Assessing head acceleration to identify a motor threshold to galvanic vestibular stimulation

2021 ◽  
Author(s):  
Youstina Mikhail ◽  
Jonathan Charron ◽  
Jean-Marc Mac Thiong ◽  
Dorothy Barthélemy
Keyword(s):  
Center Of Pressure ◽  
Vestibular Function ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Head Acceleration ◽  
Motor Threshold ◽  
Recruitment Curve ◽  
Eyes Closed ◽  
Postural Responses ◽  
Significant Difference

Galvanic vestibular stimulation (GVS) is used to assess vestibular function, but vestibular responses can exhibit variability depending on protocols or intensities used. We measured head acceleration in healthy subjects to identify an objective motor threshold on which to base GVS intensity when assessing postural responses. Thirteen healthy right-handed subjects stood on a force platform, eyes closed, head facing forward. An accelerometer was placed on the vertex to detect head acceleration, and electromyography activity of the right soleus was recorded. GVS (200 ms; current steps 0.5;1-4mA) was applied in a binaural and bipolar configuration. 1) GVS induced a biphasic accelerometer response at a latency of 15 ms. Based on response amplitude, we constructed a recruitment curve for all participants and determined the motor threshold. In parallel, the method of limits was used to devise a more rapid approach to determine motor threshold. 2) We observed significant differences between motor threshold based on therecruitment curve and perceptual thresholds (sensation/perception of movement). No significant difference was observed between the motor threshold based on the method of limits and perceptual thresholds . 3) Using orthogonal polynomial contrasts, we observed a linear progression between multiples of the objective motor threshold (0.5, 0.75, 1, 1.5x motor threshold) and the 95% confidence ellipse area, the first peak of center of pressure velocity, and the short and medium latency responses in the soleus. Hence, an objective motor threshold and a recruitment curve for GVS were determined based on head acceleration, which could increase understanding of the vestibular system.

scholarly journals Postural responses of galvanic vestibular stimulation: comparison between groups of older adults and young people

2019 ◽  
Vol 22 (5) ◽  
Author(s):  
Regiane Luz Carvalho ◽  
Matheus Machado Gomes ◽  
Laura Ferreira de Rezende Franco ◽  
Daniela Cristina Carvalho de Abreu
Keyword(s):  
Older Adults ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Center Of Pressure ◽  
Sensory Information ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Intensity Level ◽  
Motor Strategy ◽  
Postural Responses

Abstract Objective: To evaluate the effect of vestibular manipulation on the postural sway and muscle activation of younger and older adults. Methods: The study analyzed the effects of three intensity levels of galvanic vestibular stimulation (GVS) (0.3; 0.6 and 1m) on the pattern of muscle activity and center of pressure (CP) displacements of 12 older adults (EG) and 12 young adults (CG) while maintaining their balance on a stable surface, with no vision. Results: The EG showed a positive correlation between CP displacement and muscle activity and GVS intensity. On the other hand, the magnitude of postural response in the EG was not modulated in accordance with GVS intensities. Additionally, during the highest GVS intensity level (1 mA) greater muscle activity was used to increase stiffness, decrease the amplitude of oscillation and ensure stability. This unusual response characterizes a pattern of co-activation and is perhaps a safety mechanism to ensure stability. Conclusion: The EG individuals were not able to select the appropriate motor strategy to efficiently compensate the effects of GVS. This unusual strategy reflects deficits in the vestibular system of older adults, a fact which negatively interferes with their ability to reevaluate sensory information.

scholarly journals Comparison of Postural Responses to Galvanic Vestibular Stimulation between Pilots and the General Populace

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Yang Yang ◽  
Fang Pu ◽  
Xiaoning Lv ◽  
Shuyu Li ◽  
Jing Li ◽  
...  
Keyword(s):  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Constant Current ◽  
Body Sway ◽  
Current Profile ◽  
Lateral Direction ◽  
Peak Displacement ◽  
Postural Responses ◽  
Significant Difference ◽  
Measured Position

Galvanic vestibular stimulation (GVS) can be used to study the body’s response to vestibular stimuli. This study aimed to investigate whether postural responses to GVS were different between pilots and the general populace. Bilateral bipolar GVS was applied with a constant-current profile to 12 pilots and 12 control subjects via two electrodes placed over the mastoid processes. Both GVS threshold and the center of pressure’s trajectory (COP’s trajectory) were measured. Position variability of COP during spontaneous body sway and peak displacement of COP during GVS-induced body sway were calculated in the medial-lateral direction. Spontaneous body sway was slight for all subjects, and there was no significant difference in the value of COP position variability between the pilots and controls. Both the GVS threshold and magnitude of GVS-induced body deviation were similar for different GVS polarities. GVS thresholds were similar between the two groups, but the magnitude of GVS-induced body deviation in the controls was significantly larger than that in the pilots. The pilots showed less GVS-induced body deviation, meaning that pilots may have a stronger ability to suppress vestibular illusions.

The effects of stochastic monopolar galvanic vestibular stimulation on human postural sway

2003 ◽  
Vol 12 (2-3) ◽  
pp. 77-85
Author(s):  
Anthony P. Scinicariello ◽  
J. Timothy Inglis ◽  
J.J. Collins
Keyword(s):  
Vestibular System ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Lower Sensitivity ◽  
Input Stimulus ◽  
Vestibular Perception ◽  
Afferent Nerve Endings ◽  
Young Subjects

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.

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.

Noisy galvanic vestibular stimulation effect on center of pressure sway during one-legged standing

2020 ◽  
Vol 82 ◽  
pp. 173-178
Author(s):  
Yasuto Inukai ◽  
Shota Miyaguchi ◽  
Natsuki Kobayashi ◽  
Naofumi Otsuru ◽  
Hideaki Onishi
Keyword(s):  
Center Of Pressure ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation

Cortical Projection of Peripheral Vestibular Signaling

2003 ◽  
Vol 89 (5) ◽  
pp. 2639-2646 ◽  
Author(s):  
Miklós Emri ◽  
Mihály Kisely ◽  
Zsolt Lengyel ◽  
László Balkay ◽  
Teréz Márián ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Vestibular Function ◽  
Vestibular Stimulation ◽  
Induced Response ◽  
Cortical Region ◽  
Cortical Projection ◽  
Vestibular Cortex ◽  
Caloric Vestibular Stimulation ◽  
Significant Difference ◽  
Two Populations

The cerebral projection of vestibular signaling was studied by using PET with a special differential experimental protocol. Caloric vestibular stimulation (CVS)-induced regional cerebral blood flow (rCBF) changes were investigated in two populations. Butanol perfusion scans were carried out on six healthy volunteers and on six patients following the removal of tumors from the right cerebello pontine angle. The complete loss of the vestibular function postoperatively allowed a comparison of the rCBF changes in the populations with or without this input and offered a promising functional approach whereby to delineate the cortical region most responsive to pure vestibular input. The activations by left-sided and right-sided CVS were determined for both the healthy volunteers and the patient population. Statistical analysis of the data obtained following left-sided CVS did not reveal any cerebral region for which there was a significant difference in CVS-induced response by these two populations. In the case of right-sided CVS, however, the statistical comparison of the CVS-related responses demonstrated a single contralateral area characterized by a significantly different degree of response. This cortical area corresponds to part of the cortical region described recently which can be activated by both CVS and neck vibration. It appears to be anatomically identical to the aggregate of the somatosensory area SII and the retroinsular cortex described in primates, a region identified by other investigators as an analog of the parietoinsular vestibular cortex.

scholarly journals Static Balance in Patients with Vestibular Impairments: A Preliminary Study

Scientifica ◽  
2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Hossein Talebi ◽  
Mohammad Taghi Karimi ◽  
Seyed Hamid Reza Abtahi ◽  
Niloofar Fereshtenejad
Keyword(s):  
Path Length ◽  
Center Of Pressure ◽  
Balance Control ◽  
Force Plate ◽  
Static Balance ◽  
Eyes Closed ◽  
Significant Difference ◽  
Eyes Open ◽  
Age Limits ◽  
The Difference

Aims. Vestibular system is indicated as one of the most important sensors responsible for static and dynamic postural control. In this study, we evaluated static balance in patients with unilateral vestibular impairments.Materials and Methods. We compared static balance control using Kistler force plate platform between 10 patients with unilateral vestibular impairments and 20 normal counterparts in the same sex ratio and age limits (50±7). We evaluated excursion and velocity of center of pressure (COP) and path length in anteroposterior (AP) and mediolateral (ML) planes with eyes open and with eyes closed.Results. There was no significant difference between COP excursions in ML and AP planes between both groups with eyes open and eyes closed (pvalue > 0.05). In contrast, the difference between velocity and path length of COP in the mentioned planes was significant between both groups with eyes open and eyes closed (pvalue < 0.05).Conclusions. The present study showed the static instability and balance of patients with vestibular impairments indicated by the abnormal characteristics of body balance.

scholarly journals The influence of scopolamine on motor control and attentional processes

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2008 ◽  
Author(s):  
Emma Bestaven ◽  
Charline Kambrun ◽  
Dominique Guehl ◽  
Jean-René Cazalets ◽  
Etienne Guillaud
Keyword(s):  
Motor Control ◽  
Motion Sickness ◽  
Center Of Pressure ◽  
Vestibular Nucleus ◽  
Parabolic Flight ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Balance Test ◽  
Attentional Processes ◽  
Perception Of Verticality

Background:Motion sickness may be caused by a sensory conflict between the visual and the vestibular systems. Scopolamine, known to be the most effective therapy to control the vegetative symptoms of motion sickness, acts on the vestibular nucleus and potentially the vestibulospinal pathway, which may affect balance and motor tasks requiring both attentional process and motor balance. The aim of this study was to explore the effect of scopolamine on motor control and attentional processes.Methods:Seven subjects were evaluated on four different tasks before and after a subcutaneous injection of scopolamine (0.2 mg): a one-minute balance test, a subjective visual vertical test, a pointing task and a galvanic vestibular stimulation with EMG recordings.Results:The results showed that the reaction time and the movement duration were not modified after the injection of scopolamine. However, there was an increase in the center of pressure displacement during the balance test, a decrease in EMG muscle response after galvanic vestibular stimulation and an alteration in the perception of verticality.Discussion:These results confirm that low doses of scopolamine such as those prescribed to avoid motion sickness have no effect on attentional processes, but that it is essential to consider the responsiveness of each subject. However, scopolamine did affect postural control and the perception of verticality. In conclusion, the use of scopolamine to prevent motion sickness must be considered carefully because it could increase imbalances in situations when individuals are already at risk of falling (e.g., sailing, parabolic flight).

scholarly journals The Effects of Stochastic Galvanic Vestibular Stimulation on Body Sway and Muscle Activity

2020 ◽  
Vol 14 ◽  
Author(s):  
Akiyoshi Matsugi ◽  
Kosuke Oku ◽  
Nobuhiko Mori
Keyword(s):  
Soleus Muscle ◽  
Muscle Activity ◽  
Center Of Pressure ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
The Body ◽  
Lower Limbs ◽  
Body Sway ◽  
Eyes Open ◽  
Significant Increment

Objective: This study aimed to investigate whether galvanic vestibular stimulation with stochastic noise (nGVS) modulates the body sway and muscle activity of the lower limbs, depending on visual and somatosensory information from the foot using rubber-foam.Methods: Seventeen healthy young adults participated in the study. Each subject maintained an upright standing position on a force plate with/without rubber-foam, with their eyes open/closed, to measure the position of their foot center of pressure. Thirty minutes after baseline measurements under four possible conditions (eyes open/closed with/without rubber-foam) performed without nGVS (intensity: 1 mA, duration: 40 s), the stimulation trials (sham-nGVS/real-nGVS) were conducted under the same conditions in random order, which were then repeated a week or more later. The total center of pressure (COP) path length movement (COP-TL) and COP movement velocity in the mediolateral (Vel-ML) and anteroposterior (Vel-AP) directions were recorded for 30 s during nGVS. Furthermore, electromyography activity of the right tibial anterior muscle and soleus muscle was recorded for the same time and analyzed.Results: Three-way analysis of variance and post-hoc multiple comparison revealed a significant increment in COP-related parameters by nGVS, and a significant increment in soleus muscle activity on rubber. There was no significant effect of eye condition on any parameter.Conclusions: During nGVS (1 mA), body sway and muscle activity in the lower limb may be increased depending not on the visual condition, but on the foot somatosensory condition.

scholarly journals Greater exposure to repetitive subconcussive head impacts is associated with vestibular dysfunction and balance impairments during walking

Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S27.2-S27
Author(s):  
Fernando Santos ◽  
Jaclyn B Caccese ◽  
Mariana Gongora ◽  
Ian Sotnek ◽  
Elizabeth Kaye ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Balance Control ◽  
Center Of Mass ◽  
Vestibular Stimulation ◽  
Vestibular Dysfunction ◽  
Foot Placement ◽  
Head Impacts ◽  
Eyes Closed ◽  
Balance Deficits ◽  
Soccer Heading

Exposure to repetitive subconcussive head impacts (RSHI), specifically soccer heading, is associated with white matter microstructural changes and cognitive performance impairments. However, the effect of soccer heading exposure on vestibular processing and balance control during walking has not been studied. Galvanic vestibular stimulation (GVS) is a tool that can be used to probe the vestibular system during standing and walking. The purpose of this study was to investigate the association of soccer heading with subclinical balance deficits during walking. Twenty adult amateur soccer players (10 males and 10 females, 22.3 ± 4.5 years, 170.5 ± 9.8 cm, 70.0 ± 10.5 kg) walked along a foam walkway with the eyes closed under 2 conditions: with GVS (∼40 trials) and without GVS (∼40 trials). Outcome measures included mediolateral center-of-mass (COM), center-of-pressure (COP) separation, foot placement, mediolateral ankle modulation, hip adduction, and ankle push off. For each balance mechanism, a GVS response was calculated (GVS, mean [without GVS]). In addition, participants completed a questionnaire, reporting soccer heading exposure over the past year. A linear regression model was used to determine if vestibular processing and balance during walking were related to RSHI exposure. Both foot placement (R2 = 0.324, p = 0.009) and hip adduction (R2 = 0.183, p = 0.50) were predicted by RSHI; whereby, greater exposure to RSHI was associated with greater foot placement and hip adduction responses. However, COM-COP separation (R2 < 0.001, p = 0.927), ankle modulation (R2 = 0.037, p = 0.417), and push off (R2 < 0.001, p = 0.968) were not related to RSHI exposure. Individuals who were exposed to greater RSHI were more perturbed by vestibular stimulation during walking, suggesting that there may be vestibular dysfunction and balance impairments with frequent heading; specifically, individuals with greater exposure to RSHI responded with larger foot placement and hip adduction responses to GVS.

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