Thesis (Ph. D.)--University of Chicago, Dept. of Linguistics, Aug. 2003. / Includes bibliographical references (p. 178-186). Also available on the Internet.

Thesis (Ph.D.)--University of Melbourne, Dept. of Electrical and Electronic Engineering and Dept. of Otolaryngology, and the Bionic Ear Institute, 2009. / Typescript. Includes bibliographical references.

Thesis (M. Aud.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 66-68).

Thesis (B.Sc)--University of Hong Kong, 2007. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2007." Includes bibliographical references (p. 27-30). Also available in print.

Cochlear implants have successfully been used to enable hundreds of thousands of profoundly deaf people to regain some perception of hearing. Hearing performance does, however, vary greatly among individual implant users. In order to gain a better understanding of the underlying factors that cause these inter-user performance differences, insight into the functioning of individual implant users’ hearing systems is required. Some of the parameters unique to an implanted user’s hearing system may be measured non-invasively using psychoacoustics or the measurement of electrically evoked compound action potentials. While these methods provide information of the macro response of a user’s hearing system to stimulation, individual parameters, for example the individual neurons that are excited cannot be measured. Some individual parameters are difficult or even impossible to measure in a living human as it is not technically feasible or invasive surgery is required. When obtaining measurements inside the inner ear of a living human is not an option, an alternative that mimics the human hearing system is required from which measurements can be predicted: models. This study describes the development of a method to construct an electrical computational three-dimensional finite element model of the implanted cochlea of a specific living individual. This method is presented as a tool for researchers to probe the cochleae of specific implanted users non-invasively. Data from a low resolution computer tomography scan is used to construct a geometric representation of the bony outer cochlear structures and augmented with histologic data to construct the smaller inner cochlear structures. A detailed skull geometry with brain and scalp volumes that includes the user’s return electrode is also constructed. The user’s electrode array is modelled in its intra-cochlear location and stimulation is simulated using finite element modelling. The cochleae of five individual ears were modelled and intra-cochlear and neural node potentials were predicted along with neural excitation patterns. Having models that can predict user-specific outcomes, predictions that include the variability between implanted ears are obtained. This allowed the comparison of modelled data to common trends found in literature and enabled the investigation of questions frequently asked by modellers. These include the effect that bone resistivity, head volume shape, return electrode implementation and return electrode position have on modelled results. These findings were incorporated and contributed to higher detailed models being produced than are currently described in literature. The models were then practically applied in two areas. The first was in the quantification of potential decay in the cochlea where a simple model is derived to predict decay at the neuron level based on the location of an electrode. The second was in the translation of the model into the clinical domain where the mismatch between the perceived pitch and mapped frequencies of specific implanted individuals were predicted. Along with these predictions it was found that neural excitation and intra-cochlear potential spread are highly dependent on individual cochlear morphology. This warrants the inclusion of user-specific morphology in volume conduction models of the implanted cochlea where user-specific outcomes are predicted. / Thesis (PhD (Electronic Engineering))--University of Pretoria, 2015. / Electrical, Electronic and Computer Engineering / PhD (Electronic Engineering) / Unrestricted

Most previous research into cochlear implant (CI) mediated music listening deals with the mechanisms and efficacy of music perception and does not often account for the listeners real-world musical experience. Measurements of music perception ability are based on listening tasks such as pitch-discrimination, timbre-recognition and rhythmic-identification, and rarely (if ever) relate to the individual experience of the human subject. The exploration of musical experience, however, is based on a holistic view of the ways in which individual people experience music, which can be informed by the interaction of a multitude of factors. For the purposes of this thesis, three categories of experience are considered to coalesce to inform the general musical experience: sensory experience, cognitive experience and social/environmental experience. This thesis moves towards consideration of the real-world musical experiences of cochlear implant users (CIUs) with a view of developing strategies that can be implemented to improve those elements of the musical experience that may be problematic. The thesis comprises three main sections as follows: The first section investigates the musical experiences of CI users (CIUs) by means of a questionnaire study and the consideration of information gained from music focus groups and conversations with implant users. Results show a great deal of variability in the musical experiences of CIUs but many people report positive experiences of music despite suffering from what may be described as ‘poor’ music perception. The second section outlines the design, development and implementation of a multi-channel mixer application, which is used in a study exploring the way in which CIUs mix multi-channel music, to gain insight into their experience of musical elements. Analysing the user-generated mix data provides considerable insights into various elements of the musical experience of participants. Again, results show a large degree of variability on this issue amongst CIUs, and also that the average mixes of CIUs differ significantly from that of a control group of normal-hearing (NH) participants. The third section describes the composition, development and evaluation of a musical work specifically composed for CIUs but designed to be enjoyable for both CIUs and NH audience members alike. The aim of this composition is to promote a positive musical experience by addressing elements of the sensory, cognitive and social/environmental experience based on findings of this research. This thesis concludes by suggesting that the ideal approach for improving the musical experiences of CIUs should focus on the individual, due to the great deal of variability within this population, and presents some implications of this work and suggestions for future research in this area.

Thesis (M. Sc. in Audiology)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 31-35).

Thesis (M. Aud.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 106-120). Also available via the World Wide Web.

Thesis (M.A.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (leaves 98-102).

Thesis (M. Communication Pathology)--University of Pretoria, 2004. / Includes bibliographical references.