School of Psychology Human Communication Science The Relationship between Early Feeding and Communication Development in Preterm and Term Infants: Birth to 12 months. Sharon J Smart This thesis is presented for the Degree of Doctor of Philosophy of Curtin University of Technology October 2008 Declaration To the best of my knowledge and belief this thesis contains no material previously published by any other person except where due acknowledgment has been made. This thesis contains no material which has been accepted for the award of any other degree or diploma in any university. Signature: …………………………………… Date: …………………………………… ii TABLE OF CONTENTS Contents Page Table of Contents .........................................................................................................ii List of Tables .............................................................................................................vii List of Figures ............................................................................................................. xi Abstract ..................................................................................................................... xvi Summary of Contents................................................................................................ xix List of Publications Arising from the Thesis ............................................................ xxi Scholarships and Awards ........................................................................................xxiii Acknowledgements................................................................................................. xxiv 1.0 Introduction.......................................................................................................... 1 1.1 Feeding and speech .......................................................................................... 1 1.2 Integrated theoretical framework ..................................................................... 2 1.3 Normal development........................................................................................ 6 1.3.1 Embryologic development ........................................................................ 6 1.3.2 Birth to 6 months....................................................................................... 7 1.3.3 6 to 12 months......................................................................................... 10 1.4 Prematurity................................................................................................. 13 1.4.1 Feeding.................................................................................................... 14 1.4.2 Communication....................................................................................... 16 1.4.3 Developmental outcomes........................................................................ 17 1.4.4 Maternal factors ...................................................................................... 19 1.4.5 Environmental influences ....................................................................... 20 1.5 Summary ........................................................................................................ 21 2.0 Related and unrelated motor control systems for feeding and speech development ................................................................................................... 22 2.1 Related motor control systems....................................................................... 22 2.1.1 Evolutionary theory................................................................................. 23 2.1.2 Anatomical relations for feeding and speech production........................ 23 2.1.3 Neurologically impaired populations...................................................... 28 2.2 Unrelated motor control systems or ‘task dependent’ hypothesis ................. 30 2.2.1 Non-oral feeding ..................................................................................... 32 iii 2.2.2 Nutritive and non-nutritive sucking ........................................................ 32 2.3 Summary ........................................................................................................ 33 2.4 Project aims and hypotheses .......................................................................... 33 3.0 Development of feeding assessments ................................................................ 35 3.1 Background .................................................................................................... 35 3.1.1 Evaluation of existing assessment tools.................................................. 35 3.1.2 Development of a theoretical framework................................................ 50 3.1.3 Development of feeding assessments and the initial questionnaire........ 55 3.2 Methodology .................................................................................................. 59 3.2.1 Participants.............................................................................................. 59 3.2.2 Materials.................................................................................................. 59 3.2.3 Procedure ................................................................................................ 59 3.3 Results............................................................................................................ 60 3.3.1 Inter-observer agreement ........................................................................ 61 3.3.2 Observer agreement ................................................................................ 61 3.4 Discussion ...................................................................................................... 63 4.0 Feeding and Communication Relations ............................................................. 65 4.1 Background .................................................................................................... 65 4.2 Methodology .................................................................................................. 65 4.2.1 Participants.............................................................................................. 66 4.2.2 Materials.................................................................................................. 68 4.2.3 Procedure ................................................................................................ 70 4.2.4 Scoring .................................................................................................... 72 4.3 Results............................................................................................................ 73 5.0 Contributing Factors .......................................................................................... 74 5.1 Infant factors .................................................................................................. 74 5.1.1 Infant questionnaire................................................................................. 74 5.1.2 Developmental review ............................................................................ 77 5.2 Maternal factors ............................................................................................. 80 5.2.1 Initial questionnaire................................................................................. 80 5.2.2 Developmental review ............................................................................ 82 5.3 Environmental factors .................................................................................... 83 5.3.1 Initial questionnaire................................................................................. 83 5.3.2 Developmental review ............................................................................ 84 iv 5.3.3 Home Screening Questionnaire .............................................................. 84 5.4 Summary ........................................................................................................ 85 6.0 Feeding Development ........................................................................................ 86 6.1 Overall efficiency - duration, volume and frequency ................................ 87 6.1.1 Feeding observation ................................................................................ 87 6.1.2 Feeding questionnaire ............................................................................. 87 6.2 Reflexes.......................................................................................................... 88 6.2.1 Feeding observation ................................................................................ 88 6.2.2 Feeding questionnaire ............................................................................. 88 6.3 Symbolic planning (intentionality) ................................................................ 89 6.3.1 Feeding observation ................................................................................ 89 6.3.2 Feeding questionnaire ............................................................................. 89 6.4 Sensorimotor planning ................................................................................... 89 6.4.1 Feeding observation ................................................................................ 89 6.4.2 Feeding questionnaire ............................................................................. 91 6.5 Motor programming......................................................................................