published_or_final_version / abstract / Speech and Hearing Sciences / Doctoral / Doctor of Philosophy

Hypokinetic dysarthria is a speech disorder that commonly occurs in individuals with Parkinson’s disease (PD). However, little is known about the speech characteristics and the effects of speech treatment on the speech of Mandarin speakers with hypokinetic dysarthria (henceforth, Mandarin speakers with PD). The purpose of this dissertation was to investigate the effects of intensive voice treatment on the speech intelligibility and acoustics of this population. This dissertation consisted of three papers. The first paper, “Acoustic and perceptual speech characteristics of native Mandarin speakers with Parkinson’s disease,” investigated the general speech characteristics of 11 Mandarin speakers with PD. Intelligibility and acoustic outcomes were reported and compared to seven age- and gender-matched neurologically healthy controls. Findings from this study showed that Mandarin speakers with PD exhibited decreased intelligibility, local pitch variation, vowel space area, speech rate, and rate variation. The second paper, “Effects of Loudness and Rate Manipulation Strategies on Speech Intelligibility and Acoustics of Mandarin Speakers With Parkinson’s Disease,” examined the effects of cueing to increase loudness and reduce speech rate on speech intelligibility and acoustics. Acoustic features including speech intensity, pitch range, pause duration, pause frequency, articulation rate, and vowel space area across 11 Mandarin speakers with PD were analyzed. The relationship between speech intelligibility and acoustic features was reported. Results showed that cueing for loud speech significantly increased intelligibility, but cueing for slow speech did not. Different cues had differential effects on the selected acoustic features. Cueing for loud speech resulted in increased vocal intensity and cueing for slow speech resulted in reduced articulation rate and increased pause frequency. In the loud speaking condition, greater vocal intensity and larger vowel space contributed to increased intelligibility, whereas in the slow condition, increased intensity, vowel space, as well as articulation rate, showed a trend toward contributing to increased intelligibility. The third paper, “The Effects of Intensive Voice Treatment on Intelligibility in Mandarin Speakers with Parkinson’s Disease: Acoustic and perceptual findings,” investigated the short- and long-term effects of intensive voice treatment (Lee Silverman Voice Treatment LOUD) on speech intelligibility and acoustics of nine Mandarin speakers with PD. All speakers showed increased intelligibility from pretreatment to immediate post-treatment, and the improvement was maintained at the 6-month follow-up. Five acoustic features were analyzed. Speech intensity, vowel space, and speech rate changed significantly in positive directions immediately post-treatment, and the increases were retained up to six months. Global pitch variation increased immediately post-treatment but not at the 6-month follow-up. No changes were found in local pitch variation following treatment. Self-reported intelligibility, voice quality, confidence, frustration level, and communicative participation changed positively immediately after the completion of treatment and at the 6-month follow-up. To conclude, the speech characteristics of Mandarin speakers with PD were generally consistent with those of English speakers with PD, except that speech was slower in the Mandarin speakers. Cueing to increase loudness and reduce rate had different effects on speech intelligibility and production, with louder speech yielding greater intelligibility and acoustic benefits. Following intensive voice treatment (LSVT LOUD), Mandarin speakers with PD increased their vocal intensity. Speech intelligibility, vowel space, global pitch variation and speech rate increased as a result of the treatment. Thus, some differences between Mandarin and English dysarthria and effects of cueing might be present, but as for English speakers, intensive treatment (specifically LSVT LOUD) focusing on increasing vocal intensity shows promise for increasing intelligibility and quality of life in Mandarin speakers with hypokinetic dysarthria. Future studies should include a larger number of participants and probe the effects of behavioral speech modifications and intensive voice treatment on lexical tone, and consider which physiological mechanisms might be associated with production of lexical tone, given that lexical tone is often crucial to differentiating word meaning in Mandarin.

The phonological awareness skills of children with language disorders has been well addressed throughout the literature. Research into the phonological awareness skills of children with highly unintelligible speech, however, is still in its infancy. One published study has looked at the relationship between phonological awareness skills in children with persistent phonological impairments and in children with normal phonology (Webster & Plante, 1992). Significantly higher scores were recorded on three of the four phonological awareness measures for the children with normal phonology As phonology improved, so did the children's phonological awareness skills. The purposes of the present study were to determine if there is an improvement in phonological awareness skills of children with highly unintelligible speech who receive speech sound intervention services, and to determine if there is a difference in phonological awareness skills between children who receive a phoneme-oriented treatment approach and those who receive a phonological cycling treatment approach. Children who took part in a larger study (Buckendorf, 1996) in which the effectiveness of the two treatment approaches was examined, were given the Assessment of Metaphonological Skills-Prekindergarten (Hodson, 1995) early in the course of treatment and again 2 to 3 months later. The following specific questions were addressed: 1. Is there an increase in phonological awareness skills for children who receive articulation/phonological intervention? 2. Is there a difference in the amount of improvement of phonological awareness skills for children who receive a phoneme-oriented treatment approach as compared with children who receive a phonological cycling treatment approach? To test if the subject's phonological awareness skills improved from pretest to posttest, a one tailed !-test for paired differences, and the Wilcoxon Matched-Pairs Signed-Ranks test were performed. Results on both of these analyses indicated a statistically significant improvement between pretest and posttest scores. To test if there is a difference in the improvement of phonological awareness skills between the two groups, a !-test for independent samples of group and the Mann-Whitney LI-Wilcoxon Rank Sum W-Test were performed on pretest, posttest, and pretest-to-posttest. Results on both analyses indicated no statistically significant differences between the two groups on any of these variables.

This single-subject study was designed to compare the effectiveness of two phonological-based treatment approaches with a preschool male with unintelligible speech characterized by multiple deficient phonological patterns. Four phonological patterns were chosen as targets based on results of the Assessment of Phonological ProcessesRevised (APP-R} (Hodson, 1986), as analyzed by the Computer Analysis of Phonological Deviation (CAPO) (Hodson, 1992a). The subject participated in 60-minute intervention sessions three times a week over an 8-week period. The phonological cycling approach (Hodson & Paden, 1991) was the focus of 4 weeks of intervention, and the minimal pairs approach (Tyler, Edwards, & Saxman, 1987) was the focus of 4 weeks of intervention. Remediation programs were alternated every 2 weeks, and began with the phonological cycling approach. Results were measured through pretests and posttests of the APP-R, as well as baseline and generalization probes that were administered periodically. Results of the CAPD indicated minimal changes between pretest and posttest scores for all of this subject's targeted phonological patterns (i.e., consonant sequences I stridents, velars, liquid /1/, and liquid /r/). In addition, no significant differences in scores were noted between remediation programs. Results of probe measurements indicated little, if any, generalization to targeted and non-targeted words in an imitated word probe task for any of the targeted patterns, except for the target phonological pattern of consonant sequences I stridents after the phonological cycling approach. This finding may suggest that the phonological cycling approach was more effective for this subject than the minimal pairs approach.

Intelligibility refers to how recognizable a speaker's words are to the listener. Severity, a broader but closely related concept, incorporates intelligibility, disability, and handicap. Many factors influence intelligibility, including speech sound production, voice, and prosody, as well as a number of linguistic and contextual factors. Clinicians and researchers in the field of speechlanguage pathology require accurate measures of intelligibility and severity to assess and describe communicative functioning and to measure change over time. Determining the most accurate and efficient measurement approaches has been the focus of recent attention in the field. This study was a preliminary investigation of the relationship between the Articulation Competence Index (ACI), a severity metric, and the percentage of words understood in continuous speech, the standard measure of intelligibility. Specifically, the study addressed the research question: Is there a significant correlation between the Articulation Competence Index (ACI) and percentage of words understood in samples of continuous speech of 4- and 5-year-olds with varying levels of phonological competence? Subjects were thirty 4- and 5-year-olds from the Portland metropolitan area. Four listeners calculated percentage-of-words scores for each child's 100-word speech sample. These scores were compared to ACI scores calculated by the investigator for each of the samples. The data were analyzed using the Pearson productmoment correlation (Pearson£). A moderately strong correlation (£ = .71 to .81) was found between the ACI and percentage of words understood. Squaring the correlation coefficients resulted in values for £ 2 of .50 to .66, indicating that the ACI accounts for more than half the variability of continuous speech intelligibility.

The purpose of this investigation was to determine the comparative effectiveness of two articulation carry-over techniques. It was hoped that through this comparison answers regarding carry-over results could be ascertained for purposes of aiding public school clinicians currently spending the majority of management time on carry-over. If one technique was found to be superior, its use among speech pathologists might aid in changing this time allocation trend.

The purpose of this investigation was to determine if children labeled as “severe” functional articulation disordered, who had been enrolled in public school speech programs for one year or more, exhibited dyspraxic-like characteristics. Twenty individuals between the ages of 8 and 11 were chosen from the Gresham Public Schools, Lynch Public Schools, Portland Public Schools, Rockwood Public Schools and the Crippled Children’s Division, University of Oregon Medical School to serve as subjects for the three groups in this study. Eight subjects who comprised the experimental group were 11 severe11 functional articulation disorders and were selected from the public schools. Each misarticulated four or more phonemes, consistently or inconsistently, in isolation, syllables, words or conversation; each had made little or very slow progress according to his speech clinician and each had been enrolled in speech management for one year or more as a functional articulation case. Eight subjects in the normal control group were individuals selected from the public schools, with no speech or language problems. Each had never been enrolled in nor recommended for a speech intervention program. Four subjects in the dyspraxic control group were selected from the University of Oregon Medical School. Prior to the date of this investigation, each had been diagnosed as displaying developmental dyspraxia, dyspraxia of speech or verbal dyspraxia. The Modified Apraxia Battery (NAB) utilized in this investigation was a nonstandardized battery consisting of a verbal section and a nonverbal section. The verbal section was composed of ten subtests designed to delineate the presence of a dyspraxia of speech; the nonverbal section was composed of one subtest designed to delineate an oral apraxia and one subtest designed to delineate a limb apraxia. The results of this study revealed a highly significant difference in performance on the verbal section between the normal subjects and the “severe” functional articulation subjects with the normals performing better. A highly significant difference also was found between the normal subjects and the dyspraxic subjects with the normals performing better on the verbal section of the MAB. No significant difference was revealed, however, between the dyspraxics and the “severe” functional articulation cases. It was inferred, therefore, that these two groups performed in a similar manner because they exhibited similar verbal characteristics. “Severe” functional articulation disordered subjects were, therefore, found to exhibit verbal dyspraxic-like characteristics. No significant difference in performance was shown on the nonverbal section among the three groups. It appears the verbal section of the Modified Apraxia Battery much more effectively differentiates those displaying dyspraxic-like characteristics from those who do not than does the nonverbal section. Chi square analysis of items on the NAB supported this contention further suggesting subsection 3, Multisyllabic Words and subsection 6, Sentences are the most discriminating verbal items.

Speech-language pathologists are constantly trying to use the most efficient and effective assessments to obtain information about the phonetic inventory, speech sound errors, and phonological error patterns of children who are suspected of having a speech sound disorder. These assessments may involve a standardized measure of single words and/or sentences and a non standardized measure, such as a spontaneous speech sample. While research has shown both of these types of assessments to give clinicians information about a child's speech production abilities, the use of delayed imitation tasks, either words or sentences, has not been a widely studied topic and has produced conflicting results when researched. The purpose of the present study was to examine speech sound production abilities in children with a speech sound disorder in a single-word task, an imitated sentence task, and spontaneous speech sample to compare their results of speech sound errors, phonological error patterns, and time administration. The study used the Phonological and Articulatory Bilingual Assessment - English version (PABA-E, Gildersleeve-Neumann , 2008), a formal assessment for identifying children who may have a speech sound disorder. Three male children, between the ages of 4;0 and 5;4 (years;months), participated in this study. All participants were being treated by a speech-language pathologist for a diagnosed speech sound disorder and had hearing within normal limits. The results of the study showed that the majority of participants produced the highest number of speech sounds targeted within the imitated sentence task. Participants attempted and produced the least amount of speech sounds on their spontaneous speech sample. The assessment with the highest percentage of accurately produced consonants was the imitated sentence task. The majority of participants produced a higher number of error patterns in their single-word and imitated sentence task. In terms of efficiency and effectiveness, the imitated sentence task took the least amount of time to administer and transcribe.

The purpose of this study was to compare the speechreading abilities of elementary school-age children with mild to severe articulation disorders with those of children with normal articulation. Speechreading ability, as determined by a speechreading test, indicates how well a person recognizes the visual cues of speech. Speech sounds that have similar visual characteristics have been defined as visemes by Jackson in 1988 and can be categorized into distinct groups based on their place of articulation. A relationship between recognition of these visemes and correct articulation was first proposed by Woodward and Barber in 1960. Dodd, in 1983, noted that speechread information shows a child how to produce a sound, while aural input simply offers a target at which to aim.

The purpose of this study was to explore the relationship between occurrence of 10 phonological processes, singly and in groups, with mean percentage of intelligibility of connected speech samples. Participants in the study included 4 adult listeners (3 females, one male) and 46 speakers aged 48 to 66 months (16 females, 30 males). Percentage of occurrence scores for phonological processes (independent variables) were obtained by the administration of The Assessment of Phonological Processes - Revised (Hodson, 1986). Percentage of intelligibility for 100-word connected speech samples (dependent variables) were obtained by orthographic transcription (words understood divided by 100). The single processes showing the strongest negative correlation with intelligibility of connected speech included consonant sequence omission, glide class deficiency, syllable omission, and velar class deficiency, with reliability beyond the .001 level. The combination of consonant sequence omission, syllable omission, nasal class deficiency, and velar class deficiency accounted for 83% of the variance in the dependent variable. In this equation, consonant sequence omission alone accounted for 70% of the variance. Significance is beyond the .05 level for these measures. Results of the study lead to the recommendation that the following phonological processes are high priority targets for remediation: consonant sequence omission, syllable reduction and glide class deficiency, syllable reduction, and velar class deficiency.