scholarly journals Noisy galvanic vestibular stimulation has a greater ameliorating effect on posture in unstable subjects: a feasibility study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chisato Fujimoto ◽  
Makoto Kinoshita ◽  
Teru Kamogashira ◽  
Naoya Egami ◽  
Takuya Kawahara ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Foam Rubber ◽  
Eyes Closed ◽  
Healthy Elderly ◽  
Eyes Open ◽  
Optimal Intensity ◽  
Effective Intensity

AbstractAmeliorating effect of noisy galvanic vestibular stimulation (nGVS) on posture varies among subjects. In this feasibility study, we investigated the association between original postural instability and the ameliorating effect of nGVS on posture. Data were collected in a previously published study. Thirty healthy elderly were recruited. Two nGVS sessions (30 min or 3 h) were performed in a randomised order. The optimal intensity of nGVS, the most effective intensity for improving posture, was determined before each session. Posture was measured for 30 s during and after nGVS in the eyes-closed/foam rubber condition. The velocity, envelopment area, and root mean square of the centre of pressure movement without nGVS were significantly larger in the group with an optimal intensity than those in the group without an optimal intensity. There was a significant positive correlation between these values and the long-term ameliorating effects. The ratio of the values in the eyes-closed/foam rubber condition to those in the eyes-open condition was significantly larger in the group with an optimal intensity, and had a significant correlation with the long-term ameliorating effects. The ameliorating effects are greater in subjects who were originally unstable and in those whose postural stability was relatively independent of vestibular input.

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 Shifts in broadband power and alpha peak frequency observed during long-term isolation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jan Weber ◽  
Timo Klein ◽  
Vera Abeln
Keyword(s):  
Sensory Deprivation ◽  
Peak Frequency ◽  
Neuronal Population ◽  
Confined Space ◽  
Eyes Closed ◽  
Eyes Open ◽  
Eeg Recordings ◽  
Induced Changes ◽  
Alpha Peak

Abstract Prolonged periods of social isolation and spatial confinement do not only represent an issue that needs to be faced by a few astronauts during space missions, but can affect all of us as recently shown during pandemic situations. The fundamental question, how the brain adapts to periods of sensory deprivation and re-adapts to normality, has only received little attention. Here, we use eyes closed and eyes open resting-state electroencephalographic (EEG) recordings to investigate how neural activity is altered during 120 days of isolation in a spatially confined, space-analogue environment. After disentangling oscillatory patterns from 1/f activity, we show that isolation leads to a reduction in broadband power and a flattening of the 1/f spectral slope. Beyond that, we observed a reduction in alpha peak frequency during isolation, but did not find strong evidence for isolation-induced changes that are of oscillatory nature. Critically, all effects reversed upon release from isolation. These findings suggest that isolation and concomitant sensory deprivation lead to an enhanced cortical deactivation which might be explained by a reduction in the mean neuronal population firing rate.

scholarly journals Effect of hearing aids on body balance function in non-reverberant condition: A posturographic study

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258590
Author(s):  
Chihiro Ninomiya ◽  
Harukazu Hiraumi ◽  
Kiyoshi Yonemoto ◽  
Hiroaki Sato
Keyword(s):  
Hearing Aids ◽  
Center Of Pressure ◽  
Hearing Aid ◽  
Normal Hearing ◽  
Balance Function ◽  
Maximum Displacement ◽  
Body Balance ◽  
Foam Rubber ◽  
Eyes Closed ◽  
Eyes Open

Objective The purpose of this study was to evaluate the effect of hearing aids on body balance function in a strictly controlled auditory environment. Methods We recorded the findings of 10 experienced hearing aid users and 10 normal-hearing participants. All the participants were assessed using posturography under eight conditions in an acoustically shielded non-reverberant room: (1) eyes open with sound stimuli, with and without foam rubber, (2) eyes closed with sound stimuli, with and without foam rubber, (3) eyes open without sound stimuli, with and without foam rubber, and (4) eyes closed without sound stimuli, with and without foam rubber. Results The auditory cue improved the total path area and sway velocity in both the hearing aid users and normal-hearing participants. The analysis of variance showed that the interaction among eye condition, sound condition, and between-group factor was significant in the maximum displacement of the center-of-pressure in the mediolateral axis (F [1, 18] = 6.19, p = 0.02). The maximum displacement of the center-of-pressure in the mediolateral axis improved with the auditory cues in the normal-hearing participants in the eyes closed condition (5.4 cm and 4.7 cm, p < 0.01). In the hearing aid users, this difference was not significant (5.9 cm and 5.7 cm, p = 0.45). The maximum displacement of the center-of-pressure in the anteroposterior axis improved in both the hearing aid users and the normal-hearing participants.

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 Influence of gender on static balance in healthy community dwelling elderly: a comparison using posturography

2020 ◽  
Vol 8 (8) ◽  
pp. 2950
Author(s):  
Atiya A. Shaikh ◽  
Rutuja D. Joshi
Keyword(s):  
Community Dwelling ◽  
P Value ◽  
Static Balance ◽  
Clinical Test ◽  
Sensory Interaction ◽  
Male And Female ◽  
Eyes Closed ◽  
Healthy Elderly ◽  
Significant Difference ◽  
Eyes Open

Background: Background and need of study- Influence of gender on balance is still controversial. Previous researchers have done studies using traditional methods. These methods may fail to detect subtle changes in balance difference. A tool like posturography which is highly specific may help to for accurate assessment and hence precise conclusion. Aim was to compare balance scores of male and female elderly using modified Clinical Test of Sensory Interaction on Balance (CTSIB).Methods: There were 56 healthy elderly ambulating without an assistive device and free from any neurological and orthopedic problems were assessed for their balance abilities using mCTSIB of balance master(standing on firm surface with eyes open, with eyes closed, standing on foam surface with eyes open and with eyes closed). Sway velocity was assessed using Unpaired t test.Results: There was a no significant difference in scores of modified CTSIB between male and female elderly ( p value>0.005).Conclusions: Gender has no effect on static balance abilities between male and female elderly while performing modified clinical test of sensory interaction on balance.

scholarly journals Galvanic Vestibular Stimulation Improves Spatial Cognition After Unilateral Labyrinthectomy in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Thanh Tin Nguyen ◽  
Gi-Sung Nam ◽  
Jin-Ju Kang ◽  
Gyu Cheol Han ◽  
Ji-Soo Kim ◽  
...  
Keyword(s):  
Spatial Memory ◽  
Spatial Cognition ◽  
Motor Coordination ◽  
Spatial Working Memory ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Control Group ◽  
Y Maze ◽  
Unilateral Labyrinthectomy

Objectives: To investigate the deficits of spatial memory and navigation from unilateral vestibular deafferentation (UVD) and to determine the efficacy of galvanic vestibular stimulation (GVS) for recovery from these deficits using a mouse model of unilateral labyrinthectomy (UL).Methods: Thirty-six male C57BL/6 mice were allocated into three groups that comprise a control group and two experimental groups, UVD with (GVS group) and without GVS intervention (non-GVS group). In the experimental groups, we assessed the locomotor and cognitive behavioral function before (baseline) and 3, 7, and 14 days after surgical UL, using the open field (OF), Y maze, and Morris water maze (MWM) tests. In the GVS group, the stimulations were applied for 30 min daily from postoperative day (POD) 0–4 via the electrodes inserted subcutaneously close to both bony labyrinths.Results: Locomotion and spatial cognition were significantly impaired in the mice with UVD non-GVS group compared to the control group. GVS significantly accelerated recovery of locomotion compared to the control and non-GVS groups on PODs 3 (p &lt; 0.001) and 7 (p &lt; 0.05, Kruskal–Wallis and Mann–Whitney U tests) in the OF and Y maze tests. The mice in the GVS group were better in spatial working memory assessed with spontaneous alternation performance and spatial reference memory assessed with place recognition during the Y maze test than those in the non-GVS group on POD 3 (p &lt; 0.001). In addition, the recovery of long-term spatial navigation deficits during the MWM, as indicated by the escape latency and the probe trial, was significantly better in the GVS group than in the non-GVS group 2 weeks after UVD (p &lt; 0.01).Conclusions: UVD impairs spatial memory, navigation, and motor coordination. GVS accelerated recoveries in short- and long-term spatial memory and navigation, as well as locomotor function in mice with UVD, and may be applied to the patients with acute unilateral vestibular failure.

scholarly journals Velocity of body lean evoked by leg muscle vibration potentiate the effects of vestibular stimulation on posture

2007 ◽  
pp. 829-832
Author(s):  
O Dzurková ◽  
F Hlavačka
Keyword(s):  
Body Movement ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
The Body ◽  
Muscle Vibration ◽  
Quiet Stance ◽  
Foot Pressure ◽  
Galvanic Stimulation ◽  
Eyes Closed ◽  
Leg Muscle

To investigate the vestibular and somatosensory interaction in human postural control, a galvanic vestibular stimulation of cosine bell shape resulting in a small forward or backward body lean was paired with three vibrations of both soleus muscles. The induced body lean was registered by the position of the center of foot pressure (CoP). During a quiet stance with eyes closed the vibration of both soleus muscles with frequency (of) 40 Hz, 60 Hz and 80 Hz resulted in the body lean backward with velocities related to the vibration frequencies. The vestibular galvanic stimulation with the head turned to the right caused forward or backward modification of CoP backward response to the soleus muscles vibration and peaked at 1.5-2 s following the onset of the vibration. The effect of the paired stimulation was larger than the summation of the vestibular stimulation during the quiet stance and a leg muscle vibration alone. The enhancement of the galvanic stimulation was related to the velocity of body lean induced by the leg muscle vibration. The galvanic vestibular stimulation during a faster body movement had larger effects than during a slow body lean or the quiet stance. The results suggest that velocity of a body postural movement or incoming proprioceptive signal from postural muscles potentiate the effects of simultaneous vestibular stimulations on posture.

scholarly journals Effects of Noisy Galvanic Vestibular Stimulation on Standing Balance – No Evidence for Stochastic Resonance in Young Healthy Adults

2021 ◽  
Author(s):  
Lorenz Assländer ◽  
Louis-Solal Giboin ◽  
Markus Gruber ◽  
Roman Schniepp ◽  
Max Wühr
Keyword(s):  
Stochastic Resonance ◽  
Goodness Of Fit ◽  
Vestibular Stimulation ◽  
Galvanic Vestibular Stimulation ◽  
Healthy Adults ◽  
Body Sway ◽  
Response Dynamics ◽  
Eyes Closed ◽  
Performance Metric ◽  
Performance Curves

Abstract Noisy galvanic vestibular stimulation (nGVS) at imperceptible levels has been shown to reduce body sway. This improvement was commonly attributed to the mechanism of stochastic resonance (SR). However, it has never been explicitly tested whether nGVS-induced effects on body sway consistently follow a SR-like bell-shaped performance curve with optimal improvements at intermediate noise intensities. To test this, body sway in 21 young healthy participants was measured during varying nGVS amplitudes while standing with eyes closed in 3 conditions (quiet stance, sway referencing, sinusoidal platform tilts). Presence of SR-compatible response dynamics in each trial was assessed (1) by a goodness-of-fit analysis using an established SR-curve model and (2) by ratings from 3 human experts. In accordance to theory, we found reductions of body sway at one nGVS amplitude in most trials (75-95%). However, only few trials exhibited SR-compatible bell-shaped performance curves with increasing noise amplitudes (10-33%). Instead, body sway measures rather fluctuated randomly across nGVS amplitudes. This implies that, at least in young healthy adults, nGVS effects on body sway are incompatible with SR. Thus, previously reported reductions of body sway at particular nGVS intensities more likely result from inherent variations of the performance metric or by other yet unknown mechanisms.

scholarly journals The effects of long-term exercise training on the neural control of walking

2021 ◽  
Author(s):  
Morteza Yaserifar ◽  
Ziya Fallah Mohammadi ◽  
Sayed Esmaiel Hosseininejad ◽  
Iman Esmaili Paeen Afrakoti ◽  
Kenneth Meijer ◽  
...  
Keyword(s):  
Neural Control ◽  
Treadmill Walking ◽  
Muscle Synergies ◽  
Muscle Coordination ◽  
Overground Walking ◽  
Eyes Closed ◽  
Gait Parameters ◽  
Eyes Open ◽  
The Right

AbstractHow does long-term training modify the neural control of walking? Here we investigate changes in kinematics and muscle synergies of the lower extremities in 10 soccer players and 10 non-athletes while they walked with eyes open or closed either overground or on a treadmill. Electromyography (EMG) was acquired from eight muscles of the right leg and foot switch data were recorded to extract temporal gait parameters. Muscle synergies were extracted using non-negative matrix factorisation for each participant and condition separately and were then grouped using k-means clustering. We found that both the cycle and stance duration were longer during treadmill walking compared to overground walking, whereas the swing phase was longer during the eyes-open compare to the eyes-closed condition. On average, more synergies were expressed in the athlete compared to the non-athlete group and during treadmill compared to overground walking. We found that synergy 2 involved in ankle plantarflexion was more often activated in athletes than in non-athletes. We did not find statistical group differences for the synergy metrics but several differences were observed between conditions: peak activation of synergy 5 (VM and VL muscles) increased during overground walking compared to treadmill walking. In addition, reduced activation of synergy 3 (TA muscle) and synergy 4 was observed during eyes-closed compared to eyes-open walking. These findings suggest that during walking long-term training results in greater flexibility of muscle coordination by recruiting additional synergies, but we found no evidence that long-term training affects the activation patterns of these synergies.

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