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.
This research will elucidate the role of inhibitory control in speech recognition in older adults, thereby increasing our understanding of the neural mechanisms underlying the perception and comprehension of language and the impact of aging on this system. This research will advance our understanding of how to enhance communication for older adults with and without clinically significant hearing loss through the engagement of neural systems that implement inhibitory control.
