THE EFFECT OF SEGMENTAL VIBRATION THERAPY ON COGNITIVE PROCESSING AND BALANCE IN OLDER ADULTS. A dissertation submitted to Kent State University in partial fulfillment to the requirements for the degree of Doctor of Philosophy by Nhlalala Y.Z. Mavundza May 2019 © Copyright All rights reserved Dissertation written by Nhlalala Y.Z. Mavundza B.Sc., Stellenbosch University, 2011 B.Sc. (Honors), Stellenbosch University, 2012 Ph.D., Kent State University, 2019 Approved by Angela L. Ridgel, Ph.D. , Chair, Doctoral Dissertation Committee Eric M. Mintz, Ph.D. , Members, Doctoral Dissertation Committee Colleen M. Novak, Ph.D. Kimberly S. Peer, Ph.D. Jacob E. Barkley, Ph.D. Accepted by Ernest J. Freeman, Ph.D._____, Director, School of Biomedical Sciences James L. Blank, Ph.D. , Dean, College of Arts and Sciences TABLE OF CONTENTS TABLE OF CONTENTS .................................................................................. iii LIST OF FIGURES .......................................................................................... v LIST OF TABLES .......................................................................................... viii ACKNOWLEDGEMENTS ................................................................................ ix I. OVERVIEW CHAPTER ................................................................................ 1 Falls in older adults ...................................................................................... 1 Risk Factors .............................................................................................. 1 Assessment .............................................................................................. 2 Postural balance .......................................................................................... 4 Visual system ............................................................................................ 5 Vestibular system ...................................................................................... 6 Somatosensory system ............................................................................. 6 Muscular system ....................................................................................... 7 Cognition ................................................................................................... 9 Age related changes in postural balance ................................................... 10 Sensory Impairments .............................................................................. 10 Motor impairments .................................................................................. 13 Cognition and attention deficits ............................................................... 14 Interventions for improving balance in older adults .................................... 16 Aerobic Exercise ..................................................................................... 16 Balance training ...................................................................................... 17 Tai Chi..................................................................................................... 18 Resistance training ................................................................................. 18 Cognitive training .................................................................................... 19 Whole body vibration therapy ..................................................................... 20 Effects of whole body vibrations on muscular strength ........................... 20 Effects of whole body vibrations on postural balance ............................. 22 Effects of whole body vibrations on cognitive performance ..................... 23 Segmental vibration therapy ....................................................................... 24 Rationale .................................................................................................... 25 Objectives/Hypothesis ................................................................................ 26 iii References ................................................................................................. 27 II. THE EFFECT OF SEGMENTAL VIBRATION THERAPY ON MUSCLE ACTIVITY AND BALANCE PERFORMANCE UNDER DIFFERENT SENSORY CONDITIONS. ............................................................................ 50 Introduction ................................................................................................ 50 Methods ..................................................................................................... 55 Results ....................................................................................................... 59 Discussion .................................................................................................. 71 Conclusion ................................................................................................. 74 References ................................................................................................. 76 III. THE EFFECT OF SEGMENTAL VIBRATION THERAPY ON EXECUTIVE FUNCTION. ................................................................................................... 83 Introduction ................................................................................................ 83 Methods ..................................................................................................... 85 Result ......................................................................................................... 88 Discussion .................................................................................................. 96 Conclusion ................................................................................................. 99 References ............................................................................................... 100 IV. THE EFFECT OF SEGMENTAL VIBRATION THERAPY ON DUAL TASKING POSTURAL BALANCE IN OLDER ADULTS. ............................. 104 Introduction .............................................................................................. 104 Methods ................................................................................................... 108 Results ..................................................................................................... 112 Discussion ................................................................................................ 132 Conclusion ............................................................................................... 135 References ............................................................................................... 136 V. SUMMARY CHAPTER ............................................................................ 142 References ............................................................................................... 146 APPENDICES ............................................................................................. 149 Appendix A: Effect of SVT on balance and muscle activity data tables. ... 150 Appendix B: Effect of SVT on Executive function data tables. ................. 152 Appendix C: Effect of SVT on dual-tasking postural balance data tables . 153 iv LIST OF FIGURES Figure 1. Box plot represents data for fall risk pre-post CON vs SVT. ........... 60 Figure 2. Box plot of m-CTSIB sway index scores CON vs SVT during the firm surface conditions. ......................................................................................... 62 Figure 3. Box plot of m-CTSIB sway index scores CON vs SVT during the soft surface conditions .......................................................................................... 63 Figure 4. Box-plots of soleus muscle activity CON vs SVT during the firm surface conditions. ......................................................................................... 65 Figure 5. Box-plots of soleus muscle activity CON vs SVT during the soft surface conditions. ......................................................................................... 66 Figure 6. Box-plot of lateral gastrocnemius muscle activity CON vs SVT during firm surface conditions. ....................................................................... 67 Figure 7. Box-plot of lateral gastrocnemius muscle activity CON vs SVT during soft surface conditions. ....................................................................... 68 Figure 8. Box-plot of tibialis anterior muscle activity CON vs SVT during firm surface conditions .......................................................................................... 69 Figure 9. Box-plot of tibialis anterior muscle activity CON vs SVT during soft surface conditions .......................................................................................... 70 Figure 10. Box plot represents data for attention and inhibition computed scores. ........................................................................................................... 90 Figure 11. Box plot represents data for attention and inhibition fully corrected T- scores ....................................................................................................... 91 Figure 12. Box plot represents data for working memory raw scores. ........... 92 v Figure 13. Box plot represents data for working memory fully corrected T- scores. ........................................................................................................... 93 Figure 14. Box plot represents data for processing speed raw scores. ......... 94 Figure