Post-hoc sensitivity analyses for non-response bias and attrition
To assess non-response bias and attrition the authors conducted several sensitivity analyses. The baseline characteristics for participants who filled in the 36-month follow-up and those who did not are described separately in Supplementary Table S3. Participants who completed 36-month follow-up had a relatively higher level of education, were less likely to live alone, and more often followed the per-protocol treatment. The results of a subsequent complete case sensitivity analysis, where only the patients who filled in the 36-month were included, showed similar results to the primary analysis (Supplementary Table S4). Lastly, a per-protocol analysis with participants who filled in the 36-month follow-up showed that VR participants who followed all sessions had fewer vestibular symptoms at long-term follow-up, indicating a positive effect of better engagement (Supplementary Table S5).