UTTERANCE LENGTH AFFECTS ARTICULATION IN CHILDREN WITH SPEECH SOUND DISORDERS by SEAN SNAPP Submitted in partial fulfillment of the requirements for the degree of Master of Arts Department of Psychological Sciences CASE WESTERN RESERVE UNIVERSITY May, 2018 1 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis of Sean Snapp candidate for the degree of Master of Arts*. Committee Chair Barbara Lewis Committee Member Lisa A. Freebairn Committee Member Vera Tobin Committee Member Jennell Vick Date of Defense March 30, 2018 *We also certify that written approval has been obtained for any proprietary material contained therein. 2 Table of Contents Table of Contents 2 List of Tables 3 List of Figures 4 Acknowledgements 5 Abstract 6 Literature Review Introduction 7 Utterance Length in Imitative Speech 8 Utterance Length in Evaluation 9 Utterance Length in Treatment 10 Goals of the Present Study 14 Methods Participants 15 Procedures 16 Results 20 Discussion 25 Appendices Appendix A: Individual Data on Productions of /ð/ by Utterance Length in Morphemes 31 Appendix B: Words in which productions of /ð/ occurred and the accuracy of the /ð/ productions 35 Appendix C: Relationship between MLU and % of productions of /ð/ in error 36 References 37 3 List of Tables Table 1. Demographic characteristics of study participants 15 Table 2. Results of standardized measures 16 4 List of Figures Figure 1. Percent productions of /ð/ in error by length of utterance as measured in morphemes 21 Figure 2. Eleven participants showing greater proportion of errors on 8-morpheme utterances compared with 3-morpheme utterances 22 Figure 3. Six participants showing greater proportion of errors as utterance length increases 23 Figure 4. Percent productions of /ð/ in error across utterance positions 24 Figure 5. Percent productions of /ð/ in error across utterance lengths and positions 24 Figure 6. Correlation between percent productions on /ð/ in error and MLU 25 5 Acknowledgements This research was supported by grant DC00528 from the National Institutes of Health, National Institute on Deafness and Other Communication Disorders (Barbara A. Lewis). 6 Utterance Length Affects Articulation in Children with Speech Sound Disorders Abstract by SEAN SNAPP Objective: The objective of this study was to investigate the effects of utterance length and utterance position on proportion of errors on voiced-th (/ð/) by preschool-age children with speech sound disorders (SSD). Method: Productions of /ð/ in spontaneous language samples from 20 children with SSD were categorized as correct or in error. These productions were pooled to determine patterns of proportions of errors across utterance lengths and positions. Results: A greater proportion of productions of /ð/ in error were found in 8-morpheme utterances than in 3-morpheme utterances. A gradual increase in proportion of errors was observed in productions of /ð/ occurring in utterance- medial positions. Conclusions: Some support was found for utterance length effects on articulation and stronger support was found for utterance position effects. Utterance length and position should receive consideration by SLPs in the assessment and treatment of preschool children with SSD. 7 Utterance Length Affects Articulation in Children with Speech Sound Disorders Literature Review Introduction Speech sound disorders (SSD) affect 2% to 25% of children ages 5 to 7 years (Law, Boyle, Harris, Harkness, & Nye, 2000). Children with SSD form a significant portion of pediatric speech-language pathologists’ (SLPs’) caseloads. Data from the American Speech-Language-Hearing Association’s (ASHA’s) National Outcomes Measurement System (NOMS) have shown that approximately 75% of pre-K students treated by SLPs received therapy for articulation or intelligibility (Mullen & Schooling, 2010). Diminished intelligibility is the hallmark characteristic of SSD, with perception, production, and mental representation of consonants and vowels, phonotactics, and prosody affected to greater or lesser degree in each child (International Expert Panel on Multilingual Children’s Speech, 2012). Among the numerous factors affecting articulation in children with SSD that have been widely accepted in clinical practice, utterance length stands out for its ubiquity as a consideration in assessment and evaluation despite a relatively low level of evidence from research. Investigation of utterance length effects on articulation has been focused on imitative speech, elicitation of samples in evaluation, and target selection in treatment (Schmauch, Panagos, & Klich, 1978; Panagos, Quine, & Klich, 1979; McLeod, Rosenthal, & Hayes, 1994; Wolk and Meisler, 1998; Masterson, Bernhardt, and Hofheinz, 2005; Healy and Madison; 1987; DuBois & Bernthal, 1978; Morrison & Shriberg, 1992; Klein, 1996). This has left a gap in knowledge of utterance length effects on articulation errors during the spontaneous speech of children with SSD. This is an area 8 worthy of investigation because spontaneous speech will more accurately reflect natural performance compared with imitative speech and will demonstrate potential issues related to generalization of treated phonemes. Utterance Length in Imitative Speech In imitative speech, increased articulation errors, especially on late-developing sounds, have been found in a sentence context compared to a noun phrase context in both children with comorbid speech and language disorders and children with SSD only (Schmauch, Panagos, & Klich, 1978; Panagos, Quine, & Klich, 1979). These findings, which support the commonly held notion that increased utterance length is related to an increased rate of errors of articulation, should be interpreted cautiously. The use of imitation to elicit all productions of short and long phrases may have influenced participants’ speech and therefore may not have reflected their performance in spontaneous speech. The use of imitation to elicit responses introduces aspects of memory that were not controlled for and may have confounded the results. Shorter utterances may have been easier to store in short-term memory and repeat with greater precision than longer utterances. In addition, these studies investigated productions of 14- 20 early- to late-developing phonemes with limited productions of each. In their analysis of the results, differences in the production of different phonemes was not considered. This makes it difficult to draw conclusions about the effect of utterance length on any one phoneme, as it is not known whether utterance length had differential effects based on phoneme. Variables such as manner, place, and order of acquisition could have confounded the results. Coarticulation effects, including the influence of phonological processes, were also not considered. 9 Utterance Length in Evaluation In order to rule out the presence of SSD, or alternatively, to determine the type and severity of a child’s disorder, SLPs complete a comprehensive evaluation that typically includes pre-screening, interviewing parents, assessing stimulability and intelligibility, and elicitation of single words (typically through standardized testing measures) and connected speech, including conversational speech (McLeod & Baker, 2014). One purpose of the speech sample is to determine the developmental appropriateness child’s phonetic inventory and to select target speech sounds for therapy. In a national survey of assessment practices for children with SSD that included 312 ASHA-affiliated SLPs across the United States, 74.1% of respondents reported always using single-word tests to determine percentile rank and score (17.8% reported sometimes using single-word tests); only 36.2% of respondents reported always using a connected speech sample (43.7% reported sometimes using a connected speech sample) (Skahan, Watson, & Lof, 2007). Given the important role that choosing a representative speech sample has in maintaining the integrity of an assessment of articulation and phonology, it is imperative that SLPs be able to justify the use of one type of speech sample over the other with evidence from research. Research investigating the relative accuracy of single-word sampling and conversational speech sampling in the assessment of children with SSD has produced mixed results. Many studies have found single-word tasks and conversational speech sampling to produce comparable results (e.g., McLeod, Hand, Rosenthal, & Hayes, 1994; Wolk and Meisler, 1998; Masterson, Bernhardt, and Hofheinz, 2005). Other studies have found significant differences in the interpretations of data collected single-word and 10 conversational speech samples. For example, Healy and Madison (1987) found a significantly greater proportion of errors were produced in connected speech samples by children with SSD than in single word utterances. Similarly, DuBois & Bernthal (1978) found that children with SSD produced significantly more errors in a continuous speech task than in a modeled continuous speech task or a spontaneous picture-naming task. Morrison & Shriberg (1992) found that productions of established sounds of children with SSD were more accurate in conversational speech and emerging sounds were more accurate in single-word sampling. The differing conclusions of these studies suggest the presence of confounding variables affecting accuracy of speech sound production and presence of phonological processes that have yet to be considered. Coarticulation effects, for instance, were not considered. In single-word testing, these