Greater functional activation during galvanic vestibular stimulation is associated with improved postural stability: a GVS-fMRI study

Abstract

Purpose

Previous literature has shown that standing stability relies on the vestibular system; however, the neural correlates underlying standing stability remains unclear. This study aimed to investigate the neural correlates of standing stability using functional magnetic resonance imaging (fMRI) following galvanic vestibular stimulation (GVS).

Materials and methods

Forty-five healthy right-handed healthy volunteers were included. Postural stability was measured using the modified Clinical Test of Sensory Interaction and Balance (mCTSIB), which measures swaying speed and area on hard and soft surfaces when the volunteer’s eyes are open and closed. Functional activation as determined by the blood oxygenation level-dependent (BOLD) response, was measured during GVS using fMRI. We investigated the association between BOLD responses during GVS and postural stability.

Results

Relative to rest, participants showed significantly higher BOLD signal during GVS in the parietal operculum, central operculum, and the opercular part of the inferior frontal gyrus. Moreover, functional activation in the central operculum was negatively correlated with standing stability, indexed using swaying speed when volunteers stood on a foam surface with their eyes closed.

Conclusions

Our findings suggest that the neural correlates of standing stability involve greater functional activation in the central operculum.

Keywords:

• Functional magnetic resonance imaging
• galvanic vestibular stimulation
• brain activation
• modified clinical test of sensory interaction and balance
• vestibular system
• standing postural stability

Acknowledgements

The authors thank Mr. Takahiro Kuhara and Mr. Yuji Chyuda for their help in preparing the manuscript. The authors also thank the subject for his time and effort

Disclosure statement

There are no conflicts of interest. Research involving Human Participants and/or Animals All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Numbers 17K13055, and by Takeda Science Foundation.