PROJECT SUMMARY/ABSTRACT
The goal of this research is to address the critical barriers to communication that older and hearing-impaired
listeners face in complex acoustic scenes, in which multiple competing sounds impede speech understanding.
Our approach includes simultaneous behavioral and electrophysiological measures of auditory stream
segregation, and importantly, we also determine the costs and benefits of hearing instruments on segregating
multiple speech sources. Our research has uncovered neural mechanisms associated with age-related
declines in auditory temporal processing that play a critical role in binaural and spatial hearing. Our current
tools, however, lack the precision necessary to gain deeper understanding of this age-related deficit. In the
present study, we propose a series of innovative approaches that aim to determine the functional boundaries
of spatial hearing in listeners with age-related hearing loss (ARHL). In Aim 1, we use a well-established
paradigm of auditory scene analysis to define functional, ecologically relevant boundaries of perception as they
relate to individual binaural cues, and measure how these boundaries are affected by ARHL at the neural level.
Aim 2 introduces novel behavioral and electrophysiological tasks that precisely measure functional boundaries
between segregation and integration of competing speech. Aim 3 evaluates the costs and benefits of
directional microphone technology to hearing-impaired listeners as a function of their individual spatial
segregation boundaries. The present study draws from a long line of research on auditory scene analysis and
introduces a novel approach to cortical tracking of speech envelope in complex scenes. This project pushes
the field forward in how we measure mechanisms of stream segregation in older and hearing-impaired
listeners. The results of these experiments will: (1) precisely characterize individual binaural and spatial
segregation boundaries; (2) provide evidence of the neural circuitry and patterns of activity underlying the
influence of spatial cues on stream segregation; (3) discover evidence for the relationship between binaural
segregation boundaries, individual differences, and the effects of hearing loss and aging; and (4) investigate a
relationship between individual suprathreshold hearing abilities and specific hearing aid processing technology.
Whereas hearing devices currently have remarkable benefits to specific users, the present research should
inspire a new push for innovative ways to address hearing challenges of an aging population. Our team is well-
positioned to execute behavioral and electrophysiological measures sensitive to auditory function and
intervention outcomes, and critically, to bridge these to shift the field toward individualized hearing health care.