The long-term goal of this project is to understand how balance and gait disorders can be helped by using dynamic visual environments to facilitate sensorimotor relearning during locomotion and stance postural control. When vestibular inputs become unreliable, either from labyrinthine loss or dysfunction, individuals must learn to rely upon visual and proprioceptive pathways to produce appropriate responses for changes in postural orientation or equilibrium. Attempts to produce sensory relearning through practicing postural and purposeful activities in static environments have not proved to be a fully successful intervention, possibly because the controlled inputs do not place the necessary demands on the functionality of the postural system. Individuals may become fixed on one pattem of response and be unable to match the range of disturbances encountered in the environment. We propose to study changes in postural responses and spatial orientation during locomotion within a dynamic visual environment in normal subjects and in patients with bilateral labyrinthine loss. We hypothesize that individuals _ with vestibular loss become fixed on one strategy of compensation and can not compensate for the fluctuating demands of a dynamic environment. We will examine whether providing strategies for using visual information assists these individuals in compensating for destabilization. Subjects will be tested during quiet stance and walking on a treadmill while we manipulate the velocity or contextual contrast of a dynamic virtual environment. Segmental excursions and center of pressure will be measured and analyzed with repeated measures ANOVAs to determine if postural organization and orientation is influenced by specific parameters of the peripheral field of view. The parameters that emerge as most destabilizing will be applied in a training program where subjects will be instructed to focus on a distant target or on internal feedback to determine if active performance in a dynamic visual environment increases the response repertoire of individuals with labyrinthine loss. Finally, we will assess whether there is functional carryover from training within a dynamic visual environment. Subjects will perform a simulated physical world task in which they must retrieve and place an object while the world moves around them and obstacles appear in their path. Results from these studies will provide insight into the dynamics of the visual- vestibular interaction and identify specific quantitative protocols for therapeutic interventions with balance disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
7R01DC005235-05
Application #
7162947
Study Section
Special Emphasis Panel (ZRG1-BBBP-7 (01))
Program Officer
Sklare, Dan
Project Start
2003-01-13
Project End
2008-12-31
Budget Start
2007-01-01
Budget End
2008-12-31
Support Year
5
Fiscal Year
2007
Total Cost
$317,155
Indirect Cost
Name
Temple University
Department
Physiology
Type
Schools of Medicine
DUNS #
057123192
City
Philadelphia
State
PA
Country
United States
Zip Code
19122
Haran, F J; Tierney, R; Wright, W G et al. (2013) Acute changes in postural control after soccer heading. Int J Sports Med 34:350-4
Slaboda, Jill C; Lauer, Richard T; Keshner, Emily A (2011) Continuous visual field motion impacts the postural responses of older and younger women during and after support surface tilt. Exp Brain Res 211:87-96
Slaboda, Jill C; Lauer, Richard; Keshner, Emily A (2011) Time series analysis of postural responses to combined visual pitch and support surface tilt. Neurosci Lett 491:138-42
Wang, Yun; Kenyon, Robert V; Keshner, Emily A (2010) Identifying the control of physically and perceptually evoked sway responses with coincident visual scene velocities and tilt of the base of support. Exp Brain Res 201:663-72
Dokka, Kalpana; Kenyon, Robert V; Keshner, Emily A et al. (2010) Self versus environment motion in postural control. PLoS Comput Biol 6:e1000680
Keshner, Emily A; Kenyon, Robert V (2009) Postural and spatial orientation driven by virtual reality. Stud Health Technol Inform 145:209-28
Dokka, Kalpana; Kenyon, Robert V; Keshner, Emily A (2009) Influence of visual scene velocity on segmental kinematics during stance. Gait Posture 30:211-6
Slaboda, J C; Barton, J E; Maitin, I B et al. (2009) Visual field dependence influences balance in patients with stroke. Conf Proc IEEE Eng Med Biol Soc 2009:1147-50
Dvorkin, Assaf Y; Kenyon, Robert V; Keshner, Emily A (2009) Effects of roll visual motion on online control of arm movement: reaching within a dynamic virtual environment. Exp Brain Res 193:95-107
Keshner, E A; Dhaher, Y (2008) Characterizing head motion in three planes during combined visual and base of support disturbances in healthy and visually sensitive subjects. Gait Posture 28:127-34

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