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dc.contributor.authorWayne, Rachel
dc.contributor.otherQueen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.))en
dc.description.abstractSpeech perception routinely takes place in noisy or degraded listening environments, leading to ambiguity in the identity of the speech token. Here, I present one review paper and two experimental papers that highlight cognitive and visual speech contributions to the listening process, particularly in challenging listening environments. First, I survey the literature linking audiometric age-related hearing loss and cognitive decline and review the four proposed causal mechanisms underlying this link. I argue that future research in this area requires greater consideration of the functional overlap between hearing and cognition. I also present an alternative framework for understanding causal relationships between age-related declines in hearing and cognition, with emphasis on the interconnected nature of hearing and cognition and likely contributions from multiple causal mechanisms. I also provide a number of testable hypotheses to examine how impairments in one domain may affect the other. In my first experimental study, I examine the direct contribution of working memory (through a cognitive training manipulation) on speech in noise comprehension in older adults. My results challenge the efficacy of cognitive training more generally, and also provide support for the contribution of sentence context in reducing working memory load. My findings also challenge the ubiquitous use of the Reading Span test as a pure test of working memory. In a second experimental (fMRI) study, I examine the role of attention in audiovisual speech integration, particularly when the acoustic signal is degraded. I demonstrate that attentional processes support audiovisual speech integration in the middle and superior temporal gyri, as well as the fusiform gyrus. My results also suggest that the superior temporal sulcus is sensitive to intelligibility enhancement, regardless of how this benefit is obtained (i.e., whether it is obtained through visual speech information or speech clarity). In addition, I also demonstrate that both the cingulo-opercular network and motor speech areas are recruited in difficult listening conditions. Taken together, these findings augment our understanding of cognitive contributions to the listening process and demonstrate that memory, working memory, and executive control networks may flexibly be recruited in order to meet listening demands in challenging environments.en_US
dc.relation.ispartofseriesCanadian thesesen
dc.rightsAttribution-NonCommercial-NoDerivs 3.0 United States*
dc.rightsQueen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canadaen
dc.rightsProQuest PhD and Master's Theses International Dissemination Agreementen
dc.rightsIntellectual Property Guidelines at Queen's Universityen
dc.rightsCopying and Preserving Your Thesisen
dc.rightsThis publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.en
dc.subjectSpeech perceptionen_US
dc.subjectCognitive trainingen_US
dc.subjectWorking memoryen_US
dc.subjectCognitive agingen_US
dc.subjectHearing impairmenten_US
dc.subjectSpeech communicationen_US
dc.subjectSpeech in noiseen_US
dc.subjectCognitive hearing scienceen_US
dc.subjectReading span testen_US
dc.subjectSuperior temporal gyrusen_US
dc.subjectFusiform face areaen_US
dc.subjectAudiovisual speech integrationen_US
dc.subjectAuditory agingen_US
dc.subjectCingulo-opercular networken_US
dc.subjectNoise-vocoded speechen_US
dc.subjectDegraded speechen_US
dc.subjectAge-related hearing lossen_US
dc.titleCognitive and Visual Speech Contributions to Speech Perception in Challenging Listening Conditionsen_US
dc.description.degreeDoctor of Philosophyen_US
dc.contributor.supervisorJohnsrude, Ingrid S.en

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