The effects of stochastic galvanic vestibular stimulation on human postural sway

Galvanic vestibular stimulation (GVS) is a technique in which small currents are delivered transcutaneously to the afferent nerve endings of the vestibular system through electrodes placed over the mastoid bones. The applied current alters the firing rates of the peripheral vestibular afferents, causing a shift in a standing subject's vestibular perception and a corresponding postural sway. Previously, we showed that in subjects who are facing forward, stochastic bipolar binaural GVS leads to coherent stochastic mediolateral postural sway. The goal of this pilot study was to extend that work and to test the hypothesis that in subjects who are facing forward, stochastic monopolar binaural GVS leads to coherent stochastic anteroposterior postural sway. Stochastic monopolar binaural GVS was applied to ten healthy young subjects. Twenty-four trials, each containing a different galvanic input stimulus from among eight different frequency ranges, were conducted on each subject. Postural sway was evaluated through analysis of the center-of-pressure (COP) displacements under each subject's feet. Spectral analysis was performed on the galvanic stimuli and the COP displacement time series to calculate the coherence spectra. Significant coherence was found between the galvanic input signal and the anteroposterior COP displacement in some of the trials (i.e., at least one) in nine of the ten subjects. In general, the coherence values were highest for the mid-range frequencies that were tested, and lowest for the low- and high-range frequencies. However, the coherence values we obtained were lower than those we previously reported for stochastic bipolar binaural GVS and mediolateral sway. These differences may be due to fundamental characteristics of the vestibular system such as lower sensitivity to symmetric changes in afferent firing dynamics, and/or differences between the biomechanics of anteroposterior and mediolateral sway.

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Comparison of verticality perception and postural sway induced by double temple-mastoidal and bipolar binaural 20 Hz sinusoidal galvanic vestibular stimulation

Journal of Vestibular Research ◽

10.3233/ves-210112 ◽

2021 ◽

pp. 1-15

Author(s):

Samar Babaee ◽

Moslem Shaabani ◽

Mohsen Vahedi

Keyword(s):

Postural Sway ◽

Maximum Amplitude ◽

Semicircular Canals ◽

Vestibular Stimulation ◽

Galvanic Vestibular Stimulation ◽

The Body ◽

Body Sway ◽

Mean Values ◽

Amplitude Change ◽

Threshold Levels

BACKGROUND: Galvanic vestibular stimulation (GVS) is believed to be one of the most valuable tools for studying the vestibular system. In our opinion, its combined effect on posture and perception needs to be examined more. OBJECTIVE: The present study was conducted to investigate the effect of a 20 Hz sinusoidal Galvanic Vestibular Stimulation (sGVS) on the body sway and subjective visual vertical (SVV) deviation through two sets of electrode montages (bipolar binaural and double temple-mastoidal stimulation) during a three-stage experiment (baseline, threshold, and supra-threshold levels). METHODS: While the individuals (32 normal individuals, 10 males, the mean age of 25.37±3.00 years) were standing on a posturography device and SVV goggles were put on, the parameters of the body sway and SVV deviation were measured simultaneously. Following the baseline stage (measuring without stimulation), the parameters were investigated during the threshold and supra-threshold stages (1 mA above the threshold) for 20 seconds. This was done separately for each electrode montage. Then, the results were compared between the three experimental stages and the two electrode montages. RESULTS: In both electrode montages, “the maximum amplitude” of the mediolateral (ML) and anteroposterior (AP) body sway decreased and increased in the threshold and supra-threshold stages, respectively, compared to the baseline stage. Comparison of the amount of “amplitude change” caused by each electrode montages showed that the double temple-mastoidal stimulation induced a significantly greater amplitude change in body sway during both threshold and supra-threshold stages (relative to the baseline stage). The absolute mean values of the SVV deviation were significantly different between the baseline and supra-threshold levels in both electrode montages. The SVV deviation in double temple-mastoidal stimulation was a bit greater than that in the bipolar binaural stimulation. CONCLUSION: Double temple-mastoidal stimulation has induced greater amount of change in the body sway and SVV deviation. This may be due to the more effective stimulation of the otoliths than semicircular canals.

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Frequency-phase analysis of postural sway induced by visual motion and galvanic vestibular stimulation

Journal of Vision ◽

10.1167/8.6.1046 ◽

2010 ◽

Vol 8 (6) ◽

pp. 1046-1046 ◽

Cited By ~ 1

Author(s):

M. Kitazaki ◽

T. Kimura

Keyword(s):

Phase Analysis ◽

Visual Motion ◽

Postural Sway ◽

Vestibular Stimulation ◽

Galvanic Vestibular Stimulation ◽

Frequency Phase

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Effects of Long-Term Adaptation to Sway-Yoked Visual Motion and Galvanic Vestibular Stimulation on Visual and Vestibular Control of Posture

Presence Teleoperators & Virtual Environments ◽

10.1162/pres_a_00017 ◽

2010 ◽

Vol 19 (6) ◽

pp. 544-556 ◽

Cited By ~ 4

Author(s):

Michiteru Kitazaki ◽

Takuya Kimura

Keyword(s):

Virtual Reality ◽

Postural Control ◽

Visual Motion ◽

Postural Sway ◽

Body Movement ◽

Vestibular Stimulation ◽

Galvanic Vestibular Stimulation ◽

Motion Platform ◽

The Individual

Human postural control is a multimodal process involving visual and vestibular information. The aim of the present study was to measure individual differences in the contributions of vision and vestibular senses to postural control, and to investigate if the individual weights could be modulated by long-term adaptation to visual motion or galvanic vestibular stimulation (GVS). Since GVS is a less expensive technique than a motion platform and can be wearable, it is a promising virtual reality (VR) technology. We measured the postural sway of observers induced by a visual motion or GVS before and after a 7-day adaptation task. We divided participants into four groups. In visual adaptation groups, visual motions were presented to either enhance voluntary body movement (enhancing vision group) or inhibit voluntary body movement (inhibiting vision group). In GVS adaptation groups, GVS was applied to enhance voluntary body movement (enhancing GVS group) or inhibit voluntary body movement (inhibiting GVS group). The adaptation to enhancing body-movement-yoked visual motion decreased the GVS-induced postural sway at a low motion frequency. The adaptation to the enhancing GVS slightly increased the GVS-induced postural sway and decreased the visually-induced sway at a low motion frequency. The adaptation to the inhibiting GVS increased the GVS-induced postural sway and decreased the visually-induced sway at a high motion frequency. These data suggest that long-term adaptation can modify weights of vision and vestibular senses to control posture. These findings can be applied to training or rehabilitation systems of postural control and also to adaptive virtual-reality systems.

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Effects of galvanic vestibular stimulation on subjective visual vertical and static eye deviation

Electroencephalography and Clinical Neurophysiology ◽

10.1016/s0013-4694(97)88208-2 ◽

1997 ◽

Vol 103 (1) ◽

pp. 67

Author(s):

R Zink

Keyword(s):

Vestibular Stimulation ◽

Galvanic Vestibular Stimulation ◽

Subjective Visual Vertical ◽

Visual Vertical

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Effect of noisy galvanic vestibular stimulation on dynamic posture sway under visual deprivation in patients with bilateral vestibular hypofunction

Scientific Reports ◽

10.1038/s41598-021-83206-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Po-Yin Chen ◽

Ying-Chun Jheng ◽

Chien-Chih Wang ◽

Shih-En Huang ◽

Ting-Hua Yang ◽

...

Keyword(s):

Clinical Trial ◽

Light Exposure ◽

Light Condition ◽

Vestibular Stimulation ◽

Galvanic Vestibular Stimulation ◽

Lateral Deviation ◽

Clinical Trial Registration ◽

Vestibular Hypofunction ◽

Dark Conditions ◽

Bilateral Vestibular Hypofunction

AbstractA single-blind study to investigate the effects of noisy galvanic vestibular stimulation (nGVS) in straight walking and 2 Hz head yaw walking for healthy and bilateral vestibular hypofunction (BVH) participants in light and dark conditions. The optimal stimulation intensity for each participant was determined by calculating standing stability on a force plate while randomly applying six graded nGVS intensities (0–1000 µA). The chest–pelvic (C/P) ratio and lateral deviation of the center of mass (COM) were measured by motion capture during straight and 2 Hz head yaw walking in light and dark conditions. Participants were blinded to nGVS served randomly and imperceivably. Ten BVH patients and 16 healthy participants completed all trials. In the light condition, the COM lateral deviation significantly decreased only in straight walking (p = 0.037) with nGVS for the BVH. In the dark condition, both healthy (p = 0.026) and BVH (p = 0.017) exhibited decreased lateral deviation during nGVS. The C/P ratio decreased significantly in BVH for 2 Hz head yaw walking with nGVS (p = 0.005) in light conditions. This study demonstrated that nGVS effectively reduced walking deviations, especially in visual deprived condition for the BVH. Applying nGVS with different head rotation frequencies and light exposure levels may accelerate the rehabilitation process for patients with BVH.Clinical Trial Registration This clinical trial was prospectively registered at www.clinicaltrials.gov with the Unique identifier: NCT03554941. Date of registration: (13/06/2018).

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