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Abstract
Background. Unilateral centrifugation testing is an assessment of unilateral utricular function in which the rotary chair is laterally translated so the axis of rotation is through one utricle. Outcome parameters are the Subjective Visual Vertical (SVV) and ocular torsion.
Purpose. The purpose of the study was to examine: (a) how two different methods of lateral translation affect SVV, ocular torsion, and symptoms of nausea in a normal population; (b) the physiologic output of the utricle by comparing magnitude differences in SVV and ocular torsion as the degree of centrifugal stimulation changes in a normal population; (c) the effects of age on SVV and ocular torsion in a normal population and; (d) utricular function in individuals with a significant caloric weakness.
Study sample. Thirty one normal controls and five individuals with unilateral vestibular hypofunction participated in the study. Normal participants were characterized by having normal hearing sensitivity, no history of neurologic or balance/dizziness involvement and negative results on a direct office vestibular examination. Unilateral vestibular hypofunction was defined as an asymmetry > 30% on caloric testing.
Intervention. Unilateral centrifugation was completed at 300°/sec using various lateral translation distances.
Data collection and analysis. Non-parametric statistics were used for data analyses. Correlation analyses were completed with Spearman’s correlation. Within subjects’ comparisons were completed using Wilcoxon. Between subjects’ comparisons were completed using Mann Whitney U.
Results. There was no significant difference in ocular torsion, SVV, or level of nausea between methods of lateral translation. Systematic changes in ocular torsion and SVV occurred with changes in degree of centrifugal stimulation throughout the study. There was no significant difference in ocular torsion or SVV between age groups. One subject with unilateral vestibular hypofunction demonstrated a significantly different regression slope.
Conclusion. Either method of lateral translation effectively assesses unilateral utricular function. Age does not appear to have a significant effect on outcome parameters during unilateral centrifugation. Further investigation in diagnosing utricular dysfunction in specific patient populations is needed.
