to high level noise, to those with hearing impairment due to trauma, in aging, and those who experience sudden hearing loss.

Tracy Winn, PhD

Assistant Clinical Professor, Communication Sciences and Disorders

Bio

I am a licensed clinical audiologist and preceptor for the Doctor of Audiology students at the Northwestern University Center for Audiology, Speech, Language, and Learning. I provide diagnostic and treatment services for hearing loss.

I provide these services for adult and pediatric patients. I also evaluate adults and children for auditory processing disorders. In addition to providing clinical services to the community, I supervise and teach clinical service provision for the students in our Au.D. program.

Beverly Wright, PhD

Professor

Bio

Beverly Wright and her students explore the general principles of auditory learning, a process that leads to dramatic improvements in perceptual skills. The lab seeks to identify the circumstances that are necessary for learning to occur as well as those that disrupt learning. These principles are examined using stimuli ranging from simple sounds to speech, and tasks ranging from fine-grained discrimination to categorization and intelligibility. For example, the lab has demonstrated that exposure to an acoustic stimulus can facilitate learning on a perceptual task, but only when that exposure occurs within ~30 minutes of practice on that task.
Although the lab's research program focuses on normal adults, it also pursues how learning changes with age, sensory experience (hearing loss), and cognitive background (e.g., language and reading disorders). One proposal currently under study with a learning paradigm is that individuals with reading disorders often perform poorly on auditory perceptual tasks because their perceptual development is delayed in childhood and then halted during adolescence. Thus, research on perceptual learning may lead to more effective training strategies for those with perceptual disorders and may be used as objective, clinical measures to guide diagnosis and treatment of cognitive disorders.

Nancy M Young, MD

Lillian S Wells Professor of Pediatric Otolaryngology, Pediatric Otology & Neurotology

Bio

I am a physician, surgeon, and researcher passionate about children's hearing and language. My current research uses pre-surgical brain imaging and AI-enabled analytical methods to predict language on the individual child level. The long-term goal of this project is custom brain-based therapy to maximize children's language.

My grandfather was a silent film editor. My father, an engineer, received Academy Awards for technical contributions to the film industry. I grew up attending film festivals. Why did I become interested in hearing loss? The answer came years later when a previously unknown cousin told me his story. He was initially thought to have intellectual disability but was later diagnosed with hearing loss as a teen. Hearing aids gave him spoken language.

I began my career after a neurotology fellowship when there were few women surgeons. I was charged with creating a cochlear implant program. I performed the first implant surgery on a child in Chicago. Since then, I have performed over 2,000 cochlear implant surgeries. Our team is composed of 21 multidisciplinary members and is one of the largest in the world. I also am the tenth women Fellow of the American Otologic Society, the second oldest US medical society.

Early in my career I became convinced that neuroplasticity and early, effective intervention is essential to improving outcomes. This led to my current research using pre-surgical brain imaging and AI-enabled analytical methods to predict language on the individual child level.

Kevin Zhan

Assistant Professor, Otolaryngology - Head and Neck Surgery

Bio

My clinical and research focus is to tackle the significant underutilization of cochlear implantation in the US and increase access to hearing care in all forms.

I think it's an incredible privilege to be able to help patients hear better. Our ability to hear one another and communicate is so much of what makes us human. Yet, as a society, we tend to minimize hearing loss across the age spectrum and stigmatize hearing devices.

I am an ear and lateral skull base surgeon at Northwestern Medicine and an assistant professor of otolaryngology – head & neck surgery. I hope to train our next generation of ENT surgeons, physicians, and audiologists on the enormous value of treating hearing loss and expanding access to hearing care, regardless of where their careers may lead.

I am honored to be the director of the Northwestern Medicine Cochlear Implant program, a wonderful multidisciplinary and collaborative team of hearing healthcare clinicians and scientists all working in tandem to improve hearing care in the Chicagoland area.

Jing Zheng

Associate Professor, Dept of Otolaryngology-Head and Neck Surgery

Bio

Our work is dedicated to gaining new knowledge and understanding of hearing and hearing loss. One of the most pressing issues in our field is the inability to identify cochlear stress before irreversible tissue damage and hearing loss occur. This underscores the importance of exploring cochlear stress biomarkers, a topic of great interest for researchers and clinicians.

As an Asian immigrant woman, I have overcome challenges faced by women minorities, progressing from a foreign graduate student in Michigan to an associate professor at Northwestern.

Hearing loss is a life-altering condition caused by various factors such as noise, age, and ototoxic drugs. Mammalian hearing relies on outer hair cells (OHCs) to amplify sound signals mechanically for high sensitivity and sharp frequency selectivity. In our lab, we study proteins essential for hearing. OHCs are one of the most vulnerable cells in the inner ear and a major contributor to sensorineural hearing loss.

Our research on OHCs aim to provide crucial insights into the pathology of cochlear damage and pave the way for more effective diagnostic and therapeutic interventions.