Methods for Testing the Subjective Visual Vertical during the Chronic Phase of Menière's Disease.

The subjective visual vertical (SVV) evaluates the function of the utricle, which, in patients with Menière's disease (MD), can be affected by endolymphatic hydrops. This study aimed to determine the SVV in MD patients during the chronic phase of illness compared to healthy participants. The second aim was to compare the SVV measurement tools: the analog bucket test, digital bucket test, and C-SVV© goggles. The SVV scores differed significantly between MD patients and the control group for the analog bucket test (p < 0.001) and the C-SVV® goggles (p = 0.028), but no significance was shown when using the digital bucket test (p = 0.062). When comparing the analog bucket test and the C-SVV® goggles applying the calculated threshold (1.125° in analog bucket test, 2.5° in C-SVV® goggles), the bucket test showed higher accuracy (bucket test 73.84%, C-SVV® goggles 69.23%). When examining the influence of betahistine on SVV scores, there were no statistically significant differences in both the analog bucket test and C-SVV© goggles. We conclude that SVV test can be used as an additional tool to evaluate utricle function during the chronic phase of MD and that the analog bucket test produces the most reliable results. The intake of betahistine does not influence the perception of SVV.