Identifying the ‘Why’ of Hearing Loss Tiffany Johnson’s ASHFoundation-supported research aims to help audiologists pinpoint the cause of a person’s hearing loss. Foundational Questions
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Foundational Questions  |   December 01, 2018
Identifying the ‘Why’ of Hearing Loss
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Hearing Disorders / ASHA News & Member Stories / Foundational Questions
Foundational Questions   |   December 01, 2018
Identifying the ‘Why’ of Hearing Loss
The ASHA Leader, December 2018, Vol. 23, online only. doi:10.1044/leader.FQ.23122018.np
The ASHA Leader, December 2018, Vol. 23, online only. doi:10.1044/leader.FQ.23122018.np
Name: Tiffany A. Johnson, PhD, CCC-A, Associate Professor, Department of Hearing and Speech, University of Kansas Medical Center
ASHFoundation Award: 2008 Clinical Research Grant ($50,000), “New Directions in Clinical Applications of Otoacoustic Emissions”
What is the focus of your research?
Research in my lab focuses on improving the diagnostic techniques available to audiologists. I am particularly interested in developing tools to identify pathology that may be missed by our current techniques.
How did your award from the ASHFoundation lead to your current work?
The long-term goal of the ASHFoundation-supported work was to improve the accuracy with which otoacoustic emissions (OAEs) distinguish ears with mild hearing loss from ears with normal hearing—a distinction that is difficult and leads to screening errors. In completing the ASHFoundation-sponsored work and subsequent work, we learned a lot about how stimulus manipulations, guided by knowledge of cochlear processing, influence the accuracy with which OAEs identify hearing loss. We also learned a lot about the limits of what we could do to improve test accuracy through these manipulations. This line of research suggested we could improve OAE test accuracy for selected people, but not in a way that would improve accuracy in the general population.
Although that was a disappointing outcome, it got us thinking differently about potential sources of errors in OAE screening tests. In particular, we began to think more about the limitations of the pure-tone audiogram. At about the same time, the evidence related to hidden hearing loss and cochlear synaptopathy in animal models was increasing. Exploring the possibility that hidden hearing loss exists in normal-hearing, noise-exposed human ears was a natural extension of our growing interest in identifying pathology that isn’t present in the pure-tone audiogram. Current projects in the lab are related to noise exposure and hidden hearing loss, but can be traced back to our original interests in identifying mild (and subtle) hearing loss.
What do you hope to demonstrate through your research—or what has it already demonstrated?
We aim to develop tools that audiologists can use to more precisely specify the nature of pathology underlying hearing loss and difficulties with speech perception. Our current focus is on demonstrating whether or not hidden hearing loss exists in human ears. In the last several years, various labs have reported conflicting evidence related to the existence of hidden hearing loss in humans. We’ve seen evidence both for and against this pathology in data from our lab, and have consistently seen differences in males and females that are surprising. More specifically, data from females are consistent with results we would expect in hidden hearing loss, while data from males are not—and are often opposite of what would be expected. We continue to work on this problem.
Why did you choose this particular research focus?
I chose to work on developing new diagnostic tools because my original interest in the field of audiology and hearing science started when I learned that our ears are capable of producing sound—otoacoustic emissions. My original fascination with OAEs expanded to other non-invasive physiologic techniques for quantifying auditory function. To improve outcomes and treatments for children and adults with hearing loss, I firmly believe that we need better tools for diagnosing the nature of the pathology.
How has ASHFoundation funding affected your professional life?
Many programs supported by the ASHFoundation—Lessons for Success, grant opportunities, grant review and reviewer training—were critical to my success as a junior faculty member. The programs helped set me on a path toward research success and helped me achieve tenure—a necessary step for a career in higher education.
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FROM THIS ISSUE
December 2018
Volume 23, Issue 12