Gaze stabilization test (GST) and dynamic visual acuity (DVA) test are functional measures of the vestibulo-ocular reflex which helps to maintain clear vision during head movement. The purposes of this dissertation were threefold; first the reliability of GST and DVA test were examined. Twenty-nine patients with vestibular disease were tested repeatedly using the computerized InVision™ test. Results showed that the reliability of the tests were fair to poor with the DVA reliability better than the GST and the within-session reliability better than between-session reliability. In the second Aim, the goal was to obtain better understanding of the effect of optotype (the letter E) parameters on subjects' performance. The performance of twenty-one healthy young subjects on the GST was examined over a range of optotype sizes and presentation times. Results showed that the optotype parameters had a significant effect on subjects' performance with only one combination in which most healthy subjects were able to accomplish fast head velocities while being able to identify the optotype correctly. An optotype that is 0.30 logMAR above a subject's static vision and presented for 40 msec longer than minimum presentation time is recommended for future testing. Lastly, the preferred combination from the second Aim was used to examine the performance of twenty-two young patients following concussion and compare it with the healthy subjects from Aim 2. Correlations between patients' performance on the GST and their scores on tests commonly used following concussion were also examined. Results showed no significant differences between the performance of patients and that of healthy subjects on the GST. Also, there were no significant correlations between the GST and other measures used following concussion. Results show that the protocol used for the GST needed refinement. Special consideration is to be given to the optotype parameters used since these were found to significantly influence performance. The lack of significant differences between patients following concussion and healthy subjects could be due to the inclusion of all patients following concussion without objective evidence of vestibular involvement. Future studies should use specific optotype parameters and include patients following concussion with evidence of vestibular dysfunction.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04252011-151545 |
| Date | 10 May 2011 |
| Creators | mohammad, maha |
| Contributors | Susan Whitney, Patrick Sparto, Gregory Marchetti, Joseph Furman |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04252011-151545/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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