Quantitative relationships were established between speech intelligibility and gaze patterns when subjects listened to sentences spoken by a single talker at different auditory SNRs while viewing one or more talkers. When the auditory SNR was reduced and subjects moved their eyes freely, the main gaze strategy involved looking closer to the mouth. The natural tendency to move closer to the mouth was found to be consistent with a gaze strategy that helps subjects improve their speech intelligibility in environments that include multiple talkers. With a single talker and a fixed point of gaze, subjects' speech intelligibility was found to be optimal for fixations that were distributed within 10 degrees of the center of the mouth. Lower performance was observed at larger eccentricities, and this decrease in performance was investigated by mapping the reduced acuity in the peripheral region to various levels of spatial degradation.

published_or_final_version / Speech and Hearing Sciences / Master / Master of Science in Audiology

published_or_final_version / toc / Speech and Hearing Sciences / Master / Master of Science in Audiology

Dysarthria is one of the most common signs of speech impairment in the cerebral palsy (CP) population. Facilitating strategies for speech enhancement in this population often include training on speech breathing. Treatment efficacy studies with cross-system measures in this population are needed for improved understanding and management of the interrelationship between respiratory, phonatory, and articulatory systems. The purpose of this study was to investigate the effect of breath group control on the coordination of articulatory and phonatory muscles and the acoustic measures related to speech and voice quality. A simultaneous acoustic, electroglottographic (EGG), and marker-based facial tracking recording system was employed to monitor the speech production behaviors of four adults with CP and 16 neurologically healthy controls. Subjects were instructed to perform three tasks, each containing speech targets with a voiceless plosive (/p/, /t/, or /k/) preceding a vowel (/i/, /a/, /u/, or /ɔ/). Task 1 consisted of a short reading passage embedded with target vowels without cueing from breath group markers. Task 2 included reading a series of monosyllabic and 3-syllable or 5-syllable non-speech words with the speech targets. Task 3 included reading the same short passage from Task 1 with cueing from breath group markers separating the passage into phrases with no more than five syllables per phrase. Measures from the acoustic, EGG and facial tracking recordings of the first and last syllable of all syllable trains produced in the non-speech task and the target vowels in the passage reading task were examined. Acoustic measures included voice onset time (VOT), vowel duration, fundamental frequency (F0), percent jitter (%jitter), percent shimmer (%shimmer), signal-to-noise ratio (SNR), and frequencies of Formants one and two (F1 and F2). EGG measures included speed quotient (SQ) and open quotient (OQ). Facial tracking measures consisted of maximum jaw displacement. Individual and averaged data were submitted to a series of two-way Analysis of Variances (ANOVAs) or two-way Repeated Measures ANOVAs to determine the effects of the relative position of an utterance in the breath group and the place of articulation of the consonants involved. In addition, mean vowel spaces derived from all three tasks were examined. Results revealed significant changes of VOT, F1, F2, SNR and SQ as a function of position. Significant changes of VOT, vowel duration, F2, F0, %jitter, %shimmer, and maximum jaw displacement as a function of place of articulation were also evident. In particular, breath group control was found to result in expansion of vowel space, especially for individuals with CP. These findings suggest that proper phrasing enhances articulatory and phonatory stability, providing empirical evidences in support of its usage in treating individuals with CP.

Thesis (M.S.)--Rochester Institute of Technology, 1990. / Includes bibliographical references (leaves 41-42).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 102-104).

Thesis (B.Sc)--University of Hong Kong, 2002. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, May 10, 2002." Also available in print.

Thesis (Ph.D.)--University of Florida, 2005. / Typescript. Title from title page of source document. Document formatted into pages; contains 84 pages. Includes Vita. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 183-200).

A new objective measurement system to predict speech intelligibility in binaural listening conditions is proposed for use with nonlinear hearing devices. Digital processing inside such devices often involves nonlinear operations such as clipping, compression, and noise reduction algorithms. Standard objective measures such as the Articulation Indeix (AI), the Speech Intelligibility Index (SII) and the Speech Transmission Index (STI) have been developed for monaural listening. Binaural extensions of these measures have been proposed in the literature, essentially consisting of a binaural pre-processing stage followed by monaural intelligibility prediction using the better ear or the binaurally enhanced signal. In this work, a three-stage extension of the binaural SII approach is proposed that deals with nonlinear acoustic input signals. The reference-based model operates as follows: (1) a stage to deal with nonlinear processing based on a signal-separation model to recover estimates of speech, noise and distortion signals at the output of hearing devices; (2) a binaural processing stage using the Equalization-Cancellation (EC) model; and (3) a stage for intelligibility prediction using the SII or the short-time Extended SII (ESII). Multiple versions of the model have been developed and tested for use with hearing devices. A software simulator is used to perform hearing-device processing under various binaural listening conditions. Details of the modeling procedure are discussed along with an experimental framework for collecting subjective intelligibility data. In the absence of hearing-device processing, the model successfully predicts speech intelligibility in all spatial configurations considered. Varying levels of success were obtained using two simple distortion modeling approaches with different distortion mechanisms. Future refinements to the model are proposed based on the results discussed in this work.