The speech of an individual conveys a great deal of information about how their central nervous system (CNS) is performing. Whether they are tired, distressed or suffering from a degenerative disease affecting the brainstem, speech can change as a function of an individual’s condition. Yet, when assessing the speech in an individual on the first occasion, it is often difficult to determine whether their performance is different from a pre-morbid level. Therefore, the repeated acquisition and analysis of a set of brief and simple speech measures could provide information on changes in a patient’s performance over time. This could ultimately lead to the inclusion of objective markers of change in trials of conditions and disorders that currently rely of subjective, clinician derived measures of severity or patient self report, such as pain, depression or fatigue. Furthermore, the information could be used to track patient performance in treatment trials for degenerative disorders, such as Friedreich ataxia or Huntington’s disease. / This thesis aimed to evaluate the practical, experimental and statistical requirements of speech assessment protocols designed to monitor patient performance over time. The research involved a number of studies evaluating methods for acquiring and analysing data, studies examining the stability and sensitivity of speech stimuli, and finally, the functionality of these findings in an experimental model known to induce change in CNS function (i.e., sustained wakefulness). / Methods for acquiring and analysing speech data were designed to provide a balance between the concurrent demands for precision and useability inherent in repeated assessment protocols. Data from these studies provided evidence that techniques offering high levels of useability (e.g., easy to use, automated) are capable of offering adequate precision on broad acoustic measures of timing and frequency. Moreover, these methods could be standardised and automated, allowing non-expert users to collect and analyse data in a controlled and time efficient manner. The second series of experiments systematically documented the stability and responsiveness of speech stimuli within a variety of experimental conditions. These studies were designed to establish the suitability of select speech measures for monitoring change in individuals over time, as stimuli that proved to be both stable (across several re-test intervals) and sensitive to change or impairment were ideal candidates. Finally, a proof of concept study designed to evaluate the efficiency and sensitivity of the proposed methodology was initiated in an experimental model known to induce changes in psychomotor functioning in healthy adults (sustained wakefulness). Significant changes from baseline were observed in speech production as a function of increasing levels of fatigue. These findings are important as they demonstrate the potential of speech as a valid, reliable and sensitive marker of change in conditions where the CNS is subject to stress.
| Identifer | oai:union.ndltd.org:ADTP/282045 |
| Date | January 2010 |
| Creators | Vogel, Adam P. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
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