Baylor University Researcher Completes Sabbatical at Largest Auditory Research Center in Europe
Hannover, Germany is home to one of the top research schools for implantable medical devices in the world—Hannover Medical School—and within the school resides Deutsches HörZentrum Hannover, the largest auditory research center in Europe. There, Baylor University’s Department of Communication Sciences and Disorders researcher Yang-Soo Yoon, PhD, Associate Professor, had an opportunity to spend a semester abroad to expand upon his research in improving speech perception in noise.
Binaural hearing, or the ability to perceive sound in both ears, is critical for the brain to fully interpret auditory inputs for speech perception in background noise and locations of sound sources in complex listening environments. Unfortunately, hearing loss—in individuals of all ages—is quite common. These individuals are often prescribed hearing aids or cochlear implants to help improve the auditory acoustics critical for auditory perception and sound localization. Yoon’s lab is investigating several technology scenarios, as hearing aids and cochlear implants work differently but can work together in different combinations.
Bimodal hearing combines the benefits of a hearing aid placed in one ear and a cochlear implant in the opposite ear, allowing for binaural hearing. In addition, Yoon is studying Electric Acoustic Stimulation (EAS), which is the use of these two devices together in the same ear, allowing for monaural hearing. Through this combination, the hearing aid amplifies low-frequency sounds, and the cochlear implant electrically stimulates the middle to high-frequency sounds. Yoon’s team is striving to understand the underlying mechanisms of how peripheral and central auditory systems communicate in order to integrate two different streams of signals across ears (for example, bimodal hearing) and within ear (for example, EAS).
“My current research, which is supported by the NIH, focuses on understanding how the auditory system integrates two different streams of auditory inputs: acoustic input processed by a hearing aid and electric input processed by a cochlear implant,” he said. “Current clinical practices, which are not standardized, for fitting bimodal and EAS patients result in large variability in speech perception. Our long-term goal is to develop an individually optimized fitting procedure for bimodal and EAS users.”
Yoon’s research sabbatical at the internationally renowned Deutsches HörZentrum Hannover allowed for a collaboration with the Auditory Prosthetic Group, led by Dr. Waldo Nogueira.
“The primary research areas of the Auditory Prosthetic Group are perfectly aligned with my research program for bimodal and EAS hearing using signal processing, auditory modeling, and psychoacoustics. Our lab focuses on measuring human behavioral perceptions by manipulating key variables, while the German group focuses on measuring brain activities using an electroencephalogram,” he explained. “Human perception is a result of a series of brain activities, but it does not tell us the internal details of the cortical activities. By combining the behavioral and electrophysiological approaches, we can provide a methodological framework to investigate the underlying mechanisms of how the auditory system integrates acoustic and electric stimulations.”
While in Hannover, Yoon also had the opportunity to share his knowledge with the international research community. He presented at the International Conference on Biomedical Technology in Hannover and at the Hearing4All International Symposium in Oldenburg. Also, he was invited to share new concepts for restoring hearing loss at the University Hospital of Zurich’s Otolaryngology Department.
In addition to research, Yoon took time to explore Germany’s architecture, culture, rich history and well-established traditions. These opportunities provided an unexpected, renewed sense of inspiration for his research. He enjoyed visiting small towns (Dresden was a standout) and the beautiful Christmas markets. He found abundant opportunities to learn more about classical composers (like Bach, Beethoven, Brahms, Handel), mathematicians and scientists (such as Gauss, Einstein, and Leibniz), philosophers (such as Nietzsche, Kant, Hegel, and Marx), and writers (like Goethe, Thomas Mann, and Herman Hesse).
“Stopping by Albert Einstein’s student locker at Federal Institute of Technology at Zurich inspired me to be better scientist,” he said. “Doing research in a new place allowed me to connect my own incomplete knowledge with real, historical sites and facts about these individuals, extending my world view.”
Yoon recently returned to Baylor’s campus where he continues research on improving speech perception by optimizing combined acoustic and electric auditory information. He regards the collaboration with the Auditory Prosthetic Group, conference presentations, and travel through Europe was, and will continue to be, a substantial experience.