DYNAMIC LARYNGO-TRACHEAL CONTROL FOR AIRWAY MANAGEMENT IN DYSPHAGIA By AARON JOHN HADLEY Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Dissertation Advisor: Dr. Dustin J. Tyler Department of Biomedical Engineering CASE WESTERN RESERVE UNIVERSITY August 2013 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of: Aaron John Hadley candidate for the Doctor of Philosophy degree*. (signed) Dustin J Tyler, Ph.D (chair of the committee) Kenneth Gustafson Michael Broniatowski Patrizia Bonaventura (date) 05/30/2013 *We also certify that written approval has been obtained for any proprietary material contained therein. ii Table of Contents LIST OF FIGURES ........................................................................................................ VI LIST OF TABLES ........................................................................................................ VIII ACKNOWLEDGEMENTS .............................................................................................. IX ABSTRACT .................................................................................................................. 1 CHAPTER 1 : INTRODUCTION ...................................................................................... 3 DYSPHAGIA ......................................................................................................................... 3 PHASES OF SWALLOWING ....................................................................................................... 5 LARYNGEAL ANATOMY........................................................................................................... 8 LARYNGEAL ELEVATION ........................................................................................................ 11 INNERVATION OF LARYNGEAL ELEVATION (HN, CN XII) ............................................................. 16 RECURRENT LARYNGEAL NERVE ............................................................................................. 18 FUNCTIONAL ELECTRICAL STIMULATION FOR LARYNGEAL ELEVATION ............................................ 20 Surface Stimulation for Laryngeal Elevation ............................................................. 20 Intramuscular Stimulation for Laryngeal Elevation ................................................... 22 Nerve Stimulation for Laryngeal Elevation ................................................................ 25 FUNCTIONAL ELECTRICAL STIMULATION FOR VOCAL FOLD CONTROL ............................................. 28 Surface Stimulation of the Vocal Folds ...................................................................... 29 Implanted Stimulation of the Recurrent Laryngeal Nerve ......................................... 31 Transtracheal/Transesophageal stimulation ............................................................ 33 STIMULATION CONTROLLER .................................................................................................. 35 PALATOMETRY ................................................................................................................... 37 Electric Sensors .......................................................................................................... 38 Positive and Negative Pressure Recording ................................................................ 41 PROJECT SPECIFIC AIMS ....................................................................................................... 43 CHAPTER 2 - LARYNGEAL ELEVATION BY SELECTIVE STIMULATION OF THE HYPOGLOSSAL NERVE ............................................................................................... 47 ABSTRACT ......................................................................................................................... 47 INTRODUCTION .................................................................................................................. 49 METHODS ......................................................................................................................... 52 Surgery ....................................................................................................................... 52 Tetanic Stimulation and Video Recording ................................................................. 54 Nerve Stimulation and EMG Twitch Response .......................................................... 55 Video Analysis ............................................................................................................ 55 Selectivity Analysis ..................................................................................................... 57 iii RESULTS ........................................................................................................................... 58 Elevation .................................................................................................................... 58 Elevation Velocity ...................................................................................................... 61 Selectivity ................................................................................................................... 62 DISCUSSION ....................................................................................................................... 63 CONCLUSION ..................................................................................................................... 70 CHAPTER 3 - TARGETED TRANSTRACHEAL STIMULATION FOR VOCAL FOLD CLOSURE 73 ABSTRACT ......................................................................................................................... 73 INTRODUCTION .................................................................................................................. 74 METHODS ......................................................................................................................... 80 Modified Endotracheal Tube Design.......................................................................... 80 Surgical Preparation .................................................................................................. 81 Stimulation Trials ....................................................................................................... 83 Data Analysis ............................................................................................................. 84 RESULTS ........................................................................................................................... 87 DISCUSSION ....................................................................................................................... 93 CONCLUSION ..................................................................................................................... 98 CHAPTER 4 - NEURAL NETWORK DETECTION OF SWALLOWING USING PALATOMETRY .............................................................................................................................. 100 ABSTRACT ....................................................................................................................... 100 INTRODUCTION ................................................................................................................ 101 Palatometry ............................................................................................................. 104 Time Delay Artificial Neural Networks..................................................................... 106 MATERIALS AND METHODS: ............................................................................................... 108 Subjects and Palatometer Production ..................................................................... 108 Time Delay Artificial Neural Network Analysis ........................................................ 113 RESULTS ......................................................................................................................... 116 Palatometer Recordings .......................................................................................... 116 Intra-Subject and Population-Trained Networks ..................................................... 122 DISCUSSION ..................................................................................................................... 126 Optimizing Thresholds for FES systems ................................................................... 127 CONCLUSION ................................................................................................................... 131 CHAPTER 5 - DISCUSSION AND CONCLUSIONS ......................................................... 133 OVERVIEW OF DISSERTATION .............................................................................................. 133 CONTRIBUTION/RELATIONSHIP TO THE LITERATURE ................................................................. 134 FUTURE STUDIES .............................................................................................................. 136 iv Stimulation ............................................................................................................... 136 Palatometry ............................................................................................................. 138 APPLICATION OF RESEARCH ................................................................................................ 140 Rehabilitation .........................................................................................................