PHONOLOGICAL PROCESSING ABILITIES OF ADULTS WHO STUTTER by Kristin M. Pelczarski B. A. in Speech and Hearing Science, The George Washington University, 1997 M. A. in Communication Science and Disorders, University of Pittsburgh, 2003 Submitted to the Graduate Faculty of the School of Health and Rehabilitation Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy University of Pittsburgh 2011 i UNIVERSITY OF PITTSBURGH SCHOOL OF HEALTH AND REHABILITATION SCIENCES This dissertation was presented by Kristin M. Pelczarski It was defended on November 4, 2011 and approved by Michael W. Dickey, Assistant Professor Julie A. Fiez, Professor Paula Leslie, Associate Professor Dissertation Director: J. Scott Yaruss, PhD, Associate Professor ii Copyright © by Kristin M. Pelczarski 2011 iii PHONOLOGICAL PROCESSING ABILITIES IN ADULTS WHO STUTTER Kristin M. Pelczarski, Ph.D University of Pittsburgh, 2011 This study investigated phonological awareness, phonological memory and rapid automatic naming abilities of adults who stutter and typically fluent peers. Many theorists posit that a delay or breakdown occurs during “phonological encoding,” or the retrieval or construction of phonological segments (Howell & Au-Yeung, 2002; Perkins, Kent & Curlee, 1991; Postma & Kolk, 1993; Wingate 1988). Efficient phonological encoding is predicated upon the ability to segment phonological representations in a rapid, precise manner. According to current theories, a delay or incomplete retrieval of lexical segments could impede the execution of the articulatory plan, thereby resulting in disfluent speech. Unfortunately, the process of phonological encoding is not directly observable and must therefore be explored though alternate processes that reflects its incremental nature. Phonological awareness, phonological memory and rapid automatic naming can be examined to accomplish this task. Several core mechanisms are utilized during phonological processing, and a deficit in any of these mechanisms could account for performance differences in phonological processing tasks. Completion of these tasks is dependent upon the quality of phonological representations in the lexicon, the ability to construct novel phonological codes online, and the ability to maintain phonological representations in memory. The process of redintegration, whereby pre-existing lexical-semantic knowledge is used iv to supplement decaying or delayed phonological code (Hulme et al., 1997), can also play an important role in the completion of phonological processing tasks. Participants completed several tasks examining different aspects of their phonological processing abilities. Significant between-group differences were revealed on nonlexical phonological awareness tasks, nonword repetition tasks, and rapid automatic naming tasks that used lexical stimuli. Adults who stutter performed significantly less well than typically fluent adults on tasks that used nonlexical stimuli. Adults who stutter appear to rely heavily on lexical- semantic information (redintegration) to bolster lower performance in other aspects of phonological encoding. Participants in both groups performed equally well on tasks that used lexical stimuli but not on tasks with nonlexical stimuli, indicating that between-group differences in phonological encoding exist. Differences in core mechanisms of phonological processing may reveal subtle linguistic differences that may contribute to an unstable speech system in people who stutter. v TABLE OF CONTENTS ACKNOWLEDGEMENTS ....................................................................................................................... xvii 1.0 INTRODUCTION .................................................................................................................................. 1 2.0 LITERATURE REVIEW ....................................................................................................................... 5 2.1 TYPICAL LANGUAGE FORMULATION ............................................................................. 6 2.1.1 An information processing model of speech perception and production ................... 9 2.1.2 Contribution of phonological working memory to language ................................... 15 2.2 PHONOLOGICAL PROCESSING ......................................................................................... 18 2.2.1 Phonological awareness ........................................................................................... 18 2.2.2 Phonological memory .............................................................................................. 30 2.2.3 Rapid automatic naming .......................................................................................... 34 2.2.4 Core mechanisms ..................................................................................................... 35 2.2.5 Summary .................................................................................................................. 37 2.3 PHONOLOGICAL PROCESSING IN INDIVIDUALS WHO STUTTER ............................ 38 2.3.1 Phonological awareness and individuals who stutter ............................................... 41 2.3.2 Phonological memory and individuals who stutter .................................................. 54 2.3.3 Rapid automatic naming and individuals who stutter .............................................. 60 2.4 PHONOLOGICAL PROCESSING AND STUTTERING SUMMARY ................................ 61 2.5 RESEARCH QUESTIONS ..................................................................................................... 63 3.0 METHOD ............................................................................................................................................. 70 vi 3.1 PARTICIPANTS ..................................................................................................................... 70 3.2 INCLUSION AND MATCHING CRITERIA ........................................................................ 71 3.2.1 Speech fluency ......................................................................................................... 71 3.2.2 Group matching criteria ........................................................................................... 72 3.3 BACKGROUND DATA ......................................................................................................... 74 3.3.1 Reading history ........................................................................................................ 74 3.3.2 Vocabulary ............................................................................................................... 74 3.4 INSTRUMENTATION ........................................................................................................... 75 3.5 DATA COLLECTION ............................................................................................................ 76 3.5.1 Phonological awareness tasks with lexical stimuli .................................................. 76 3.5.2 Phonological awareness tasks with nonword stimuli ............................................... 78 3.5.3 Phonological awareness reaction times.................................................................... 79 3.5.4 Phonological memory .............................................................................................. 87 3.5.5 Nonword repetition .................................................................................................. 88 3.5.6 Rapid automatic naming .......................................................................................... 89 3.6 PROCEDURES ....................................................................................................................... 90 3.7 MEASUREMENT RELIABILITY ......................................................................................... 92 3.7.1 Standardized test reliability and validity .................................................................. 92 3.7.2 Inter- and intra-rater reliability ................................................................................ 92 3.8 ANALYSES ............................................................................................................................. 94 4.0 RESULTS ............................................................................................................................................. 95 4.1 DESCRIPTIVE MEASURES .................................................................................................. 95 4.2 PHONOLOGICAL AWARENESS WITH LEXICAL STIMULI .......................................... 96 4.2.1 Phonological awareness composite score ................................................................ 97 4.3 PHONOLOGICAL AWARENESS WITH NON-LEXICAL STIMULI ................................ 98 vii 4.3.1 Alternate phonological awareness composite scores ............................................... 99 4.4 PHONOLOGICAL AWARENESS REACTION TIMES ..................................................... 101 4.4.1 Lexical decision accuracy ...................................................................................... 101 4.4.2 Lexical decision reaction times - lexical status ...................................................... 103 4.4.3 Lexical decision reaction times - length effect ...................................................... 104 4.4.4 Silent phoneme blending/lexical decision task accuracy ....................................... 105 4.4.5 Silent