James Dewey, Ph.D.

Meet the Researcher

Dewey received his doctorate in communication sciences and disorders from Northwestern University in Illinois. He has since been a postdoctoral research associate, first in the otolaryngology-head & neck surgery department at Stanford University, California, and now at the University of Southern California. Dewey is a 2020 Emerging Research Grants recipient, and was renewed for a second year in 2023.

I have long been interested in how the ear emits sounds and what these sounds tell us about the inner workings of the cochlea. I first studied these sounds, termed otoacoustic emissions (OAEs), in human ears during my doctoral work, when it became clear that there are many fascinating, unexplained patterns in the measurements. I’ve since learned how to measure vibrations of the structures within the cochlea in animal models, and now I am finally in a position to trace (in mice) the path of OAEs from where they are generated in the cochlea out to the ear canal.

Both my mother and brother are scientists and professors but I was initially more interested in the arts. In the end, being a scientist is somewhat like being an artist. There is a lot of uncertainty, creativity, and decision-making involved; you have to convince others to fund your work, and your output is routinely criticized and refined. I aim to share research results in an aesthetically pleasing, easy-to-understand way.

I have a mild high-frequency hearing loss, likely from listening to loud live music with little or no hearing protection. I changed my ways after starting a clinical doctorate program in audiology, where I was able to both routinely test my hearing and learn about the permanent physiological impacts from noise exposure.

Camping in the deserts of Southern California plays a role in helping to clarify my science. While the desert may seem empty, there is an amazing level of detail and diversity in each micro-environment, and there are always unexpected turns in weather or encounters with wildlife. Afterward, I find it easier to make progress in connecting scientific ideas, writing, and planning the next experiments.

I often record interesting acoustic events I encounter when I travel or even just during my daily routine, such as running down a sand dune or a blizzard outside my window. I enjoy going back to these recordings, some dating back two decades now, much like looking at old photo albums.

I hope to continue unraveling the mystery of how the cochlea works. As we learn more about what noninvasive, objective measurements can tell us about cochlear physiology in animal models, the hope is to ultimately translate these findings into ways to better detect, characterize, and prevent hearing loss in humans.

James Dewey, Ph.D., is funded by donors to Hearing Health Foundation who designated their gifts for the most promising research. HHF thanks our community for supporting projects that address the full range of hearing and balance science.

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The Research

University of Southern California
Filtering of otoacoustic emissions: a window onto cochlear frequency tuning

Healthy ears emit sounds that can be measured in the ear canal with a sensitive microphone. These otoacoustic emissions (OAEs) offer a noninvasive window onto the mechanical processes within the cochlea that confer typical hearing, and are commonly measured in the clinic to detect hearing loss. Nevertheless, their interpretation remains limited by uncertainties regarding how they are generated within the cochlea and how they propagate out of it. Through experiments in mice, this project will test theoretical relationships that suggest that OAEs are strongly shaped (or “filtered”) as they travel through the cochlea, and that this filtering is related to how well the ear can discriminate sounds at different frequencies. This may lead to novel, noninvasive tests of human cochlear function, and specifically frequency discrimination, which is important for understanding speech.

Long-term goal: To understand the mechanical amplification processes within the cochlea that provide typical hearing, and to develop objective, noninvasive tests of cochlear hair cell function for the early detection, differential diagnosis, and prevention of hearing loss.