Leftward hvHIT gain values, percentage of gain asymmetry, head velocity, RS velocity, latency, and frequency were compared between the VD and NVD groups by the Student unpaired two-tailed test or the non-parametric Mann–Whitney test. Within subjects rightward and leftward head velocities and VOR gains were compared by the Student paired two-tailed test or the non-parametric Wilcoxon matched-pairs signed-ranks test. Data sets were tested for normal distribution by the Shapiro–Wilk normality test and the appropriate statistical tests were accordingly used. Proportions of the cut-off gain values, presence of RS, detection of RS with specific velocity and frequency characteristics, and their combinations were compared between the groups employing the Fisher’s exact test. Sensitivity, specificity, positive and negative predictive values towards the prediction of VD were calculated for the various outcome measures and their combinations. P-values <0.05 were considered statistically significant. Statistical analysis was performed using the GraphPad InStat version 3.06 software (San Diego, CA, USA).