University of the Pacific Scholarly Commons University of the Pacific Theses and Dissertations Graduate School 1976 The Training Of Human Voluntary Torsion: Tonic And Dynamic Cycloversion. Richard Balliet University of the Pacific Follow this and additional works at: https://scholarlycommons.pacific.edu/uop_etds Recommended Citation Balliet, Richard. (1976). The Training Of Human Voluntary Torsion: Tonic And Dynamic Cycloversion.. University of the Pacific, Dissertation. https://scholarlycommons.pacific.edu/uop_etds/2998 This Dissertation is brought to you for free and open access by the Graduate School at Scholarly Commons. It has been accepted for inclusion in University of the Pacific Theses and Dissertations by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. THE THAINING OF HUMAN VOLUNTARY TORSION: TONIC AND DYNAMIC CYCLOVERSION By Richard'Balliet ~-------- A dissertation in partial fulfi~lment of the requir~­ ments for the degree o~ Doctor of Philosophy presented to the Graduite Faculty of the Department of Visual Sciences of tho University of the Pacific. - ~ --------- September, l~Y16 p--- ~--- This dissertation, written and submitted by I • RICHARD_ BALLIET is approved for recommendation to the Committee @n Graduate Studies, University of the Pacific Dean of the School or Department Chairmari: Dissertation Committee: -----Chainnru1 Ucu-< ··. ~. Dated-.Septe~ 1-3, J 976 ~·---- Til!': TRAINING OF !i1J:1~.N VOLUNTARY TORSION: '!'ONIG .<\!lfl f>YNAHIC CYC!"OVERSION Abstract of the D~ssertation Torsion is clcfin.-~d as any rotation f'.rour.d the vis~al axis o~ the eyt. ~ince t.hr. middle of the 19th century some t·csearc.hers have doubted that: functionlll ocular torsions occur in man. nesearcher!; who have reported torsional eye nwvements found that these movemc.nts were either <:ontrolled _rcfle~i:'L.!llYo as ·in the counter-rolling of the eyes during lateral head tiit, or visually induced, a5 in largr; f'Leld rotary-nystagamus. It has never been found that ocular torsion could be controlled vo!~!!l.i.U• It was my conviction that the htunan oculomotor system is more plastic th<>t'. th~! e>eisting ~orsional data suggests. 1 felt that by oomploying optimal stitnulu's-response conditions voluntary torsion could be> trained, Using a visual bi.ofee:!back techni.que 3 subjects (2 normals, 1 unilateral inter­ mittant exotrope) were trained to make accurate voluntary tonic cycloversions up to 26.5 degrees in magnitude. Tonic ~ycloversion~ were defined as cycle­ versions which could be sustained for a 5 second duration. Two subjects (1 normal, 1 unibteral inter1nittailt exotrope) were further trained to raake ~ynnrnic cycloversions up to 30 degrec.s in magni.tude. Sim:l.l<~r to voluntary horizontal versions the voluntary cycluv~rsianal slow pursuit of a (rotating) objr,ct increased ~<ith the amount of visual feedback. Subjects' abilities ro p•rform voluntary cyclotorsional saccadic tracking of rotating stimuli further demonstrated dynamic cycloversions. Gyclotorsional saccadic magnitude vs. p•ak velocity relationships corresponded to those of horizontal saccades. Towards the end of traini.ng subject~ were able to l!'ake voluntary <".yclover£ions in the abs~nce of any visual stimulus, In all tests where rotating visual stimuli were used voluntary cyclover~ions were not found to be significantlv visually induced. All voluntary eye lovers ions were sho·.m t.o be pure cy.clo~ versions around the ''isual axes. In swnmary, these results suggest that existing slcilv pursu:l:t and saccadic systems control trained voluntary cyc:loversions. I propose that in making voluntary cycloversions, th~ visuomotor system, theoretically, utilizes primitive slow phase and f~st flicks from the phy~ogenetic.ally old vestibulo­ ocular i.lotor ref1ex apparatus in a manner similar to the way the voluntilry horizontal and ve1·cical slow pursuit version.~l eye movement system utilizes this control apparatus. It is possible that this type of visuomotor reorgani­ zation may not ·be limited tr, just the new voluntary cycloversional eve move· menta reported in this thesis. ;;::;-:- ----------:-:- ~~--=-----=== ACKNOWLEDGEMENTS Without Matthew Noble arid Candus Hedberg this research would not hiwe been initiated or completed. Words cannot express my ~ppreciation to them ... I wish to thank Ken Nakayam~. Paul Bach-Y-Rita and 'l'ony Adams for pulling me out of the "fire'', thus, enabling me to begin this research. I wish to thank the.following people who gave assistance and encouragement: Bob Bowen, Al Alden, Ron Wizelman, and Jules Madey. My great appreciation goes to Brian Brown for hj.s careful. editing of this dissertation. Finally, I wish to think the Smith-Kettlewell Eye Research Foundation for their financial.support over the years. This research was supported by a National Institute of Health Grant, EYO 1582, and was conducted in the joint facilitiesof the Smith..:..Kettlewell Institute of Visuar·scienees and the bepartment of Visual Scienc0s,. University of the Pacific. b- ~-' '------ -.-- ~ i. 'l'ABLE OF CONTENTS Page ACKNOWLEDGEMENTS ........•••.•.•.•......••.•..••••••.. ~ ... i LIST OF FIGURES ...•..•.........••.. ~ •.•.•..........•.. ; . vi SECTION I. TONIC CYCLOVERSIQN,.: ••. ~ •..••••...•••.......•• 1 A. II1tl"od·uction ........... ~ ....................... 1 B. .Met hod ..................... ·..................... 3 1. Subjects ..................... ; ............. _.3 2. Training and Testing Procedure .............. 4 3. Subjective Testing Measurement ........... ~ .. 6 4. Objective Testing Measurement ............. i.6 C" ResuJ_ tE~ ............................................... 8 1. Experiment 1(a): The Training of Voluntary Tonic Cyclotorsion ................ 8 2. Experiment 1(b): The Accuracy of . Subjective Tonic Torsion ....... ; ............ 9 3. ExperimBnt 2: The Apparent Difficulty of Tonic Torsion ...... : ......... 12 4. Experiment 3: Test for VoJ.untary ·cycloversion ............................... 14 5. Experiment 4: Test for Pure-Wheel Rotation During Voluntary Tonic Cycloversion .................... .- ........... 15 6. Expe~iment 5: Control Test for Visual Induction of Tonic Cyclotorsion ..... 16 --- --------- -- ~ D. Discussion; .. ~ .... t'., •••• , ••..• ~-· .- •.· ••.•••••.• 918 a;· ___ --- c" ,- ----------- ;.;;.~-~----.------~- iii TABLE OF CONTENTS (continued) ,.t·--: ~-- w Page li P__ _ R ~-- SECTION II. DYNAMIC CYCLOVERSiON .................· ... ~ .. 22 ----- -- ----- A. Introduction·.~ ...... -. ·.· .....· ........... ·........ ; .. 22 B~ Method ..................·.~ ........... -.. ··.......... 2·3 1. Subjects ............. -.-~.- .................... 23 2. General Training and Testing Procedure .......................· ........... 24 3. Testing Analysis ........................... 26 C. Resu.l t s ..... ; ... ; ~ -~ ·............... , ............ 28 1. Experiment 1(~): Voluntary Cycle­ torsional Slow Pursuit: Complete Visual Feed hack ............................ 28 2. Experiment l(b): Voluntary Cyclo­ torsional.Slow Pursuit: Partial Visual Feedback ........... ; ................ 29 3. Experiment l(c): Voluntary Cyclq­ torsional Slo~ Pursuit: No Visual ·Feedback .....· .. -.......... ·.................... 30 4. Summary of Voluntary Cyclotorsional Slow Pursuit Experiments l(a), (b), and (c)_ .....•- •.•.....••..•.•..............• 31 5, Experiment 2: Voluntary Cycle- torsional Saccadic Tracking., .............. 32 6, -Summary of ·voluntary Cyclotorsional. Saccadic Tracking: ·Magnitude vs. Peak Velocity ............ ·........ -.......... 34 7-.· Experiment 3: 'tests for Pure-­ Wheel Cycloversion During Voluntary - Dynamic Cyclotorsion ........•..... , ... ~ .... 35 ·_ '"'~--~' -.-_--,~~ ~ ---- -- iv TABLE OF CONTENTS (continued) F-------~ .,: k C. Results (continued) 8. Experi~ent 4: _ Contr61 Test for Visual Induction of Dynamic Cyclotorsion ....-. _..... -~ ............ ·......... 37 D. Discussion .................. -............... ·..... 38 1. Sl6w Pursuit and Saccadic Tracking Data .......· .... 0 .............................. 38 2. rheoretical Implications of Slow Pursuit and Saccadic Tracking Data ......... 40 · 3. Visuomotor Plasticity ......... ~· ...... ~ ..•. 41 4. Limits of Voluntary Dynamic Cycle- versions . .... ··-· .... •· ........ e .•••••••••••••.• 42 FIGURl~S . ................ ~ .............. , .................. 44 l3IBLIOGRAPHY ...._ ......... .- ........... , . ~- .... , ...... _..... 99 . 'f.,T LIST OF FIGURES F-:N-------- Figure Page 1 Representation of the monociular stimulus -- -- -- situation used in the ·training of.volun- f_.::i tary tonic cyclotorsion .......................... ~ ... 45 2 Photos 6f a tonic voluntary cyclotorsional eye movement of 20 degrees .................... ~· ..... 47 3 The training of voluntary tonic cyclotorsion for subjects C.H. and R.B ............................ 49 4 The accuracy of subjective matches compared to objective measures of voluntary tonic cyclotorsion for R.B. at 35 hours of training ........ 51 f) The accurn.cy of subjective matches compared to objective measures of voluntary tonic cyclotorsi0n for subject C.H. at 16, 25 and 35 hours of training ................................. 53 6 The accuracy of subjective matches compared to objective measures of voluntary tonic cyclotorsion for subject M.N ......................... 55 7 The subjective difficulty of voluntary tonic torsion over time .................................... 57 8 Objectively measured test for cycloversion during monocular