Project Summary/Abstract Age-related hearing loss (ARHL) affects a large number of older adults (~50% of adults aged 75+), yet not all individuals are equally impacted. Understanding why some older adults struggle more with ARHL is an important first step in designing more effective treatment plans. This proposal explores the hypothesis that individual differences in the use of contextual vs. acoustic-phonetic cues explains variation in speech comprehension abilities beyond just hearing ability. Natural listening environments contain a variety of cues that listeners can rely on to aid in speech comprehension. Despite the availability of many cues, recent work with healthy younger adults and older adults (including pilot work for this proposal) has demonstrated that some individuals tend to rely more on higher-level contextual information and others rely more on lower-level acoustic-phonetic information to interpret ambiguities in speech. The goal of this project is to test the hypothesis that these individual patterns of cue use will explain differences in speech comprehension (Aim 1) and to examine at what point in processing these individual differences arise using neural data collected from electroencephalography (EEG; Aim 2). One two-session experiment will be run testing younger and older adults on an audiometry battery, a cognitive battery, a cue use task in which they listen to sentences that contain ambiguous words, and a passive storybook listening task. EEG will be recorded during the cue use task and the storybook listening. While controlling for hearing and cognitive abilities, the contribution of an individual’s cue use will be tested in a model predicting speech comprehension (Aim 1). Neural data will then be analyzed to test three potential mechanisms that could lead to behavioral differences in cue use: (1) differences in early perceptual encoding of ambiguities in speech, (2) differences in later repair processes, and (3) differences in overall predictive mechanisms. A combination of event-related potential (ERP) and temporal response function (TRF) analyses will be performed to identify the locus of individual differences. Overall, this proposal provides important insight into different profiles of ARHL, and insights from neural data will highlight where in processing differences arise, potentially serving as a basis for designing effective treatments. Additionally, studying patterns of cue use may potentially reveal individuals whose ARHL may initially go undetected (those who tend to rely more on contextual cues). This proposal will prepare the applicant to lead an independent line of work examining the neurobiology of speech comprehension from an individual differences lens. Specifically, this proposal will give the applicant opportunities to engage with clinicians, expand individual differences work in cue use into older adults, and gain expertise in multiple computationally intensive analysis methods of EEG data.