Subjective visual vertical test: the effect of preset angle and visual background

Document Type : Original article

Authors

1 1. MSc student in Audiology, Audiology Department, Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences. . Tehran. Iran

2 2. Instructor, MSc of Audiology, Audiology Department, Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences. Tehran. Iran

3 3. Ph.D. Candidate in Audiology, MSc of Audiology, Audiology Department, University of Social Welfare and Rehabilitation Sciences. Tehran. Iran

4 4. Associated professor of Statistics, Dept. of Basic Sciences, Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences. Tehran. Iran

Abstract

Background and Aim: Abstract Subjective Visual Vertical (SVV) test estimates mental perception of vertical orientation. Previous researches showed that individuals with normal vestibular function align the SVV line indicator within 2 degrees of true vertical (0 degrees). The aims of this study were to evaluate the effect of preset angle on SVV value in static and dynamic visual background and also to compare the effect of clockwise and counterclockwise rotation of visual background on SVV value.
Material & Method: Fifty normal adults (19 men and 31 women), with ages ranged from 18 to 40 years were asked to set a luminous bar as vertical in six different conditions: two times in static visual background condition and four times in dynamic visual background condition. Synapsys SVV instrument was used in this study.
Results: On one hand, the direction of preset angle had ipsilateral effect on deviation of SVV with static and dynamic background. It means that right preset angle made rightward deviation of SVV and left preset angle made leftward deviation of SVV (P <0.001). On the other hand, the direction of visual background rotation had significant and ipsilateral effect on SVV with dynamic background. It means clockwise rotation made rightward deviation of SVV and counterclockwise rotation made leftward deviation of SVV (P <0.001).
Conclusion: For correct interpretation and precise diagnosis of vestibular disorders using the SVV test within the vestibular test battery, we should consider the effect of preset angle and rotation of visual background on the results.

Keywords

References

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The Scientific Journal of Rehabilitation Medicine
Volume 2, Issue 2 - Serial Number 2
July and August 2013
Pages 47-54

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History

  • Receive Date: 09 June 2012
  • Revise Date: 06 August 2012
  • Accept Date: 06 November 2012
  • First Publish Date: 22 June 2013

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