Matching Items (4)
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- All Subjects: Speech therapy
- All Subjects: Articulation disorders
- 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
Distorted vowel production is a hallmark characteristic of dysarthric speech, irrespective of the underlying neurological condition or dysarthria diagnosis. A variety of acoustic metrics have been used to study the nature of vowel production deficits in dysarthria; however, not all demonstrate sensitivity to the exhibited deficits. Less attention has been paid to quantifying the vowel production deficits associated with the specific dysarthrias. Attempts to characterize the relationship between naturally degraded vowel production in dysarthria with overall intelligibility have met with mixed results, leading some to question the nature of this relationship. It has been suggested that aberrant vowel acoustics may be an index of overall severity of the impairment and not an "integral component" of the intelligibility deficit. A limitation of previous work detailing perceptual consequences of disordered vowel acoustics is that overall intelligibility, not vowel identification accuracy, has been the perceptual measure of interest. A series of three experiments were conducted to address the problems outlined herein. The goals of the first experiment were to identify subsets of vowel metrics that reliably distinguish speakers with dysarthria from non-disordered speakers and differentiate the dysarthria subtypes. Vowel metrics that capture vowel centralization and reduced spectral distinctiveness among vowels differentiated dysarthric from non-disordered speakers. Vowel metrics generally failed to differentiate speakers according to their dysarthria diagnosis. The second and third experiments were conducted to evaluate the relationship between degraded vowel acoustics and the resulting percept. In the second experiment, correlation and regression analyses revealed vowel metrics that capture vowel centralization and distinctiveness and movement of the second formant frequency were most predictive of vowel identification accuracy and overall intelligibility. The third experiment was conducted to evaluate the extent to which the nature of the acoustic degradation predicts the resulting percept. Results suggest distinctive vowel tokens are better identified and, likewise, better-identified tokens are more distinctive. Further, an above-chance level agreement between nature of vowel misclassification and misidentification errors was demonstrated for all vowels, suggesting degraded vowel acoustics are not merely an index of severity in dysarthria, but rather are an integral component of the resultant intelligibility disorder.
ContributorsLansford, Kaitlin L (Author) / Liss, Julie M (Thesis advisor) / Dorman, Michael F. (Committee member) / Azuma, Tamiko (Committee member) / Lotto, Andrew J (Committee member) / Arizona State University (Publisher)
Created2012
Description
Purpose: The present study examined grammatical gender use in child Spanish heritage speakers (HSs) in order to determine whether the differences observed in their grammar, when compared to Spanish monolinguals, stem from an incompletely acquired grammar, in which development stops, or from a restructuring process, in which features from the dominant and the weaker language converge to form a new grammatical system. In addition, this study evaluated whether the differences usually found in comprehension are also present in production. Finally, this study evaluates if HSs differences are the result of the input available to them.
Method: One-hundred and four typically developing children, 48 HSs and 58 monolingual, were selected based on two age groups (Preschool vs. 3rd Grade). Two comprehension and three production experimental tasks were designed for the three different grammatical structures where Spanish expresses gender (determiners, adjectives, and clitic pronouns). Linear mixed-models were used to examine main effects between groups and grammatical structures.
Results: Results from this study showed that HSs scored significantly lower than monolingual speakers in all tasks and structures; however, 3rd-Grade HSs had higher accuracy than PK-HSs. Error patterns were similar between monolinguals and HSs. Moreover, the commonly reported overgeneralization of the masculine form seems to decrease as HSs get older.
Conclusion: These results suggest that HSs’ do not face a case of Incomplete Acquisition or Restructured Grammatical gender system, but instead follow a protracted language development in which grammatical skills continue to develop after preschool years and follow the same developmental patterns as monolingual children
Method: One-hundred and four typically developing children, 48 HSs and 58 monolingual, were selected based on two age groups (Preschool vs. 3rd Grade). Two comprehension and three production experimental tasks were designed for the three different grammatical structures where Spanish expresses gender (determiners, adjectives, and clitic pronouns). Linear mixed-models were used to examine main effects between groups and grammatical structures.
Results: Results from this study showed that HSs scored significantly lower than monolingual speakers in all tasks and structures; however, 3rd-Grade HSs had higher accuracy than PK-HSs. Error patterns were similar between monolinguals and HSs. Moreover, the commonly reported overgeneralization of the masculine form seems to decrease as HSs get older.
Conclusion: These results suggest that HSs’ do not face a case of Incomplete Acquisition or Restructured Grammatical gender system, but instead follow a protracted language development in which grammatical skills continue to develop after preschool years and follow the same developmental patterns as monolingual children
ContributorsMartinez-Nieto, Lourdes (Author) / Restrepo, Maria Adelaida (Thesis advisor) / Renaud, Claire (Thesis advisor) / Pascual y Cabo, Diego (Committee member) / Thompson, Marilyn (Committee member) / Ingram, David (Committee member) / Arizona State University (Publisher)
Created2018
Description
A substantial amount of research demonstrates that preschoolers' phonological awareness skills are a robust predictor of children's later decoding ability. Several investigators examined performance of children with speech sound impairment (SSI), defined as inaccurate production of speech sounds in the absence of any etiology or communication impairment, on phonological awareness tasks. Investigators found that children with SSI scored below their typically developing peers (TD) on phonological awareness tasks. In contrast, others found no differences between groups. It seems likely that differences in findings regarding phonological awareness skills among children with SSI is the fact that there is considerable heterogeneity among children with SSI (i.e., speech errors can either be a phonological or articulation). Phonology is one component of a child's language system and a phonological impairment (SSI-PI) is evident when patterns of deviations of speech sounds are exhibited in a language system. Children with an articulation impairment (SSI-AI) produce speech sound errors that are affected by the movements of the articulators, not sound patterns. The purpose of the study was to examine whether or not children with SSI-PI are at greater risk for acquiring phonological awareness skills than children with SSI-AI. Furthermore, the phonological awareness skills of children with SSI-PI and SSI-AI were compared to those of their typical peers. In addition, the role of executive function as well as the influence of phonological working memory on phonological awareness task performance was examined.
Findings indicate that the SSI-PI group performed more poorly on an assessment of phonological awareness skills than the SSI-AI and TD groups. The SSI-PI group performed significantly more poorly on tasks of executive function and phonological working memory than the TD group. The results of this study support the hypothesis that children with SSI-PI may be more vulnerable to difficulties in reading than children with SSI-AI and children with TD.
Findings indicate that the SSI-PI group performed more poorly on an assessment of phonological awareness skills than the SSI-AI and TD groups. The SSI-PI group performed significantly more poorly on tasks of executive function and phonological working memory than the TD group. The results of this study support the hypothesis that children with SSI-PI may be more vulnerable to difficulties in reading than children with SSI-AI and children with TD.
ContributorsFox, Angela Marie (Author) / Wilcox, M. Jeanne (Thesis advisor) / Ingram, David (Committee member) / Gray, Shelley (Committee member) / Connor, Carol (Committee member) / Arizona State University (Publisher)
Created2015