Thesis (Ph.D.)--Syracuse University, 2008. / "Publication number: AAT 3333580."

Thesis (Ph. D.)--University of Toronto, 2008. / Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 114-119.

Thesis (M.A.)--University of Wisconsin--Madison, 1973. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

<p> Several studies across various languages have shown that monolingual listeners perceive significant differences between the speech of monolinguals and bilinguals. However, these differences may not always affect the phoneme category as identified by the listener or the speaker; differences may often be found between tokens corresponding to unique phonological categories and, as such, be more easily detectable through acoustic analysis. We hypothesized that unshared English vowels produced by young Spanish-English bilinguals would have measurably different formant values and duration than the same vowels produced by young English monolinguals because of Spanish influence on English phonology. We did not find significant differences in formant values between the two groups, but we found that SpanishEnglish bilinguals produced certain vowels with longer duration than English monolinguals. Our findings add to the ever-growing body of literature on bilingual language acquisition and the perception of accentedness.</p><p>

The purpose of this project was to differentially examine the specificity of two acoustic measures, relative fundamental frequency (RFF) and the cepstral/spectral index of dysphonia (CSID), to listener perceptions of voice quality across four dimensions: breathiness, roughness, strain/vocal effort, and overall severity. An auditory perceptual experiment was conducted to estimate listener perception of said dimensions. The Pearson's correlation coefficient between RFF, CSID, and the perceptual ratings of voice quality was calculated in order to comment on the relationship between calculations of RFF and CSID and the current "gold standard" of listener perception. The hypothesis for this project was that measures of RFF would have a strong negative correlation with listener perception of strain/vocal effort, and that measures of CSID would have a strong positive correlation with listener perception of overall severity and breathiness. An unexpected result with a significant impact was found to be that listeners' ratings of the four voice qualities were highly correlated with one another. Unfortunately, the poorly differentiated perceptual ratings significantly impact the validity of this project in addition to hindering any reliability of its results. Thus overall, the correlations between measures of RFF, CSID, and distinct qualities of listener perception are rendered uninterpretable. Methodological considerations and future directions are henceforth reported.

Repeated exposure to disparity between the motor plan and auditory feedback during speech production results in a proportionate change in the motor system’s response known as auditory-motor adaptation. Artificially raising F1 in auditory feedback during speech production results in a concomitant decrease in F1. Transcranial direct current stimulation (tDCS) can be used to alter neuronal excitability in focal areas of the brain. The present experiment explored the effect of noninvasive brain stimulation applied to the speech premotor cortex on the timing and magnitude of adaptation responses to artificially raised F1 in auditory feedback. Participants (N=16) completed a speaking task in which they read target words aloud. Participants' speech was processed to raise F1 by 30% and played back to them over headphones in real time. A within-subjects design compared acoustics of participants’ speech while receiving anodal (active) tDCS stimulation versus sham (control) stimulation. Participants' speech showed an increasing magnitude of adaptation of F1 over time during anodal stimulation compared to sham. These results indicate that tDCS can affect behavioral response during auditory-motor adaptation, which may have translational implications for sensorimotor training in speech disorders.

The present study examines the efficacy of group conversation intervention for Individuals with Severe Aphasia (IWSA) in a preliminary case study of five participants. IWSA are particularly marginalized from society as a result of profound communication deficits. Current efficacious treatment strategies for IWSA are compensatory in nature however, IWSA have the same goals of less severe profiles with regard to rengagement in social and community life. IWSA are commonly excluded from research regarding participation based treatment due to their complex profiles. Aims of the study were to determine if IWSA improved in discrete linguistic measures, functional and quality of life measures and targeted elements of discourse production as a result of 20 total hours of group conversation therapy. Results of evaluations conducted at pre-treatment, post-treatment and maintenance intervals revealed significant improvements on standardized linguistic measures from pre to post treatment for two of the five participants. Group analysis of functional measures showed no change across testing intervals, however when individual clinically significant change scores were calculated on one measure, three of five participants demonstrated clinically significant increase in self-reported communicative effectiveness at maintenance testing. Results of discourse analysis were variable by participant and dependent on targeted outcome measures/individualized goals. Overall, results should be interpreted with caution, due to the variability in the participant’s profiles, lack of a standard measurement tool for narrative samples and small sample size. Patterns in results prompt further research regarding efficacy of conversation therapy for IWSA.