Noisy vestibular stimulation improves vestibulospinal function in patients with bilateral vestibulopathy

Abstract

The present findings allow to identify the mechanism by which nGVS appears to stabilize stance and gait performance in patients with BVP. Accordingly, nGVS effectively lowers the vestibular threshold to elicit balance-related reflexes that are required to adequately regulate postural equilibrium. This intervention is only effective in the presence of a residual vestibular functionality, which, however, applies for the majority of patients with BVP. Low-intensity noise stimulation thereby provides a non-invasive treatment option to optimize residual vestibular resources in BVP.

No evidence for after-effects of noisy galvanic vestibular stimulation on motion perception

“…The rationale behind this phenomenon is a mechanism known as stochastic resonance (SR), according to which the response of a non-linear system to weak input signals can be optimized by the presence of a particular level of stochastic interference, i.e., noise 5,6 . SR-like phenomena in the vestibular system can be induced by an imperceptible noisy galvanic vestibular stimulation (nGVS), which was shown to effectively lower thresholds for vestibular motion perception and vestibulospinal reflexes [7][8][9][10][11] . The therapeutic potential of nGVS was further explored in patients with vestibular hypofunction that suffer from pathologically increased thresholds for vestibular information processing 12,13 .…”

Finding a Balance: A Systematic Review of the Biomechanical Effects of Vestibular Prostheses on Stability in Humans

“…Most commonly, this was VOR restoration (for vestibular implants) and postural sway (for nGVS) (Tables 2 and 3). Improvements in dynamic visual acuity, postural sway control, vestibulospinal function and gait speed were also shown to improve after vestibular stimulation [14,31,40,44]. Moreover, a randomised control trial showed improved balance control was also reported in healthy patients after nGVS [39].…”

“…It has also been demonstrated that using different configurations of stimuli can assist balance in both the sagittal and frontal planes [30]. However, the mechanism of nGVS means that patients with no residual vestibular function, although few in number, would fail to benefit from this treatment [31].…”

“…A total of 11 studies investigated the use of GVS to modulate vestibular function [16,[25][26][27][28]31,[38][39][40][41][42]. Only five of these were conducted on participants with BVD, with the rest conducted on healthy patients.…”

“…This study was a single-arm trial and it is possible that the subjective improvement scores were attributable to the placebo effect. However, significant improvement in postural control due to stimulation extended well beyond 2 h. A total of seven papers allowed a time period of under 10 min to 'recover from the effect of nGVS' [16,27,31,[38][39][40][41]. The findings of Uemura and Fujimoto call into question the methodological validity of these trials, as they proved it can take far longer for the effects to subside.…”