Validity and reliability of the mobile virtual reality subjective visual vertical measurement system: Comparison with conventional bucket test

Background Subjective visual vertical (SVV) test is a key functional assessment tool that provides insights into vestibular imbalance. Mobile virtual reality SVV measurement system (MVR-SVV) has the potential to facilitate simple, low-cost, and reliable measurements. Objective This study aimed to verify the reliability and validity of MVR-SVV by comparing its data with the previously established bucket test (bucket-SVV). Methods Thirty-eight healthy adults completed both bucket-SVV and MVR-SVV tests. The reliability and validity of MVR-SVV were examined using intraclass correlation coefficients (ICCs), Pearson’s correlation, Bland-Altman plots (BAP), and minimum detectable change (MDC). Results BAP results indicated that the limits of agreement for the SVV angles were 1.61 to −1.24°. No fixed errors were identified ( p = 0.13), although a small proportional error was detected (y = −0.59x + 0.157, p < 0.001). Pearson’s correlation coefficient between bucket-SVV and MVR-SVV was 0.716 ( p < 0.001). Within-day reliability was poor for bucket-SVV, with ICC = 0.33–0.38, but moderate for MVR-SVV, with ICC = 0.70–0.71. Between-day reliability was poor for both methods, with ICC = 0.38 for MVR-SVV and ICC = 0.28 for bucket-SVV. MDC was 1.78° for bucket-SVV and 2.67° for MVR-SVV. Conclusions Our findings suggest that MVR-SVV can be used for assessing SVV. Its portability, availability, and reliability make it a valuable tool for clinicians in clinical settings.