SPUR 2021: Hearing in Noisy Backgrounds

Background

Although current hearing devices improve listening in quiet environments, they do little to improve speech understanding in noisy backgrounds. The long-term goal of this research program is to fully understand the relationship between auditory perception and physiological mechanisms responsible for adapting to the local soundscape. The objective of this particular application is to understand the role of the medial olivocochlear (MOC) reflex in the perception of fluctuating sounds and on speech-in-noise performance in normal hearing and hearing impaired listeners using perceptual, electrophysiological, and auditory modeling techniques. The central hypothesis of the proposed research is that cochlear hearing loss limits the ability of the MOC reflex to regulate cochlear gain, thus preventing the putative perceptual and neural benefits associated with the reflex. The rationale of the proposed research is that a detailed description of the influence of the MOC reflex on human auditory function has the potential to translate to a better understanding of why hearing devices provide little benefit to improving speech-in-noise performance in hearing impaired adults. This detailed description will be obtained by completing the following specific aims: 1) Determine the role of the MOC reflex in the detection of temporal fluctuations and the identification of speech syllables in noise; 2) Determine the effect of eliciting the ipsilateral MOC reflex on the compound action potential (CAP) in human subjects with and without cochlear hearing loss; and 3) Simulate the influence of the MOC reflex on auditory function in listeners with and without cochlear hearing loss.

Student Role

Student research assistants will participate in the design, execution, analysis, and publication of research. Primarily responsibilities will include running and documenting data collection sessions, summarizing data collected in table and figures, summarizing research findings in reports written to the lab manager, and reviewing/discussing pertinent literature on the project. Data collection for evoked potentials experiments will involve measuring electrical potentials from the brain and the cochlea in human participants via passive electrodes placed on the high-forehead and eardrum. Data collection for perceptual experiments will involve working with a customized graphical user interface in Matlab to quantify the sensitivity of human participants to specific features of sound.

Student Learning Outcomes & Benefits

At the completion of this research experience, the student will:

  • understand neural mechanisms underlying auditory perception
  • understand the anatomy and physiology of auditory reflexes
  • understand principles of auditory evoked responses
  • understand how to measure and quantify auditory perception
  • master techniques for measuring auditory evoked potentials
  • master techniques for measuring auditory perception
  • gain or improve on a working knowledge of Matlab programming
  • gain or improve on the analysis of electrical and acoustic signals in time and frequency domains
  • deepen skills on critically evaluating research

Remote Contingency Plan

An arm of my research involves predicting human perception and physiology using a computational model of the auditory system based on neurophysiological studies in laboratory animals. Simulations are conducted remotely through resources at the Center for High Performance Computing (CHPC). I have a backlog of model simulations that need to be completed. After my Summer 2020 SPUR project was cancelled, the Office of Undergraduate Research offered me the opportunity to work with an undergraduate student through UROP, provided that I could engage the student in a high-quality remote research experience. The UROP student and I worked remotely on model simulations over the summer and have continued our collaboration this Fall. Recently, [the UROP student] was invited to present his work at a Zoom meeting with experts in auditory models. Our success shows that a student can be easily shifted from the primary project to a modeling project when face-to-face mentoring is not possible. The student can access CHPC resources and run the model simulations from a computer web browser. In addition to running the simulations remotely, I have found that consistent virtual meetings, an electronic notebook (through LabArchives), and directed readings result in a quality research experience for the student despite the inability to meet face-to-face. If the proposed research is not possible, my contingency plan is to reassign the SPUR 2021 student to a model simulation project.

Skyler Jennings
Associate Professor

Communication Sciences & Disorders
College of Health

Neuroscience Program

My teaching philosophy is summarized in three statements:

  1. be a chef, not a cook!
  2. understand the graphs, and
  3. rise to the challenge.

Be a chef, not a cook!: I found the major difference between student “chefs” and “cooks” is the ability to master concepts rather than master facts. I teach concepts in hearing science by packaging them into a model or framework. I introduce and develop these models through examples, figures, drawings, formulas, and succinct summary statements.

Understand the graphs: Data is at the heart of the concepts and models in hearing science. Analyzing a graph is an essential skill for learning new ideas and refining the models and frameworks that drive research.

Rise to the challenge: I believe the rigor and quality of an education is substantially increased when instructors facilitate in depth learning and “raise the bar” on academic performance in these areas. My experience is that students will rise to the instructor’s expectations if the appropriate support structure is in place. I challenge students with advanced topics in acoustic impedance, signals and systems, Fourier analysis, cochlear physiology, models of the auditory periphery, and psychophysical models of auditory perception. I support students with these challenges by carefully designing assignments, being responsive to email and face-to-face communication, and facilitating interaction with other research assistants.

Students in my lab benefit from mentoring activities such as: guided literature reviews, impromptu whiteboard discussions, mini-teaching / discussion session during lab meetings, and brainstorming sessions about research and how to improve the lab where students are full and valued participants.