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- All Subjects: Problems of Projection
- Creators: Ingram, David
Description
Often termed the "gold standard" in the differential diagnosis of dysarthria, the etiology-based Mayo Clinic classification approach has been used nearly exclusively by clinicians since the early 1970s. However, the current descriptive method results in a distinct overlap of perceptual features across various etiologies, thus limiting the clinical utility of such a system for differential diagnosis. Acoustic analysis may provide a more objective measure for improvement in overall reliability (Guerra & Lovely, 2003) of classification. The following paper investigates the potential use of a taxonomical approach to dysarthria. The purpose of this study was to identify a set of acoustic correlates of perceptual dimensions used to group similarly sounding speakers with dysarthria, irrespective of disease etiology. The present study utilized a free classification auditory perceptual task in order to identify a set of salient speech characteristics displayed by speakers with varying dysarthria types and perceived by listeners, which was then analyzed using multidimensional scaling (MDS), correlation analysis, and cluster analysis. In addition, discriminant function analysis (DFA) was conducted to establish the feasibility of using the dimensions underlying perceptual similarity in dysarthria to classify speakers into both listener-derived clusters and etiology-based categories. The following hypothesis was identified: Because of the presumed predictive link between the acoustic correlates and listener-derived clusters, the DFA classification results should resemble the perceptual clusters more closely than the etiology-based (Mayo System) classifications. Results of the present investigation's MDS revealed three dimensions, which were significantly correlated with 1) metrics capturing rate and rhythm, 2) intelligibility, and 3) all of the long-term average spectrum metrics in the 8000 Hz band, which has been linked to degree of phonemic distinctiveness (Utianski et al., February 2012). A qualitative examination of listener notes supported the MDS and correlation results, with listeners overwhelmingly making reference to speaking rate/rhythm, intelligibility, and articulatory precision while participating in the free classification task. Additionally, acoustic correlates revealed by the MDS and subjected to DFA indeed predicted listener group classification. These results beget acoustic measurement as representative of listener perception, and represent the first phase in supporting the use of a perceptually relevant taxonomy of dysarthria.
ContributorsNorton, Rebecca (Author) / Liss, Julie (Thesis advisor) / Azuma, Tamiko (Committee member) / Ingram, David (Committee member) / Arizona State University (Publisher)
Created2012
Description
This dissertation draws upon modern Chomskyan theory to address issues surrounding the development of a unified, minimalist account of language as a mental and biological object, both in terms of its generation and historic change. Towards that end, I investigate, apply, and advance the labeling approach to generative syntax. Labeling is a hypothetical process, operating within the confines of phase theory, which is thought to prepare constructed syntactic objects for interpretation at relevant mental interfaces. I argue a number of points applicable to both synchronic and diachronic linguistics: 1) Labeling failures happen as a matter of course during a derivation, forcing re-evaluation of labeled syntactic structures which ultimately leads to a successful derivation. 2) Labeling and its errors do not happen in real-time, but are bounded by phases. This has consequences for how researchers ought to look at notions and limitations of phasal memory. 3) Labeling not only drives an individual’s mature syntax, but has an effect on how children acquire their syntax, causing them in some cases to alter structures and create new categories. This is responsible for many cases of language change, and I support this argument by investigating data from the history of Chinese and Macedonian that are sensitive to labeling-based phenomena. 4) Research into labeling can help us speculate about the evolution of language generally. Although recursion is sometimes thought to be a defining feature of Universal Grammar, labeling in fact is a much more likely candidate in this regard.
ContributorsSanatana-LaBarge, Robert E. (Author) / Gelderen, Elly van (Thesis advisor) / Ingram, David (Committee member) / Piattelli-Palmarini, Massimo (Committee member) / Arizona State University (Publisher)
Created2016