Combining vestibular rehabilitation with noisy galvanic vestibular stimulation for treatment of bilateral vestibulopathy

Abstract

Objective Noisy galvanic vestibular stimulation (nGVS) has been shown to partly restore vestibular function and to stabilize stance and gait in patients with incomplete bilateral vestibulopathy (BVP). Here, we examined potential synergistic effects of nGVS when combined with standardized vestibular rehabilitation training (VRT). Methods 23 patients with confirmed BVP received a 30-min vestibular rehabilitation training (VRT) program three times a week for 2 weeks. The intervention group (n = 12) was stimulated with nGVS (at individually determined optimal amplitudes) during training, whereas the control group (n = 11) received zero-amplitude nGVS (sham stimulation) during training. Outcome measurements assessed at baseline, after 2 weeks of training, and at 2-week follow-up included quantitative posturography, instrumented gait analysis, Timed Up and Go Test (TUG), Functional Gait Assessment (FGA), and clinical scores related to quality of life and balance confidence. Results After 2 weeks of VRT, all patients showed moderate improvement in balance. Irrespective of nGVS treatment, performance improved in the TUG (p < 0.013), and in the FGA (p < 0.040). Furthermore, base of support when walking with closed eyes was reduced after 2-week training (p < 0.003). Postural sway did not change. There was no difference between groups and thereby no evidence for an additional influence of nGVS on the VRT treatment effects. Conclusion nGVS does not induce synergistic treatment effects in combination with VRT in patients with BVP when applied during treatment sessions. Hence, rather than being applied in parallel, nGVS and VRT might be complementary therapeutic options with nGVS being used during postural activities in daily life, e.g., walking.

Efficacy of nGVS to improve postural stability in people with bilateral vestibulopathy: A systematic review and meta-analysis

“…The meta-analysis was performed on these five studies. One study used a pre/post experimental design and assessed the post-stimulation effects of nGVS on postural control (Fujimoto et al, 2018 ) and one was a randomized controlled pilot study (Eder et al, 2022 ). Six studies explored the efficacy of a single session of nGVS (Iwasaki et al, 2014 , 2018 ; Wuehr et al, 2016a ; Fujimoto et al, 2018 ; Sprenger et al, 2020 ; Chen et al, 2021 ).…”

“…Six studies explored the efficacy of a single session of nGVS (Iwasaki et al, 2014 , 2018 ; Wuehr et al, 2016a ; Fujimoto et al, 2018 ; Sprenger et al, 2020 ; Chen et al, 2021 ). One study evaluated the cumulative effect of multiple sessions of nGVS combined with vestibular rehabilitation (Eder et al, 2022 ). All studies utilized some method of determining the optimum amplitude of nGVS ( Table 4 ).…”

“…In the only study to report the effects of nGVS-augmented rehabilitation, Eder et al ( 2022 ) reported that 6 sessions of nGVS over 2 weeks together with vestibular rehabilitation did not significantly reduce postural sway in people with BVP. There was no difference in postural control measures between the experimental group receiving nGVS plus vestibular rehabilitation and the control group receiving sham nGVS plus vestibular rehabilitation (Eder et al, 2022 ).…”

“…While there is good evidence for the immediate benefit of nGVS to improve postural stability during standing and walking with some residual effect following the removal of the stimulation, there has been speculation about the effect of nGVS as an adjunct to rehabilitation (Iwasaki et al, 2014 ; Chen et al, 2021 ; Lotfi et al, 2021 ). Eder et al ( 2022 ) piloted nGVS as an adjunct to vestibular rehabilitation in people with BVP for 30 mins three times a week for 2 weeks. They found that vestibular rehabilitation for 2 weeks yielded moderate improvements in functional mobility as measured by the timed up and go, and functional gait analysis, but found no significant difference between the nGVS and sham group on any outcome measures.…”

Enhancement of vestibular motion discrimination by small stochastic whole-body perturbations in young healthy humans

“…The evidence we provided that small-amplitude motion perturbations can enhance the perceptual discrimination of motion direction has potential implications for both physiology and medicine. From a physiological standpoint, our results suggest the possibility that, just as the external noise that we applied, also the spontaneous random oscillations of the body associated with posture (Duarte and Zatsiorsky 2000) are beneficial by enhancing vestibular thresholds with a mechanism similar to SR. From a clinical standpoint, there is the possibility that the application of small-amplitude motion perturbations can be a useful rehabilitation tool for individuals with elevated thresholds for vestibular motion perception, such as people with vestibulopathy (Eder et al 2022), vestibular hypofunction (Priesol et al 2014) or the elderly (Bermudez et al 2016). In this respect, it remains to be seen whether noise such as that we applied here can improve not just vestibular perception, but also vestibulo-spinal function for balance control.…”