Unpacking Galvanic Vestibular Stimulation using simulations and relating current flow to reported motions: Comparison across common and specialized electrode placements.

Autor: Truong DQ; Research and Development, Soterix Medical, Woodbridge, New Jersey, United States of America., Thomas C; Research and Development, Soterix Medical, Woodbridge, New Jersey, United States of America., Ira S; Research and Development, Soterix Medical, Woodbridge, New Jersey, United States of America., Valter Y; Research and Development, Soterix Medical, Woodbridge, New Jersey, United States of America., Clark TK; Smead Aerospace Engineering Sciences Department, College of Engineering and Applied Science, University of Colorado, Boulder, Colorado, United States of America., Datta A; Research and Development, Soterix Medical, Woodbridge, New Jersey, United States of America.; Biomedical Engineering, City College of New York, New York, New York, United States of America.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2024 Aug 26; Vol. 19 (8), pp. e0309007. Date of Electronic Publication: 2024 Aug 26 (Print Publication: 2024).
DOI: 10.1371/journal.pone.0309007
Abstrakt: Background: Galvanic Vestibular Stimulation (GVS) is a non-invasive electrical stimulation technique that is typically used to probe the vestibular system. When using direct current or very low frequency sine, GVS causes postural sway or perception of illusory (virtual) motions. GVS is commonly delivered using two electrodes placed at the mastoids, however, placements involving additional electrodes / locations have been employed. Our objective was to systematically evaluate all known GVS electrode placements, compare induced current flow, and how it relates to the archetypal sway and virtual motions. The ultimate goal is to help users in having a better understanding of the effects of different placements.
Methods: We simulated seven GVS electrode placements with same total injected current using an ultra-high resolution model. Induced electric field (EF) patterns at the cortical and the level of vestibular organs (left and right) were determined. A range of current flow metrics including potential factors such as inter-electrode separation, percentage of current entering the cranial cavity, and symmetricity were calculated. Finally, we relate current flow to reported GVS motions.
Results: As expected, current flow patterns are electrode placement specific. Placements with two electrodes generally result in higher EF magnitude. Placements with four electrodes result in lower percentage of current entering the cranial cavity. Symmetric placements do not result in similar EF values in the left and the right organs respectively- highlighting inherent anatomical asymmetry of the human head. Asymmetric placements were found to induce as much as ~3-fold higher EF in one organ over the other. The percentage of current entering the cranial cavity varies between ~15% and ~40% depending on the placement.
Conclusions: We expect our study to advance understanding of GVS and provide insight on probable mechanism of action of a certain electrode placement choice. The dataset generated across several metrics will support hypothesis testing relating empirical outcomes to current flow patterns. Further, the differences in current flow will guide stimulation strategy (what placement and how much scalp current to use) and facilitate a quantitatively informed rational / optimal decision.
Competing Interests: DQT, CT, SI, YV, and AD are employees of Soterix Medical. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
(Copyright: © 2024 Truong et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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