Phonological Encoding in Adults Who Clutter and Adults Who Stutter PhD School of Psychology and Clinical Language Sciences Jess Bretherton-Furness August 2016 Acknowledgements Thanks to David Ward for encouraging me to undertake this project and for being so supportive throughout its completion. Also thanks to Douglas Saddy for his support and ideas especially when creating my stimuli. Special thanks to Bobby Stuijfzand and Dr Kou Murayama for helping me work out how to analyse my data, to Becky Lucas for her time and patience and to Suzannah, Tiffany, Birthe and Faith for cake, positivity and being the best office buddies a girl could ask for. Declaration I confirm that this is my own work and the use of all material from other sources has been properly and fully acknowledged. The work presented in chapter six has been published. Bretherton-Furness, J., Ward, D., & Saddy, D. (2016). Creating a non-word list to match 226 of the Snodgrass standardised picture set. i Table of Contents 1 CHAPTER ONE .......................................................................... 1 1.1 Introduction ............................................................................................................................ 1 1.1.1 Definitions ....................................................................................................................... 1 1.1.2 Epidemiology of stuttering and cluttering ...................................................................... 3 1.1.3 Causes of Stuttering and Cluttering ................................................................................ 4 1.1.4 This Thesis ....................................................................................................................... 8 2 CHAPTER TWO ......................................................................... 9 2.1 Defining cluttering .................................................................................................................. 9 2.1.1 Current definitions of cluttering ..................................................................................... 9 2.1.2 The lowest common denominator (LCD) definition of cluttering ................................ 10 2.1.3 Subgroups in cluttering and the cluttering spectrum ................................................... 11 2.1.4 Empirical data on the characteristics of cluttering ....................................................... 12 2.2 Defining Stuttering ................................................................................................................ 14 2.2.1 Current definitions of stuttering ................................................................................... 14 2.2.2 Characteristics of stuttering ......................................................................................... 15 2.3 Assessment of stuttering and cluttering ............................................................................... 17 2.3.1 Assessment of cluttering .............................................................................................. 17 2.3.2 Assessment of stuttering .............................................................................................. 17 2.4 Differential Diagnosis of Stuttering and Cluttering .............................................................. 18 2.5 Neurological data from Stuttering and Cluttering ................................................................ 22 2.5.1 Neurological cause of cluttering ................................................................................... 22 2.5.2 Empirical neurological data on cluttering ..................................................................... 23 2.5.3 Empirical neurological data on stuttering .................................................................... 24 2.6 Phonological encoding and stuttering and cluttering .......................................................... 27 2.6.1 Theories ........................................................................................................................ 27 2.6.2 Data from studies investigating phonological encoding in stuttering .......................... 30 ii 2.6.3 Non-word repetition ..................................................................................................... 31 2.6.4 Priming .......................................................................................................................... 33 2.6.5 Sound blending and elision ........................................................................................... 35 2.6.6 Rhyme Judgement ........................................................................................................ 36 2.6.7 Phoneme monitoring tasks ........................................................................................... 37 2.6.8 Phonological encoding and working memory .............................................................. 38 2.6.9 Syllabic stress ................................................................................................................ 40 2.6.10 Phonological encoding and cluttering .......................................................................... 41 2.7 Self-Repair and Monitoring of Speech .................................................................................. 42 2.8 Non-speech motor control ................................................................................................... 45 2.9 Difficulties studying fluency .................................................................................................. 47 2.10 Directions for further research ............................................................................................. 48 2.11 The pilot study ...................................................................................................................... 48 2.11.1 Rationale ....................................................................................................................... 48 2.11.2 Hypotheses for pilot tasks ............................................................................................ 49 3 CHAPTER THREE PILOT ............................................................ 51 3.1 Method ................................................................................................................................. 51 3.1.1 Participants ................................................................................................................... 51 3.1.2 Ethical considerations ................................................................................................... 51 3.1.3 Tasks ............................................................................................................................. 51 3.1.4 Analysis ......................................................................................................................... 55 3.2 Results ................................................................................................................................... 57 3.2.1 Sound detection: accuracy and response times ........................................................... 57 3.2.2 Morphological detection .............................................................................................. 60 3.2.3 Rhyme detection ........................................................................................................... 62 3.2.4 Verbal fluency ............................................................................................................... 65 3.2.5 Planning - Make a sentence .......................................................................................... 65 3.2.6 Planning - Jumbled sentences ...................................................................................... 66 iii 3.2.7 Sentence comprehension ............................................................................................. 67 3.2.8 Sentence production .................................................................................................... 69 3.3 Discussion ............................................................................................................................. 71 3.4 Going forward ....................................................................................................................... 73 4 CHAPTER FOUR MAIN STUDY .................................................. 74 4.1 Reaction time tasks ............................................................................................................... 74 4.1.1 Reaction time task one ................................................................................................. 74 4.1.2 Reaction time task two ................................................................................................. 74 4.2 Phoneme monitoring tasks ................................................................................................... 75 4.2.1 Real word phoneme monitoring (RWPM) .................................................................... 75 4.2.2 Non-word phoneme monitoring (NWPM) .................................................................... 76 4.2.3 Phoneme monitoring in silent reading (PMSR) ............................................................ 76 4.2.4 Phoneme monitoring in silent picture naming (SPN) ................................................... 77 4.3 Syllable detection tasks .......................................................................................................