Jiang, Jessica;
(2023)
Perception of degraded speech in primary progressive aphasia and Alzheimer's disease.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Accurate and flexible understanding of speech in daily life depends critically on our brains’ capacity to respond efficiently and adaptively to diverse auditory inputs in multiple contexts and environments. As major dementias strike the brain’s auditory and language processing networks relatively selectively, early, and saliently, comprehension of speech under challenging listening conditions is a significant clinical issue in neurodegenerative diseases, particularly Alzheimer’s disease (AD) and primary progressive aphasia (PPA). In this thesis, I designed new measures to probe and assess degraded speech perception in AD and PPA, in comparison to healthy older listeners. I investigated how both verbal and nonverbal signals associated with speech are affected in these diseases under degraded listening conditions (simulating those that occur in everyday life) and delineated ‘phenotypes’ of degraded speech processing accompanying particular diseases. In Chapter 3, I used phonemic restoration to simulate everyday listening conditions where speech signals are interrupted by background noises. In Chapter 4 and 5, I used noise-vocoding to simulate listening scenarios where verbal and nonverbal emotional signals are of suboptimal quality. In Chapter 6, I used sinewave-transformed accents to assess whether paralinguistic features can convey nonverbal semantic information about speakers even in highly degraded acoustic environments. After taking account of peripheral hearing and general cognitive limitations, AD and PPA syndromes had distinct and separable profiles of impairment across experiments. My findings have implications for understanding the association between hearing impairment and cognitive decline, and for the design of novel diagnostic tests, markers, and interventions addressing real-world communication in major dementias.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Perception of degraded speech in primary progressive aphasia and Alzheimer's disease |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Neurodegenerative Diseases |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10167253 |
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