Older adults, even those with relatively normal hearing, have trouble recognizing speech in background
noise. Consequently, older adults often have difficulty engaging in normal conversations and therefore
experience a diminished quality of life. In order to adequately remedy such communication impairments, we
need to understand factors beyond the peripheral auditory system that impact communication in older adults.
In particular, inhibitory control, the ability to suppress irrelevant information, may help the listener ignore
background noise and facilitate identification of a target word by inhibiting similar-sounding but inappropriate
alternatives. The goal of this project is to better understand the role of inhibitory control in speech recognition
by 1) delineating the neural mechanisms that support speech recognition in noise for older adults with varying
inhibitory control abilities and 2) driving the inhibitory control system to assess its direct impact on moment-to-
moment word recognition. This project will inform the rehabilitation of communication in the aging adult
population by investigating how inhibitory control contributes to understanding speech in noise.
This proposal aims to determine how the availability and moment-to-moment recruitment of inhibitory
control affects speech recognition in noise among older adults. Stimulus competition will be used to induce
inhibitory control in older adults with high versus low inhibitory control in order to characterize the support of
neural systems for speech recognition on a subsequent trial using fMRI. Using the phenomenon of conflict
adaptation, wherein competing information leads to the recruitment of inhibitory control and boosts
performance on subsequent trials, this project will determine the extent to which experiencing audiovisual
conflict increases correct word identification. Moreover, by comparing performance and neural activity in adults
with high versus low inhibitory control, this study will investigate the extent to which reduced inhibitory control
contributes to age-related declines in speech comprehension.
The results of this research will advance our understanding of how inhibitory control supports speech
recognition in older adults. The results are expected to identify novel methods to enhance communication and
identify individuals who will most benefit from treatments for hearing loss and who may require inhibitory
control training as an intervention to improve speech comprehension.