VISUOSPATIAL ATTENTION DURING LOCOMOTION by ON-YEE AMY LO A DISSERTATION ...

131 Pages·2015·1.35 MB·English

VISUOSPATIAL ATTENTION DURING LOCOMOTION

by

ON-YEE AMY LO

A DISSERTATION

Presented to the Department of Human Physiology
and the Graduate School of the University of Oregon
in partial fulfillment of the requirements
for the degree of
Doctor of Philosophy

December 2015
DISSERTATION APPROVAL PAGE

Student: On-Yee Amy Lo

Title: Visuospatial Attention During Locomotion

This dissertation has been accepted and approved in partial fulfillment of the
requirements for the Doctor of Philosophy degree in the Department of Human
Physiology by:

Dr. Li-Shan Chou Chairperson
Dr. Paul van Donkelaar Core Member
Dr. Anita Christie Core Member
Dr. Louis Osternig Core Member
Dr. Paul Dassonville Institutional Representative

and

Dr. Scott L. Pratt Dean of the Graduate School

Original approval signatures are on file with the University of Oregon Graduate School.

Degree awarded December 2015.
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© 2015 On-Yee Amy Lo
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DISSERTATION ABSTRACT

On-Yee Amy Lo

Doctor of Philosophy

Department of Human Physiology

December 2015

Title: Visuospatial Attention During Locomotion

Locomotion requires visuospatial attention. However, the role and cortical control
of visuospatial attention during locomotion remain unclear. Four experiments were
conducted in this study to examine the role and cortical control of visuospatial attention
during locomotion in healthy young adults. In the first experiment, we employed a
visuospatial attention task at different phases of obstacle crossing during gait. The results
suggested that toe-obstacle clearance was significantly reduced for the trailing limb when
distraction interfered with visuospatial attention during the approaching phase of obstacle
crossing. In the second experiment, subjects performed a visual Stroop task while
approaching and crossing an obstacle during gait. The results for the second experiment
indicated toe-obstacle clearance was significantly increased for the leading and trailing
limbs. Taken together, it was found that different visual attention tasks lead to distinct
modifications on obstacle crossing behaviors. In the third and fourth experiments, anodal
transcranial direct current stimulation (tDCS) was applied over the right posterior parietal
cortex (PPC) to examine the aftereffects on attention function and locomotor behavior.
The results suggested that the orienting attention was significantly improved after anodal
tDCS. In addition, the aftereffects of anodal tDCS potentially enhanced cognitive and
motor performance while interacting with a challenging obstacle-crossing task in young
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healthy adults, suggesting that the right PPC contributes to attending visuospatial
information during locomotion. This study demonstrated that visuospatial attention is
critical for planning during locomotion and the right PPC contributes to this interplay of
the neural processing of visuospatial attention during locomotion.
This dissertation includes previously published and unpublished co-authored
material.

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CURRICULUM VITAE

NAME OF AUTHOR: On-Yee Amy Lo

GRADUATE AND UNDERGRADUATE SCHOOLS ATTENDED:

University of Oregon, Eugene, Oregon
New York University, New York, New York
National Yang-Ming University, Taipei, Taiwan

DEGREES AWARDED:

Doctor of Philosophy, Human Physiology, 2015, University of Oregon
Master of Arts, Pathokinesiology, 2007, New York University
Bachelor of Science, Physical Therapy, 2004, National Yang-Ming University

AREAS OF SPECIAL INTEREST:

Visuospatial Attention
Gait Analysis
Balance Control
Motor Control
Non-invasive Brain Stimulation
Geriatric Physical Therapy
Neurologic Physical Therapy

PROFESSIONAL EXPERIENCE:

Graduate Teaching Fellow, University of Oregon, Eugene, Oregon, 2011-2015

Research Assistant, New York University, New York, New York, 2007-2011

Physical Therapist (limited permit), Victory Memorial Hospital, Brooklyn,
New York, 2007-2008

Physical Therapist, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan,
2004-2005

GRANTS, AWARDS, AND HONORS:

Travel Grant, Gait and Clinical Movement Analysis Society, 2015
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Jan Broekhoff Graduate Scholarship, University of Oregon, 2013, 2015

Ursula (Sue) Moshberger Scholarship, University of Oregon, 2014

Betty Foster McCue Graduate Scholarship, University of Oregon, 2013

Eugene & Clarissa Evonuk Memorial Graduate Fellowship in Environmental or
Stress Physiology, University of Oregon, 2013

PUBLICATIONS:

Lo, O.-Y., & Chou, L.-S. (2015) Effects of different visual attention tasks on
obstacle crossing in healthy young adults. Biomedical Engineering:
Applications, Basis and Communications. In Press.

Lo, O.-Y., van Donkelaar, P., Chou, L.-S. (2015) Distracting visuospatial
attention while approaching an obstacle reduces the toe-obstacle
clearance. Experimental Brain Research, 233(4): 1137-1144.

Tunik, E., Lo, O.-Y., Adamovich S. V. (2008) Transcranial magnetic stimulation
to the frontal operculum and supramarginal gyrus disrupts planning of
outcome-based hand-object interactions. Journal of Neuroscience, 28(53):
14422-14427.
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ACKNOWLEDGMENTS
This dissertation would not be possible without tremendous support from many
special individuals. First and foremost, I would like to express my deepest gratitude to
my advisor and committee chair Dr. Li-Shan Chou for his guidance, understanding,
mentorship and friendship during my time at the University of Oregon. I am fortunate to
have an advisor who allowed me the freedom to explore on my own and provided
disciplined guidance at the same time. I will forever cherish my experience under his
watch and continue our personal and professional relationship for years to come.
I am also thankful for the other committee members. Dr. Paul van Donkelaar has
been supportive and co-advised me throughout the progress of my dissertation study. His
scientific advice and insights are crucial to the completion of this dissertation. Dr. Anita
Christie has provided constructive suggestions and motived me to ask more questions and
seek better solutions. Dr. Louis Osternig provided helpful and valuable comments that
enhanced to the clarity and fluency of this dissertation. Dr. Paul Dassonville assisted me
in developing parts of the experimental protocol and provided insightful inputs that added
depth to this dissertation. I feel privileged to have had interacted with and learned from
each of them.
My sincere appreciation goes to my fellow graduate students in the Motion
Analysis Laboratory: Vipul Lugade, Tzurei Chen, Masahiro Fujimoto, Shiu-Ling Chiu,
Scott Breloff, Jim Becker, David Howell, Chi-Wei Chou, J. J. Hannigan, Quinn Peterson,
and Szu-Hua Chen. Their help, support, encouragements and friendships have
accompanied me throughout this journey. In addition, I would like to thank several
undergraduate students for their assistance in collecting and processing data: Kaitlyn
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Juth, Lindsay Parlee, Luyun Chen, Taylor Kay, Sandra Liu, Clark Ren, Cassidy Tang,
Deborah Wang, Elden Lai and Andrew Nguyen.
I have been extremely blessed to receive constant support, warm encouragement
and unconditional love from my family: my parents Yukkeung Lo and Chunlih Wen, my
brother David and his family, Jessica and Daniel. My direct and indirect family members
have played an essential role in my life and made me who I am today. I must also express
special thanks to Jason, a wonderful, caring and loving partner, who has been flying
monthly from Los Angeles to Eugene for the past five years. I will never forget his
dedication. Furthermore, I would like to gratefully thank my friends, especially those in
Eugene, for their camaraderie, understanding and support during these years.
Above all, I am humble to give my utmost thanks to God for His indescribable
wisdom, infinitude, faithfulness, omniscience, patience, grace and love. I acknowledge
Him for directing my path and walking through all my ups and downs.
Last, this investigation has been supported in part by the Department of Defense
(Telemedicine Advanced Technology Research Center Award No. W81XWH-11-1-0717),
the Eugene and Clarissa Evonuk Memorial Graduate Fellowship, the Betty Foster McCue
Fellowship, the Jan Broekhoff Graduate Scholarship and the Ursula (Sue) Moshberger
Scholarship.

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TABLE OF CONTENTS
Chapter Page

I. INTRODUCTION .................................................................................................... 1
Background and Significance ................................................................................ 1
Visuospatial Attention ........................................................................................... 3

Obstacle Crossing during Walking ........................................................................ 6

Cortical Control of Locomotion ............................................................................. 8

Overall Goal and Specific Aims ............................................................................ 14

Hypotheses ............................................................................................................. 15

Flow of the Dissertation ......................................................................................... 16

II. DISTRACTING VISUOSPATIAL ATTENTION WHILE APPROACHING AN
OBSTACLE REDUCES THE TOE-OBSTACLE CLEARANCE ............................. 17

Introduction ............................................................................................................ 17
Methods.................................................................................................................. 20
Subjects ............................................................................................................ 20
Visuospatial Attention Task ............................................................................. 20
Obstacle Crossing and Motion Capture System .............................................. 22
Protocol ............................................................................................................ 22
Data Analysis ................................................................................................... 23
Results .................................................................................................................... 25
Discussion .............................................................................................................. 28
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