No description available.

The cochlea presumably possesses a number of regulatory mechanisms to maintain cochlear sensitivity in the face of disturbances to its function. Evidence for such mechanisms can be found in the time-course of the recovery of CAP thresholds during experimental manipulations, and in observations of slow oscillations in cochlear micromechanics following exposure to low-frequency tones (the “bounce phenomenon”) and other perturbations. To increase our understanding of the these oscillatory processes within the cochlea, and OHCs in particular, investigations into cochlear regulation were carried out using a combination of mathematical modelling of the ionic and mechanical interactions likely to exist within the OHCs, and electrophysiological experiments conducted in guinea pigs. The electrophysiological experiments consisted of electrocochleographic recordings and, in some cases, measurement of otoacoustic emissions, during a variety of experimental perturbations, including the application of force to the cochlear wall, exposure to very-low-frequency tones, injection of direct current into scala tympani, and intracochlear perfusions of artificial perilymph containing altered concentrations of potassium, sodium, and sucrose. To obtain a panoramic view of cochlear regulation under these conditions, software was written to enable the interleaved and near-simultaneous measurement of multiple indicators of cochlear function, including the compound action potential (CAP) threshold, amplitude and waveshape at multiple frequencies, the OHC transfer curves derived from low-frequency cochlear microphonic (CM) waveforms, distortion-product otoacoustic emissions (DPOAEs), the spectrum of the round-window neural noise (SNN), and the endocochlear potential (EP). The mathematical model takes into account the known electrical properties of OHC, and includes the effect of fast and slow-motility of the cell body on transducer operating point and apical conductance. Central to the operation of the model is a putative intracellular 2nd-messenger system based on cytosolic calcium, which is involved in regulation of i) the operating point of OHC MET channels via slow motility and axial stiffness; ii) the permeability of the basolateral wall to potassium (via calcium-sensitive potassium channels); and iii) the cytosolic concentration of calcium itself, via modulation of its own sequestration into (and release from) intracellular storage organelles, and extrusion from the cell. The model was constructed in a manner which allowed simulation of different cochlear perturbations, and the comparison of results from these simulations to experimental data. The mathematical model we have developed provided a physiologically-plausible and internally-consistent explanation for the time-courses of the cochlear changes observed during a number of different perturbations. We show that much of the oscillatory behaviour within the cochlea is consistent with underlying oscillations in cytosolic calcium concentration. We conclude that a number of the discrepancies between the simulation results and the experimental data can be resolved if the cytosolic calcium functions as two distinct pools: one which controls basolateral permeability and one which controls slow motility. This two-calcium-pool model is discussed. / Thesis presented in partial fulfilment of the requirements of the degree of Master of Clinical Audiology / Doctor of Philosophy of The University of Western Australia

The ability to identify where sound is coming from is required for everyday listening tasks such as identifying in which direction the phone is ringing and to help locate who is calling your name in a social situation. While this localization ability has been found to be reduced in listeners with a hearing loss in the typically measured frequency range of 250 to 8000 kHz, less is known about listeners who have a hearing loss that is mainly limited to the extended high frequencies of 8 to 14 kHz, particularly when abilities are tested with speech stimuli. The purpose of the current study was to determine whether listeners with a hearing impairment at these higher frequencies performed less accurately in a number of localization tasks. Twenty-three participants with normal hearing (thresholds not exceeding 20 dB HL from 250 to 14 kHz) and 23 participants with normal hearing up to and including 3 kHz and with at least a moderate hearing loss in the extended high frequencies (thresholds reaching at least 55 dB HL in any of the frequencies from 8 kHz to 14 kHz), localized noise and speech stimuli at a level of 75 dBA in a free field situation. Thirteen speakers were used in four different speaker arrangements; the frontal horizontal plane, lateral horizontal plane, frontal vertical plane and lateral vertical plane. The noise stimuli included noise band-passed filtered between 300 Hz and 16 kHz, and 300 Hz and 8 kHz. Speech stimuli were individual words with strong amounts of high frequency content above 8 kHz and weak amounts of high frequency content above 8 kHz. The two types of speech stimuli were also band-passed filtered using the same filter cut-off frequencies as the noise stimuli. No significant main effect differences were found between the localization ability of the two hearing groups for any of the four experiments. However, within experiment analysis revealed in the lateral vertical plane the normal hearing group localized significantly better than the hearing loss group for both the strong and weak stimuli. Significant differences were also found across experiments with both groups of participants localizing more accurately in the frontal horizontal plane and worst in the frontal vertical plane. All participants were found to localize significantly better with the greater bandwidth of 300 Hz to 16 kHz, and also for both types of speech stimuli when compared to the noise stimuli, although post hoc analysis found that these differences were not consistent between all speaker locations.

My research question arose from my first therapeutic experience with a client who hears voices. I felt unprepared and uncertain about how to work with her. I wondered how other therapists experienced working with clients who hear voices. These are voices heard with no physical origin, experienced as real and which psychiatry typically describes as hallucinations. This research provides an empirical account of the individual lived experiences of seven therapists undertaking such work using an interpretative phenomenological analysis. These seven participants were recruited using snowballing emails and included four counsellors, a psychotherapist, a nurse therapist and a counselling psychologist working in various settings. The literature points to which therapeutic approaches are most useful and identifies an important role for Counselling Psychology. There is no research which explores the experience of therapists working with clients who hear voices or what it is like for them to work with such clients. The main body of the research literature focuses on what it means for people to hear voices and how therapists can help them cope. I was interested in the impact this has on the therapist and the therapeutic relationship and what the unique aspects of this work might be. The analysis gave rise to six superordinate themes which were; 'Questioning their competence', 'Relational experience of the work', 'Struggles and difficulties', 'Sense of reality and the unknown', 'Surviving and coping' and Characteristics of client and voices'. These themes are explored in the findings section and discussed in relationship to the extant literature. In gaining this phenomenological perspective this research offers an insight into some of the difficulties of work with this client group. These insights propose a useful contribution towards continuing professional development training courses, initial training programmes, guidelines for supervision and understanding of the impact on therapeutic practice.

No description available.

The phenomenon of auditory hallucinations in clinical populations of non-psychotic children is an intriguing and little understood area. To date, investigations in this area have reported on a range of correlates, including family histories of psychiatric illness, family dysfunction, and significant levels of stress in the children themselves. The current study reported on 10 non-psychotic children drawn from a number of community based child and family agencies that provide therapeutic out-patient services. Consistent with previous studies this study found strong associations with family dysfunction, specifically family break-up, as well as significant levels of anxiety and depression in the these children. In addition, half the children reported the presence of imaginary companions. Despite some confirmation of previous findings, many other features of this phenomenon remain unanswered including the different psychological functions that hallucinations and imaginary companions serve for emotionally troubled children. Two case studies describe the family histories and hallucinations in more detail. / Thesis (MPsy(Clinical))--University of South Australia, 2006.

The phenomenon of auditory hallucinations in clinical populations of non-psychotic children is an intriguing and little understood area. To date, investigations in this area have reported on a range of correlates, including family histories of psychiatric illness, family dysfunction, and significant levels of stress in the children themselves. The current study reported on 10 non-psychotic children drawn from a number of community based child and family agencies that provide therapeutic out-patient services. Consistent with previous studies this study found strong associations with family dysfunction, specifically family break-up, as well as significant levels of anxiety and depression in the these children. In addition, half the children reported the presence of imaginary companions. Despite some confirmation of previous findings, many other features of this phenomenon remain unanswered including the different psychological functions that hallucinations and imaginary companions serve for emotionally troubled children. Two case studies describe the family histories and hallucinations in more detail. / Thesis (MPsy(Clinical))--University of South Australia, 2006.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 139-143).

Thesis (B.Sc.)--University of Hong Kong, 2003. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, April 30, 2003." Includes bibliographical references (p. 28-30) Also available in print.