Comparison of Human Ocular Torsion Patterns During Natural and Galvanic Vestibular Stimulation

2002 ◽  
Vol 87 (4) ◽  
pp. 2064-2073 ◽  
Author(s):  
Erich Schneider ◽  
Stefan Glasauer ◽  
Marianne Dieterich
Keyword(s):  
Eye Movements ◽  
Healthy Subjects ◽  
Vestibular Stimulation ◽  
Stimulus Onset ◽  
Galvanic Vestibular Stimulation ◽  
Ocular Torsion ◽  
Tonic Component ◽  
Axis Parallel ◽  
Head Rotations ◽  
Torsional Nystagmus

Galvanic vestibular stimulation (GVS) is reported to induce interindividually variable tonic ocular torsion (OT) and superimposed torsional nystagmus. It has been proposed that the tonic component results from the activation of otolith afferents. We tested our hypothesis that both the tonic and the phasic OT are mainly due to semicircular canal (SCC) stimulation by examining whether the OT patterns elicited by GVS can be reproduced by pure SCC stimulations. Using videooculography we measured the OT of six healthy subjects while two different stimuli with a duration of 20 s were applied: 1) transmastoidal GVS steps of 2 mA with the head in a pitched nose-down position and 2) angular head rotations around a combined roll-yaw axis parallel to the gravity vector with the head in the same position. The stimulation profile was individually scaled to match the nystagmus properties from GVS and consisted of a sustained velocity step of 4–12°/s on which a velocity ramp of 0.67–2°/s2 was superimposed. Since blinks were reported to induce transient torsional eye movements, the subjects were also asked to blink once 10 s after stimulus onset. Analysis of torsional eye movements under both conditions revealed no significant differences. Thus we conclude that both the tonic and the phasic OT responses to GVS can be reproduced by pure rotational stimulations and that the OT-related effects of GVS on SCC afferents are similar to natural stimulations at small amplitudes.

scholarly journals Effect of Eye-Object Distance on Body Sway during Galvanic Vestibular Stimulation

2018 ◽  
Vol 8 (11) ◽  
pp. 191 ◽  
Author(s):  
Osamu Aoki ◽  
Yoshitaka Otani ◽  
Shinichiro Morishita
Keyword(s):  
Healthy Subjects ◽  
Center Of Pressure ◽  
Force Plate ◽  
Distance Effect ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Body Sway ◽  
Mean Square ◽  
Visual Condition ◽  
Object Distance

Gazing at objects at a near distance (small eye-object distance) can reduce body sway. However, whether body sway is regulated by movement in the mediolateral or anteroposterior direction remains unclear. Galvanic vestibular stimulation (GVS) can induce body tilting in the mediolateral or anteroposterior direction. This study examined the directionality of the eye-object distance effect, using body-tilting GVS manipulations. Ten healthy subjects (aged 21.1 ± 0.3 years) stood on a force plate covered with a piece of foamed rubber and either closed their eyes or gazed at a marker located 0.5 m, 1.0 m, or 1.5 m in front of them. The GVS polarities were set to evoke rightward, forward, and backward body tilts. To compare the effects of eye-object distance in the mediolateral and anteroposterior directions, the root mean square (RMS) of the center of pressure (COP) without GVS was subtracted from the COP RMS during GVS. For swaying in the mediolateral direction, significant visual condition-related differences were found during rightward and forward GVS (p < 0.05). Thus, reductions in mediolateral body sway are more evident for smaller eye-object distances during rightward GVS. It would be appropriate to use body-tilting GVS to detect the directionality of the eye-object distance effect.

Central processing of human ocular torsion analyzed by galvanic vestibular stimulation

Neuroreport ◽  
2000 ◽  
Vol 11 (7) ◽  
pp. 1559-1563 ◽  
Author(s):  
Erich Schneider ◽  
Stefan Glasauer ◽  
Marianne Dieterich
Keyword(s):  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Ocular Torsion ◽  
Central Processing

P33. Noisy galvanic vestibular stimulation improves dynamic walking stability in healthy subjects

2015 ◽  
Vol 126 (8) ◽  
pp. e113
Author(s):  
M. Wuehr ◽  
E. Nusser ◽  
S. Krafczyk ◽  
T. Brandt ◽  
K. Jahn ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Dynamic Walking

scholarly journals Galvanic vestibular stimulation with low intensity improves dynamic balance

2021 ◽  
Vol 12 (1) ◽  
pp. 512-521
Author(s):  
Hongmei Chen ◽  
Zhen Hu ◽  
Yujuan Chai ◽  
Enxiang Tao ◽  
Kai Chen ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Center Of Pressure ◽  
Balance Control ◽  
Dynamic Balance ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Balance Performance ◽  
Improvement Rate ◽  
Average Speed ◽  
Low Intensity

Abstract Background Dynamic balance is associated with fall risk. The aim of this study is to explore the effects of galvanic vestibular stimulation with very low intensity direct current (dcGVS) on dynamic balance. Methodology We used a rocker force platform for assessing the dynamic balance performance. Center-of-pressure (COP) coordinates were acquired and decomposed to rambling (RA) and trembling (TR). We measured sway parameters, including length, average speed, and average range, affected by dcGVS at 0.01 mA with eyes open (EO) and eyes closed (EC). Results We assessed 33 young healthy subjects and found that all sway parameters were shorter in the EO condition, indicating a better dynamic balance performance. dcGVS significantly improved the dynamic balance performance both in EO and EC conditions. All the sway parameters in COP in EO were significantly shorter than those in EC, indicating a better dynamic balance performance in EO. In EO, RA had greater improvement rates than TR. In EC, only average speed had a greater improvement rate in RA, whereas length and average range had greater improvement rates in TR. These results indicate a different modulation model between EO and EC. Conclusion These findings indicate that very low intensity dcGVS improved the sway parameters of dynamic balance in young healthy subjects. Moreover, our results suggest different dynamic balance control models between having EO and EC. The mechanisms of these phenomena caused by very low intensity dcGVS require further investigation.

Galvanic Vestibular Stimulation Modifies Vection Paths in Healthy Subjects

2006 ◽  
Vol 95 (5) ◽  
pp. 3199-3207 ◽  
Author(s):  
Jean-Claude Lepecq ◽  
Catherine De Waele ◽  
Sophie Mertz-Josse ◽  
Claudine Teyssèdre ◽  
Patrice Tran Ba Huy ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Cathode Side ◽  
Motion Path ◽  
Optokinetic Stimulation ◽  
Vestibular Information ◽  
Linear Vection ◽  
Self Motion ◽  
First Time

The present study aimed at determining whether vestibular inputs contribute to the perception of the direction of self-motion. This question was approached by investigating the effects of binaural bipolar galvanic vestibular stimulation (GVS) on visually induced self-motion (i.e., vection) in healthy subjects. Stationary seated subjects were submitted to optokinetic stimulation inducing either forward or upward linear vection. While perceiving vection, they were administered trapezoidal GVS of different intensities and ramp durations. Subjects indicated the shape and direction of their perceived self-motion path throughout the experiment by a joystick, and after each trial by the manipulation of a 3D mannequin. Results show that: 1) GVS induced alterations of the path of vection; 2) these alterations occurred more often after GVS onset than after GVS offset; 3) the occurrence of vection path alterations after GVS onset depended on the intensity of GVS but not on the steepness of the GVS variation; 4) the vection path deviated laterally according to either an oblique or a curved path; and 5) the vection path deviated toward the cathode side after GVS onset. It is the first time that vestibular information, already known to contribute to the induction of vection, is shown to modify self-motion perception during the course of vection.

scholarly journals Galvanic vestibular stimulation: from basic concepts to clinical applications

2019 ◽  
Vol 121 (6) ◽  
pp. 2237-2255 ◽  
Author(s):  
Julia Dlugaiczyk ◽  
Kathrin D. Gensberger ◽  
Hans Straka
Keyword(s):  
Signal Processing ◽  
Eye Movements ◽  
Semicircular Canal ◽  
Fiber Type ◽  
Vestibular Stimulation ◽  
Nerve Fibers ◽  
Galvanic Vestibular Stimulation ◽  
Body Motion ◽  
Patient Treatment ◽  
Response Dynamics

Galvanic vestibular stimulation (GVS) plays an important role in the quest to understand sensory signal processing in the vestibular system under normal and pathological conditions. It has become a highly relevant tool to probe neuronal computations and to assist in the differentiation and treatment of vestibular syndromes. Following its accidental discovery, GVS became a diagnostic tool that generates eye movements in the absence of head/body motion. With the possibility to record extracellular and intracellular spikes, GVS became an indispensable method to activate or block the discharge in vestibular nerve fibers by cathodal and anodal currents, respectively. Bernie Cohen, in his attempt to decipher vestibular signal processing, has used this method in a number of hallmark studies that have added to our present knowledge, such as the link between selective electrical stimulation of semicircular canal nerves and the generation of directionally corresponding eye movements. His achievements paved the way for other major milestones including the differential recruitment order of vestibular fibers for cathodal and anodal currents, pronounced discharge adaptation of irregularly firing afferents, potential activation of hair cells, and fiber type-specific activation of central circuits. Previous disputes about the structural substrate for GVS are resolved by integrating knowledge of ion channel-related response dynamics of afferents, fiber type-specific innervation patterns, and central convergence and integration of semicircular canal and otolith signals. On the basis of solid knowledge of the methodology, specific waveforms of GVS are currently used in clinical diagnosis and patient treatment, such as vestibular implants and noisy galvanic stimulation.

scholarly journals Noisy Galvanic Vestibular Stimulation (Stochastic Resonance) Changes Electroencephalography Activities and Postural Control in Patients with Bilateral Vestibular Hypofunction

2020 ◽  
Vol 10 (10) ◽  
pp. 740
Author(s):  
Li-Wei Ko ◽  
Rupesh Kumar Chikara ◽  
Po-Yin Chen ◽  
Ying-Chun Jheng ◽  
Chien-Chih Wang ◽  
...  
Keyword(s):  
Postural Control ◽  
Healthy Subjects ◽  
Parietal Lobe ◽  
Center Of Pressure ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Precentral Gyrus ◽  
Neural Activities ◽  
Vestibular Hypofunction ◽  
Bilateral Vestibular Hypofunction

Patients with bilateral vestibular hypofunction (BVH) often suffer from imbalance, gait problems, and oscillopsia. Noisy galvanic vestibular stimulation (GVS), a technique that non-invasively stimulates the vestibular afferents, has been shown to enhance postural and walking stability. However, no study has investigated how it affects stability and neural activities while standing and walking with a 2 Hz head yaw turning. Herein, we investigated this issue by comparing differences in neural activities during standing and walking with a 2 Hz head turning, before and after noisy GVS. We applied zero-mean gaussian white noise signal stimulations in the mastoid processes of 10 healthy individuals and seven patients with BVH, and simultaneously recorded electroencephalography (EEG) signals with 32 channels. We analyzed the root mean square (RMS) of the center of pressure (COP) sway during 30 s of standing, utilizing AMTI force plates (Advanced Mechanical Technology Inc., Watertown, MA, USA). Head rotation quality when walking with a 2 Hz head yaw, with and without GVS, was analyzed using a VICON system (Vicon Motion Systems Ltd., Oxford, UK) to evaluate GVS effects on static and dynamic postural control. The RMS of COP sway was significantly reduced during GVS while standing, for both patients and healthy subjects. During walking, 2 Hz head yaw movements was significantly improved by noisy GVS in both groups. Accordingly, the EEG power of theta, alpha, beta, and gamma bands significantly increased in the left parietal lobe after noisy GVS during walking and standing in both groups. GVS post-stimulation effect changed EEG activities in the left and right precentral gyrus, and the right parietal lobe. After stimulation, EEG activity changes were greater in healthy subjects than in patients. Our findings reveal noisy GVS as a non-invasive therapeutic alternative to improve postural stability in patients with BVH. This novel approach provides insight to clinicians and researchers on brain activities during noisy GVS in standing and walking conditions in both healthy and BVH patients.

Effects of Galvanic Vestibular Stimulation on Perception of Subjective Vertical in Standing Humans

1998 ◽  
Vol 86 (3_suppl) ◽  
pp. 1155-1161 ◽  
Author(s):  
Marie-Françoise Tardy-Gervet ◽  
Alexandra Séverac-Cauquil
Keyword(s):  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Cathode Side ◽  
Anode Side ◽  
Ocular Torsion ◽  
Apparent Displacement ◽  
Experimental Conditions ◽  
Subjective Vertical ◽  
Central Representation ◽  
Standing Humans

The present work reinvestigated the influence of bimastoidal galvanic vestibular stimulation (0.4 mA during 10 sec.) on subjective vertical. We tested the hypothesis that deviations are directed towards the anode side, like postural tilt evoked by galvanic vestibular stimulation. 15 subjects were instructed to orient vertically in darkness a light-rod during 3 experimental conditions of control, anode right, and anode left. The statistical analysis showed that the perception of the vertical was modified according to the experimental conditions and the subjects. Angular deviations occurred towards the anode side. The results are interpreted as a consequence of a modification of the central representation of the vertical or of ocular torsion directed towards the anode side and likely to induce an apparent displacement of the rod towards the cathode side.

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