Thesis (M.S.)--Brigham Young University. Dept. of Audiology and Speech-Language Pathology, 2005. / Includes bibliographical references (leaves 37-41).

A novel technology, the Magneto-articulography for the Assessment of Speech Kinematics (MASK) system, which measures brain activity and oromotor movement simultaneously, was validated for its speech tracking capabilities. MASK has not been systematically tested, so its movement tracking accuracy and practicality for research was still unknown. An error testing and mapping protocol is developed to validate MASK accuracy against established electromagnetic articulography (EMA) speech tracking systems. Data from human speech experiments are also compared. MASK exhibited higher positional error and fluctuation than EMA, and more inconsistent distribution of errors. Error mapping and potential error correction protocols were also developed. MASK spatial and temporal resolutions were found insufficient for precise tracking of small and quick articulatory movements. MASK requires much improvement to reach the capabilities of EMA. Further investigation into numerical instabilities of the position calculation algorithms is encouraged. This project provides the first assessment of MASK, which may advance speech research for future applications.

A novel technology, the Magneto-articulography for the Assessment of Speech Kinematics (MASK) system, which measures brain activity and oromotor movement simultaneously, was validated for its speech tracking capabilities. MASK has not been systematically tested, so its movement tracking accuracy and practicality for research was still unknown. An error testing and mapping protocol is developed to validate MASK accuracy against established electromagnetic articulography (EMA) speech tracking systems. Data from human speech experiments are also compared. MASK exhibited higher positional error and fluctuation than EMA, and more inconsistent distribution of errors. Error mapping and potential error correction protocols were also developed. MASK spatial and temporal resolutions were found insufficient for precise tracking of small and quick articulatory movements. MASK requires much improvement to reach the capabilities of EMA. Further investigation into numerical instabilities of the position calculation algorithms is encouraged. This project provides the first assessment of MASK, which may advance speech research for future applications.

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.

The purpose of this study was to compare the effects on speech acoustics of a wide variety of speaking instructions that have been used across different studies on clear speech, and to investigate the acoustic and articulatory changes that occur in response to these instructions and in different talking environments. Five young adult females were recorded speaking under different instructions meant to elicit more intelligible speech, and measures of speaking rate, speaking F0 and intensity were found to distinguish instructions to speak "as if to someone with hearing loss" from instructions to speak "clearly" or "slowly", which produced different results from instructions to speak "loudly" or as if in noise. Preliminary acoustic and articulatory data are described for a sixth talker who spoke under a subset of these instructions, and in both a quiet and a noisy talking environment.

This study examined kinematic and acoustic adaptation following the placement of electromagnetic articulography (EMA) sensors, which measure speech articulator movements. Sixteen typical native English speakers had eight EMA sensors attached to obtain kinematic data: three to the tongue (front, mid, and back at midline), one on the lower incisors (jaw), two on the lips (one on each lip at midline), and two reference sensors on the eyeglass frames worn by the participants. They repeated the same sentence stimuli 5 times every two minutes (0, 2, 4, 6 minutes post-attachment) while both acoustic and kinematic data were recorded. Global kinematic measures of tongue activity were computed using articulatory stroke metrics, while point measures were gathered from one syllable in the target sentence. The first two formant frequencies of that syllable were measured. Statistical analysis revealed several significant changes over time and differences between genders. There was a significant increase in the syllable speed and decrease in sentence duration over time. The first formant was significantly lower over time correlating with decreased hull area, representing higher tongue position and smaller movements as speakers adapted to the sensors. Tongue displacement during the syllable production decreased over time; there was not a significant gender difference for displacement measures. The number of articulatory strokes decreased over time, suggesting improved articulatory steadiness. It can be concluded that participants demonstrated faster, smaller movements over time, but it is not clear how much of the change was a result of kinematic adaptation or task familiarity. Future research is needed to compare the direct relationship between kinematic, acoustic, and perceptual measures in response to the attachment of these EMA sensors.

This thesis examined the time course of speech adaptation prior to data collection when using an electromagnetic articulograph to measure speech articulator movements. The stimulus sentence and electromagnetic sensor placement were designed to be sensitive to changes in the fricatives /s/ and /ʃ/. Twenty native English speakers read aloud stimulus sentences before the attachment of six electromagnetic sensors, immediately after attachment, and again at 5, 10, 15 and 20 minutes after attachment. Participants read aloud continuously between recordings to encourage adaptation to the presence of the sensors. Audio recordings were rated by 20 native English listeners who were not part of the production study. After listening to five practice samples, these participants rated 150 stimuli (31 repeat samples) using a visual analog scale (VAS) with the endpoints labeled as precise and imprecise. An acoustic analysis of the recordings was done by segmenting the fricatives /s/ and /ʃ/ from the longer recording and computing spectral center of gravity and spectral standard deviation in Hertz. Durations of /s/, /ʃ/ and the sentence were also measured. Results of both perceptual and acoustic analysis revealed a change in speech precision over time, with all post attachment recordings receiving lower perceptual scores. Precision ratings beyond the ten minute recording remained steady. It can be concluded from the results that participants reached a height of adaptation after 10 minutes of talking with kinematic recording sensors attached, and that after the attachment of sensors, speech production precision did not at any point return to pre attachment levels.

The purpose of this study was to compare changes in acoustic and kinematic measures of articulation across soft, comfortable, and loud speech conditions. There were 19 participants, 9 male and 10 female, with age ranging from 20 to 34 with a median age of 25. Each participant had electromagnetic sensors glued to their tongue, jaw, and lips. It was anticipated that the acoustic measures would accurately reflect the kinematic measures of speech as articulation changed across the intensity levels. Vowel space area (VSA) and vowel articulation index (VAI) were computed from the three corner vowels, /α, i, u/. Articulatory-acoustic vowel space (AAVS), a sentence-level acoustic measure, was computed from the continuous formant histories for all voiced segments in a sentence. Kinematic-vowel space area (KVSA), kinematic-vowel articulation index (KVAI), and articulatory-kinematic vowel space (AKVS) were the kinematic equivalents of the acoustic measures, and were newly developed for the present study. Stroke metrics based on the speed history of the lingual movements were also used to reveal average kinematic features of the articulatory gestures in each participant's speech. The data revealed that the isolated acoustic and kinematic measures that used corner vowels (VSA, VAI. KVSA, KVAI) did not change significantly with intensity. The sentence-level continuous measures of articulatory working space (AAVS and AKVS) increased as speech intensity increased. The other sentence-level kinematic metrics also changed significantly with speech intensity, including increases in hull volume, onset speed, peak speed, mean speed, and distance. Stroke duration decreased as speech intensity increased. These findings suggest that measures based on isolated corner vowels are not as reflective as continuous measures of changes in articulatory movement in speech.

The present study examined the divided attention effects of three non-speech tasks on concurrent speech motor performance. These tasks targeted linguistic, cognitive, and manual motor activity. Participants included 60 healthy adults separated into three different age groups of twenty participants each: college-age (20s), middle-aged (40s), and older adults (60s). Each participant completed a speech task once in isolation and once concurrently with each of the three non-speech tasks: a semantic decision task, a quantitative comparison task, and a manual motor task. The non-speech tasks were also performed in isolation. The speech task involved repeating a target phrase each time a beep sounded, for a total of fourteen repetitions. Dependent measures for speech were derived from lip kinematic recordings from a head-mounted strain gauge system. Dependent measures for the other tasks included timed response counts and accuracy rates. Results indicated significant divided attention effects, impacting speech and nonspeech measures in the linguistic and cognitive conditions, and impacting speech measures in the manual motor condition. A significant age effect for utterance duration was also found, as well as a divided attention interaction with age for cognitive task accuracy. The results add to what is known about bidirectional interference between speech and other concurrent tasks, as well as age effects on speech motor control.