Background: The otoliths act as gravito-inertial force sensors and contribute to the perception of spatial orientation. The perception of gravitational vertical can be assessed by asking a subject to adjust a light bar to the vertical. Prior to clinical use of the SVV (subjective visual vertical) test, normative data and test-retest reliability must be established.
Purpose: To obtain normative data and d etermine the test-retest reliability for the SVV test performed in static and dynamic test conditions.
Research Design: A descriptive design was used to obtain normative data.
Study Sample: Twenty-four young adults with no history of neurological disease, middle-ear pathology, open or closed head injury, cervical injury, or audiovestibular disorder participated in the study.
Data Collection and Analysis: The SVV angle was measured in the static position and in three dynamic conditions: (1) on-axis clockwise (CW) rotation, (2) off-axis CW rotation of right ear, and (3) off-axis CW rotation of left ear.
Results: In young healthy individuals, the SVV was <2° for static and on-axis rotation, and shifted up to 11° during unilateral centrifugation. Test-retest reliability of the SVV was good for all test conditions.
Conclusions: The normative data obtained in this study may be useful in identifying patients with chronic utricular dysfunction. We recommend the use of difference angles (on-axis SVV – off-axis SVV) to remove baseline bias and decrease the variability of the SVV angles for the off-axis conditions.
Key Words
Saccule and utricle - subjective visual vertical - vestibular function tests
