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Hoppes, Carrie W. (2017) USE OF NEAR-INFRARED SPECTROSCOPY TO EXAMINE CEREBRAL ACTIVATION DURING OPTIC FLOW. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Background: Individuals with visual vertigo describe symptoms of dizziness, disorientation, and/or impaired balance in environments with conflicting visual and vestibular information or complex visual stimuli. Physical therapists often prescribe habituation exercises using optic flow as part of a rehabilitation regimen to treat these symptoms, but there are no evidence-based guidelines for delivering optic flow. While beneficial and often prescribed, it is unclear how the brain processes the visual stimuli. Objective: The purposes of this study were to use functional near-infrared spectroscopy (fNIRS) to explore cerebral activation during varying types of optic flow and support surfaces. Design: Cross-sectional Methods: Fifteen healthy participants stood on a force plate in a virtual reality environment and viewed two types of yaw optic flow (pseudo-random and constant velocity) with or without the presence of a fixation cross while standing on a fixed surface. Thirty participants (15 patients with visual vertigo and 15 age- and gender-matched healthy controls) stood on a force plate in a virtual reality environment and viewed two types of anterior-posterior optic flow (single sine and sum of sines) while standing on a fixed or sway-referenced surface. Changes in cerebral activation were recorded from the bilateral fronto-temporo-parietal and occipital lobes using fNIRS. Results: Cerebral activation, indicated by a change in oxyhemoglobin concentration, was greater in the bilateral fronto-temporal-parietal lobes when optic flow moving unidirectionally in the yaw plane was viewed with a fixation cross. Cerebral activation was reduced in patients compared to controls in the bilateral anterior fronto-temporal regions during optic flow when standing on a fixed floor. Cerebral activation was also reduced in patients compared to controls in the right anterior fronto-temporal region during optic flow when standing on a sway-referenced floor. Conclusions: Greater cortical activation in the bilateral anterior fronto-temporal lobes of healthy adults provides preliminary support for the use of a fixation cross during habituation to optic flow. Patients with visual vertigo show less cerebral activation in regions associated with multi-sensory integration in comparison to healthy controls. This decreased activation may represent an altered ability to perform sensory re-weighting of visual information, leading to symptoms of dizziness and imbalance.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Hoppes, Carrie W.cwh27@pitt.educwh27
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee MemberFurman, Joseph
Committee MemberHuppert, Theodore
Committee MemberSparto, Patrick
Committee ChairWhitney, Susan
Date: 11 September 2017
Date Type: Publication
Defense Date: 30 June 2017
Approval Date: 11 September 2017
Submission Date: 16 December 2016
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Number of Pages: 230
Institution: University of Pittsburgh
Schools and Programs: School of Health and Rehabilitation Sciences > Rehabilitation Science
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: functional near-infrared spectroscopy, visual vertigo, optic flow, balance
Date Deposited: 11 Sep 2017 15:09
Last Modified: 11 Sep 2017 15:09


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