scholarly journals Reduction of cybersickness during and immediately following noisy galvanic vestibular stimulation

2019 ◽  
Author(s):  
Séamas Weech ◽  
Travis Wall ◽  
Michael Barnett-Cowan

AbstractThe mechanism underlying cybersickness during virtual reality (VR) exposure is still poorly understood, although research has highlighted a causal role for visual-vestibular sensory conflict. Recently established methods for reducing cybersickness include galvanic vestibular stimulation (GVS) to mimic absent vestibular cues in VR, or vibration of the vestibular organs to add noise to the sensory modality. Here, we examined if applying noise to the vestibular system using noisy-current GVS also affects sickness severity in VR. Participants were exposed to one of two VR games that were classified as either moderate or intense with respect to their nauseogenic effects. The VR content lasted for 50 minutes and was broken down into 3 blocks: 30 minutes of gameplay during exposure to either noisy GVS (±1750 μA) or sham stimulation (0 μA), and 10 minutes of gameplay before and after this block. We characterized the effects of noisy GVS in terms of post-minus-pre-exposure cybersickness scores. For the intense VR content, we found a main effect of noisy vestibular stimulation. Participants reported lower cybersickness scores during and directly after exposure to GVS. However, this difference was quickly extinguished (∼3-6 min) after further exposure to VR, indicating that sensory adaptation did not persist after stimulation was terminated. In contrast, there were no differences between the sham and GVS group for the moderate VR content. The results show the potential for reducing cybersickness with simple non-invasive sensory stimulation. We discuss the prospect that noise-induced sensory re-weighting is responsible for the observed effects, and address other possible mechanisms.

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Gyutae Kim ◽  
Sangmin Lee ◽  
Kyu-Sung Kim

Vestibular nucleus (VN) and cerebellar flocculus are known as the core candidates for the neuroplasticity of vestibular system. However, it has been still elusive how to induce the artificial neuroplasticity, especially caused by an electrical stimulation, and assess the neuronal information related with the plasticity. To understand the electrically induced neuroplasticity, the neuronal potentials in VN responding to the repeated electrical stimuli were examined. Galvanic vestibular stimulation (GVS) was applied to excite the neurons in VN, and their activities were measured by an extracellular neural recording technique. Thirty-eight neuronal responses (17 for the regular and 21 for irregular neurons) were recorded and examined the potentials before and after stimulation. Two-third of the population (63.2%, 24/38) modified the potentials under the GVS repetition before stimulation (p=0.037), and more than half of the population (21/38, 55.3%) changed the potentials after stimulation (p=0.209). On the other hand, the plasticity-related neuronal modulation was hardly observed in the temporal responses of the neurons. The modification of the active glutamate receptors was also investigated to see if the repeated stimulation changed the number of both types of glutamate receptors, and the results showed that AMPA and NMDA receptors decreased after the repeated stimuli by 28.32 and 16.09%, respectively, implying the modification in the neuronal amplitudes.


2018 ◽  
Vol 72 (6) ◽  
pp. 1550-1560 ◽  
Author(s):  
Tanya Karn ◽  
Michael E Cinelli

The purpose of this study was to determine the effects of galvanic vestibular stimulation (GVS) on path trajectory and body rotation during a triangle completion task. Participants ( N = 17, female, 18-30 years) completed the triangle completion task in virtual reality using two different size triangles. GVS was delivered at three times each participant’s threshold in either the left or right direction prior to the final leg of the triangle and continued until the participant reached their final position. Whole body kinematics were collected using an NDI Optotrak motion tracking system. Results revealed a significant main effect of GVS on arrival error such that no GVS (NGVS) had significantly smaller arrival errors than when GVS was administered. There was also a significant main effect of GVS on angular error such that NGVS had significantly smaller error than GVSaway and GVStowards. There was no significant difference between GVS trials in path variability during the final leg on route to the final position. These results demonstrate that vestibular perturbation reduced the accuracy of the triangle completion task, affecting path trajectory and body position during a path integration task in the absence of visual cues.


2021 ◽  
Author(s):  
Andrea Pilotto ◽  
Maria Cristina Rizzetti ◽  
Alberto Lombardi ◽  
Clint Hansen ◽  
Michele Biggi ◽  
...  

AbstractThere are no effective treatments in progressive supranuclear palsy (PSP). The aim of this study was to test the efficacy of theta burst repetitive transcranial magnetic stimulation (rTMS) on postural instability in PSP. Twenty PSP patients underwent a session of sham or real cerebellar rTMS in a crossover design. Before and after stimulation, static balance was evaluated with instrumented (lower back accelerometer, Rehagait®, Hasomed, Germany) 30-s trials in semitandem and tandem positions. In tandem and semitandem tasks, active stimulation was associated with increase in time without falls (both p=0.04). In the same tasks, device-extracted parameters revealed significant improvement in area (p=0.007), velocity (p=0.005), acceleration and jerkiness of sway (p=0.008) in real versus sham stimulation. Cerebellar rTMS showed a significant effect on stability in PSP patients, when assessed with mobile digital technology, in a double-blind design. These results should motivate larger and longer trials using non-invasive brain stimulation for PSP patients.


Author(s):  
Patrick Veit-Haibach ◽  
Martin W. Huellner ◽  
Martin Banyai ◽  
Sebastian Mafeld ◽  
Johannes Heverhagen ◽  
...  

Abstract Objectives The purpose of this study was the assessment of volumetric CT perfusion (CTP) of the lower leg musculature in patients with symptomatic peripheral arterial disease (PAD) before and after interventional revascularisation. Methods Twenty-nine consecutive patients with symptomatic PAD of the lower extremities requiring interventional revascularisation were assessed prospectively. All patients underwent a CTP scan of the lower leg, and hemodynamic and angiographic assessment, before and after intervention. Ankle-brachial pressure index (ABI) was determined. CTP parameters were calculated with a perfusion software, acting on a no outflow assumption. A sequential two-compartment model was used. Differences in CTP parameters were assessed with non-parametric tests. Results The cohort consisted of 24 subjects with an occlusion, and five with a high-grade stenosis. The mean blood flow before/after (BFpre and BFpost, respectively) was 7.42 ± 2.66 and 10.95 ± 6.64 ml/100 ml*min−1. The mean blood volume before/after (BVpre and BVpost, respectively) was 0.71 ± 0.35 and 1.25 ± 1.07 ml/100 ml. BFpost and BVpost were significantly higher than BFpre and BVpre in the treated limb (p = 0.003 and 0.02, respectively), but not in the untreated limb (p = 0.641 and 0.719, respectively). Conclusions CTP seems feasible for assessing hemodynamic differences in calf muscles before and after revascularisation in patients with symptomatic PAD. We could show that CTP parameters BF and BV are significantly increased after revascularisation of the symptomatic limb. In the future, this quantitative method might serve as a non-invasive method for surveillance and therapy control of patients with peripheral arterial disease. Key Points • CTP imaging of the lower limb in patients with symptomatic PAD seems feasible for assessing hemodynamic differences before and after revascularisation in PAD patients. • This quantitative method might serve as a non-invasive method, for surveillance and therapy control of patients with PAD.


2021 ◽  
pp. 251660852098429
Author(s):  
Dorcas B. C. Gandhi ◽  
Ivy Anne Sebastian ◽  
Komal Bhanot

Sensory dysfunction is one of the common impairments that occurs post stroke. With sensory changes in all modalities, it also affects the quality of life and incites suicidal thoughts. The article attempts to review and describe the current evidence of various approaches of assessment and rehabilitation for post-stroke sensory dysfunction. After extensive electronic database search across Medline, Embase, EBSCO, and Cochrane library, it generated 2433 results. After screening according to inclusion and exclusion criteria, we included 11 studies. We categorized data based on type of sensory deficits and prevalence, role of sensory system on motor behavior, type of intervention, sensory modality targeted, and dosage of intervention and outcome measures used for rehabilitation. Results found the strong evidence of involvement of primary and secondary motor areas involved in processing and responding to somatosensation, respectively. We divided rehabilitation approaches into sensory stimulation approach and sensory retraining approach focused on using external stimuli and relearning, respectively. However, with varied aims and targeted sensory involvement, the study applicability is affected. Thus, this emerges the need of extensive research in future for evidence-based practice of assessments and rehabilitation on post-stroke sensory rehabilitation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Po-Yin Chen ◽  
Ying-Chun Jheng ◽  
Chien-Chih Wang ◽  
Shih-En Huang ◽  
Ting-Hua Yang ◽  
...  

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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