Understanding speech in background noise is a common, yet effortful task that involves interactive auditory and cognitive processes. Age-related declines in the neural systems that underlie these functions may explain why speech-in-noise recognition is especially difficult for older adults, even for those with little to no hearing loss. This project will design, implement, and test interventions that train top-down, executive functions within an auditory task in order to improve speech recognition in noise for older normal-hearing adults. The current proposal systematically tests the overarching hypothesis that speech recognition in noise can be improved via training that specifically targets the interactive neural systems that underlie changes in auditory-cognitive processing with age. Three sets of experiments will identify patterns of cortical activity that 1) are associated with age-related changes in speech recognition in noise, 2) are engaged with candidate training exercises, and 3) that change with auditory-cognitive training. Behavioral, neural (using magnetoencephalography, MEG), and pupil dilation measures will be obtained in healthy younger and older adults with normal hearing. Specifically, Aim 1 tests the hypothesis that age-related declines in speech recognition in noise are predicted by changes in top-down modulation of auditory cortex activity. The proposed study will examine the extent to which age- related changes in the neural representation of speech in auditory cortex are associated with poorer speech recognition and greater cognitive effort.
Aim 1 also tests whether these age-related declines are associated with a weaker relationship between frontal and temporal cortex activity.
Aim 2 evaluates the extent to which specific auditory-cognitive tasks elicit top-down modulation of auditory cortex activity. Tasks that place greater demands on domain-general executive functions (e.g., inhibitory control, working memory) in the context of an auditory processing task are predicted to more robustly modulate frontal-temporal connectivity.
Aim 3 tests the extent to which changes in top-down modulation of temporal cortex activity following auditory-cognitive training predict improvements in speech recognition in noise. In contrast to previous studies that have employed passive control groups, Aim 3 will test the prediction that an integrated auditory-cognitive training program yields increased frontal-temporal connectivity and thus better speech recognition in noise and reduced listening effort compared to an active training control group. By increasing our understanding of the aging brain, we aim to develop effective interventions to improve speech recognition and the overall quality of life of older adults.
