The Speech Perception Puzzle Jonathan Venezia seeks to understand why people—even those with normal or near-normal peripheral hearing—have difficulty processing speech. Foundational Questions
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Foundational Questions  |   June 01, 2018
The Speech Perception Puzzle
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Hearing & Speech Perception / Foundational Questions
Foundational Questions   |   June 01, 2018
The Speech Perception Puzzle
The ASHA Leader, June 2018, Vol. 23, online only. doi:10.1044/leader.FQ.23062018.np
The ASHA Leader, June 2018, Vol. 23, online only. doi:10.1044/leader.FQ.23062018.np
Name: Jonathan H. Venezia, PhD, Research Scientist, VA Loma Linda Healthcare System; Research Assistant Professor, Department of Otolaryngology, Loma Linda University
ASHFoundation funding: 2015 New Investigators Research Grant
What is the focus of your research?
The broad goal of my research program is to improve the diagnosis and treatment of people who have difficulty processing speech, including those with sensorineural hearing loss, aphasia and combat-related blast exposure.
Two related branches of research build toward this overall goal. The first focuses on describing the basic perceptual and neural mechanisms involved in extracting meaningful information from human speech. Different types of meaningful information—such as linguistic content, emotional tone or talker identity—all have unique acoustic signatures. I develop and evaluate new psychoacoustic procedures to identify these acoustic signatures in terms of human perception—and, using noninvasive electrophysiological and neuroimaging techniques, measure how and where different speech-acoustic signatures are processed in the central auditory nervous system.
The second branch focuses on understanding the auditory mechanisms that contribute to functional communication deficits in auditory-related disorders. By using the techniques developed in the first branch, I measure how perceptual and neural representations of speech and other related sounds become disrupted by bottom-up (sensorineural hearing loss), top-down (aphasia) or composite (blast exposure) changes in auditory processing.
How did your award from the ASHFoundation lead to your current work?
As a postdoctoral fellow in 2015, I received an ASHFoundation New Investigators Research Grant. I was developing a psychoacoustic technique to “map” the acoustic patterns that enable good speech recognition in quiet. This technique, which I call “auditory bubbles,” removes randomly selected acoustic patterns from speech and measures the relation between different patterns and speech-recognition performance. It generates a perceptual map linking acoustic patterns to behavior.
With my ASHFoundation grant, I studied how these maps change in listeners with sensorineural hearing loss. I then refined “auditory bubbles” and applied the technique to map other phenomena, including perception of emotional tone from speech and recognition of a target talker in the presence of a competing talker. I also adapted the technique to functional magnetic resonance imaging (fMRI) to measure “neural maps” of speech in different regions of the human auditory cortex.
These projects served as pilot data for a now-funded VA Career Development Award-2 proposal. A major aim of this research is to use “auditory bubbles” to study how aging and combat-related blast exposure affect perceptual and neural maps of speech generated in a competing-talker scenario.
What do you hope to demonstrate through your research—or what has it already demonstrated?
Real-world speech perception relies on a complex interplay among auditory, cognitive and language systems at multiple levels of processing. The brain mechanisms underlying this interplay are not well understood—even for healthy listeners—making it difficult to identify the source of speech perception deficits in people with auditory, cognitive and/or linguistic processing difficulties. Techniques like “auditory bubbles” allow us to visualize internal speech representations at the interface between multiple brain systems, providing a window into how real-world speech processing is carried out in healthy listeners and listeners with functional communication deficits.
For example, my recent fMRI work shows that acoustic patterns related to different speech information (for example, phonemes and syllables versus words and phrases, or vocal pitch versus phonetic content) is processed in different auditory cortex subsystems. So now we can ask whether different disorders affect particular subsystems, whether the effects depend on attention, or how processing multiple talkers taxes the different subsystems.
Why did you choose this particular research focus?
Speech and language are uniquely human capacities that have the potential to reveal the fundamental nature of the human mind and brain—a strong draw from a scientific perspective. The real-world application is especially relevant in the context of my position as a VA researcher, as auditory-related disorders outnumber all other service-connected disabilities among veterans, with annual compensation and treatment costs topping $1 billion. Many veterans, particularly those with blast exposure, report speech perception difficulties despite normal or near-normal peripheral hearing. I was drawn to the mysterious nature of this deficit, and felt my approach to investigating high-level aspects of speech perception was well-suited to the problem. I am grateful for the opportunity to apply my techniques to serve veterans.
How has ASHFoundation funding affected your professional life?
ASHFoundation funding completely transformed my professional life. When I received my award in 2015, I had not yet applied for major research funding, nor had I received extramural funding from another source. My ASHFoundation project set me firmly on the path of scientific inquiry that led to my successful application for a major VA research award.
Moreover, the ASHFoundation award allowed me to apply for the ASHA Lessons for Success grant-writing workshop, which I attended in 2016 prior to applying for VA funding. That workshop was an amazing opportunity to learn about grant-writing mechanics, receive career advice from established scientists, and network with other young scientists in all areas of hearing, speech and language science. This year, I will return to the workshop to talk about my experiences—successes and hardships—in applying for research funding and launching a career as a principal investigator. I strongly recommend that other junior-level scientists and professionals take advantage of the funding and career development opportunities offered by ASHA and the ASHFoundation.
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June 2018
Volume 23, Issue 6