Hoppes, Carrie W.
(2017)
USE OF NEAR-INFRARED SPECTROSCOPY TO EXAMINE CEREBRAL ACTIVATION DURING OPTIC FLOW.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
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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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| 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 2022 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/30598 |
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