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

Ruth McLaren; Paul F Smith; Rachael L Taylor; Shobika Ravindran; Usman Rashid; Denise Taylor

doi:10.3389/fnins.2022.1010239

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

Front Neurosci. 2022 Sep 28:16:1010239. doi: 10.3389/fnins.2022.1010239. eCollection 2022.

Authors

Ruth McLaren¹, Paul F Smith^{2

3}, Rachael L Taylor^{3

4}, Shobika Ravindran¹, Usman Rashid¹, Denise Taylor^{1

3}

Affiliations

¹ Rehabilitation Innovation Centre, Health and Rehabilitation Research Institute, School of Clinical Science, Auckland University of Technology, Auckland, New Zealand.
² Department of Pharmacology and Toxicology, School of Biomedical Sciences, The Brain Health Research Centre, University of Otago, Dunedin, New Zealand.
³ Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand.
⁴ Department of Physiology, University of Auckland, Auckland, New Zealand.

Abstract

Objective: Noisy galvanic vestibular stimulation (nGVS) has been used to boost vestibular afferent information to the central nervous system. This has the potential to improve postural control for people for whom vestibular signals are weak, such as in bilateral vestibulopathy (BVP). The aim of this systematic review and meta-analysis is to investigate the evidence for nGVS as a modality to improve postural control in people with BVP.

Methods: A comprehensive systematic search was conducted of five databases up to July 2022 to find studies applying nGVS to people with BVP, with the aim of improving postural control. Two independent reviewers screened and identified eligible studies, completed a risk of bias evaluation (Cochrane) and extracted relevant data. The standardized mean difference (SMD) based on Hedges' g was calculated as a measure of effect size for the primary outcome measure that best identified postural control, and a forest plot generated.

Results: Seven studies met the eligibility criteria, with five being suitable for meta-analysis. Meta-analysis revealed a moderate effect in favor of nGVS improving postural control during standing and walking [pooled SMD = 0.47 95% CI (0.25, 0.7)]. nGVS-mediated improvements in postural control were most evident in observations of reduced sway velocity when standing on a firm surface with eyes closed, and in the reduced variability of gait parameters, particularly those measuring lateral stability.

Conclusions: Coincident nGVS in people with BVP improves postural control during standing and walking. This improvement appears to be context specific, in that vestibular augmentation is most effective in situations where visual inputs are limited, and where reliable context specific proprioceptive cues are available. Further research is warranted investigating additional circumstances in which nGVS improves postural control, including investigating the residual, and sustained effects of nGVS.

Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=342147, identifier: 342147.

Keywords: balance; nGVS; neuromodulation; noisy galvanic vestibular stimulation; physical therapy; vestibular rehabilitation.

Publication types

Systematic Review