The purpose of this study was to examine the mechanisms of adaptation and substitution through vHIT in patients with UVD who underwent vestibular rehabilitation over time.
The subjects were patients who received vestibular rehabilitation at our dizziness center (VR group) and patients who were followed up without vestibular rehabilitation (control group). The VR group participated in weekly vestibular rehabilitation sessions for six months. Both groups were assessed using vHIT prior to observation and at 6 and 12 months following the commencement of observation. The vHIT was conducted using the EyeSeeCam system (Interacoustics, Denmark). Subjects, seated and wearing goggles, were passively rotated by the examiner, moving their heads rapidly from side to side while maintaining focus on a target placed one meter ahead. The vHIT measured 15 left and 15 right head rotations to calculate gain and CUS latency.
Statistical analysis was performed using a two-way analysis of variance to determine differences in gain between the two groups at baseline and at six and 12 months, with Bonferroni post hoc tests. In the VR group, cases with a VOR gain of less than 0.8 after 12 months were further analyzed for differences in CUS latency, using paired t-tests. The significance level for all statistical tests was set at 5%.
There were 16 patients in the VR group and 13 patients in the control group. A significant time factor and interaction effect were observed for the affected side’s VOR gain. Post hoc tests revealed significant increases in gain only in the VR group between baseline and six months and between baseline and 12 months. In the VR group, patients with limited gain improvement showed shorter CUS latency at 12 months compared to baseline.
The study's findings suggest that vestibular rehabilitation improves gain and reduces CUS latency in UVD patients. These improvements correspond to the mechanisms of adaptation (increase in gain) and substitution (reduction in CUS latency). However, given that the hair cells in the semicircular canals lack regenerative capacity, the ability for adaptation is limited. Therefore, substitution through compensatory functions becomes essential for recovery in these patients. The results support vestibular rehabilitation as an effective intervention for improving vestibular function in UVD patients by promoting these adaptive and compensatory mechanisms.
The findings of this study enable the quantification of the mechanisms underlying vestibular rehabilitation and suggest that vHIT serves as a reliable indicator of improvement in patients with UVD.
video head impulse test
peripheral vestibular dysfunction
