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Journal of Vision Dec 2023Stationarity perception refers to the ability to accurately perceive the surrounding visual environment as world-fixed during self-motion. Perception of stationarity...
Stationarity perception refers to the ability to accurately perceive the surrounding visual environment as world-fixed during self-motion. Perception of stationarity depends on mechanisms that evaluate the congruence between retinal/oculomotor signals and head movement signals. In a series of psychophysical experiments, we systematically varied the congruence between retinal/oculomotor and head movement signals to find the range of visual gains that is compatible with perception of a stationary environment. On each trial, human subjects wearing a head-mounted display execute a yaw head movement and report whether the visual gain was perceived to be too slow or fast. A psychometric fit to the data across trials reveals the visual gain most compatible with stationarity (a measure of accuracy) and the sensitivity to visual gain manipulation (a measure of precision). Across experiments, we varied 1) the spatial frequency of the visual stimulus, 2) the retinal location of the visual stimulus (central vs. peripheral), and 3) fixation behavior (scene-fixed vs. head-fixed). Stationarity perception is most precise and accurate during scene-fixed fixation. Effects of spatial frequency and retinal stimulus location become evident during head-fixed fixation, when retinal image motion is increased. Virtual Reality sickness assessed using the Simulator Sickness Questionnaire covaries with perceptual performance. Decreased accuracy is associated with an increase in the nausea subscore, while decreased precision is associated with an increase in the oculomotor and disorientation subscores.
Topics: Humans; Head Movements; Motion; Psychometrics; Virtual Reality; Perception
PubMed: 38127329
DOI: 10.1167/jov.23.14.7 -
Frontiers in Neuroscience 2023Vestibular provocation is one of the main causes of flight illusions, and its occurrence is closely related to the susceptibility of motion sickness (MS). However,...
OBJECTIVE
Vestibular provocation is one of the main causes of flight illusions, and its occurrence is closely related to the susceptibility of motion sickness (MS). However, existing training programs have limited effect in improving the resistance to motion sickness. In this study, we investigated the effects of hypoxia acclimatization training (HAT) on the resistance to motion sickness.
METHODS
Healthy military college students were identified as subjects according to the criteria. MS model was induced by a rotary chair. Experimental groups included control, HAT, 3D roller training (3DRT), and combined training.
RESULTS
The Graybiel scores were decreased in the HAT group and the 3DRT group and further decreased in the combined training group in MS induced by the rotary chair. Participants had a significant increase in blood pressure after the rotary chair test and a significant increase in the heart rate during the rotary chair test, but these changes disappeared in all three training groups. Additionally, LFn was increased, HFn was decreased, and LF/HF was increased accordingly during the rotary chair test in the control group, but the changes of these three parameters were completely opposite in the three training groups during the rotary chair test. Compared with the control group, the decreasing changes in pupillary contraction velocity (PCV) and pupillary minimum diameter (PMD) of the three training groups were smaller. In particular, the binocular PCV changes were further attenuated in the combined training group.
CONCLUSION
Our research provides a possible candidate solution for training military pilots in the resistance to motion sickness.
PubMed: 38125401
DOI: 10.3389/fnins.2023.1216998 -
Journal of Microbiology & Biology... Dec 2023The advent of virtual reality (VR) in education offers unique possibilities for facilitating cooperative learning strategies, particularly in fields demanding intricate...
The advent of virtual reality (VR) in education offers unique possibilities for facilitating cooperative learning strategies, particularly in fields demanding intricate spatial understanding, such as gross anatomy. This study investigates the impact of integrating cooperative learning strategies within a VR-based gross anatomy curriculum, focusing on enhancing students' anatomy knowledge and skills. We analyzed the performance of two cohorts of first-year nursing students across five semesters (2016-2020), where traditional learning methods were used in the first three semesters (2016-2018), and a VR-based cooperative learning approach was adopted in the last two semesters (2019-2020). Our findings suggest that the VR-based cooperative learning group achieved significantly higher scores in their gross anatomy laboratory courses compared to their counterparts learning through traditional methods. This research provides valuable insights into how the integration of VR technology and cooperative learning strategies can not only enhance learning outcomes but also improve the VR learning experience by reducing motion sickness. It accentuates the potential of VR-based cooperative learning as an impactful educational tool in anatomy education. Future research should further explore the optimal integration of VR and cooperative learning strategies in diverse course types and their potential to enhance educational outcomes and the learning experience.
PubMed: 38108010
DOI: 10.1128/jmbe.00100-23 -
Frontiers in Physiology 2023In the early 1970s, nine astronauts participated in missions to the Skylab space station. During two preflight testing sessions at the Naval Aerospace Medical Research...
In the early 1970s, nine astronauts participated in missions to the Skylab space station. During two preflight testing sessions at the Naval Aerospace Medical Research Laboratory in Pensacola, the amplitudes of their ocular counter-rolling (OCR) during body tilts were assessed to determine if their vestibular functions were within normal ranges. We recently re-evaluated this data to determine asymmetry of each astronaut's OCR response and their OCR slope from sigmoid fits during static leftward and rightward body tilts, which we then compared with their Coriolis sickness susceptibility index (CSSI) on the ground, their motion sickness symptom scores during 0 g maneuvers in parabolic flight, and the severity of the symptoms of space motion sickness (SMS) they reported during their spaceflights. We arranged the astronauts in rank order for SMS severity based on the SMS symptoms they reported during spaceflight and the amount of anti-motion sickness medication they used. As previously reported, the OCR amplitudes of these astronauts were within the normal range. We determined that the OCR amplitudes were not correlated with SMS severity ranking, CSSI, or motion sickness symptoms experienced during parabolic flight. Indices of asymmetry in the OCR reflex were generally small and poorly correlated with SMS scores; however, the only subject with a high index of asymmetry also ranked highly for SMS. Although OCR slope, CSSI, and motion sickness symptoms induced during parabolic flight were each only moderately correlated with SMS severity ranking (rho = 0.41-0.44), a combined index that included all three parameters with equal weighting was significantly correlated with SMS severity ranking (rho = 0.71, = 0.015). These results demonstrate the challenge of predicting an individual's susceptibility to SMS by measuring a single test parameter in a terrestrial environment and from a limited sample size.
PubMed: 38074314
DOI: 10.3389/fphys.2023.1303938 -
World Journal of Clinical Cases Nov 2023Postoperative nausea and vomiting (PONV) are common complications that affect the recovery and well-being of elderly patients undergoing gastrointestinal laparoscopic...
BACKGROUND
Postoperative nausea and vomiting (PONV) are common complications that affect the recovery and well-being of elderly patients undergoing gastrointestinal laparoscopic surgery.
AIM
To investigate the effect of butorphanol on PONV in this patient population.
METHODS
A total of 110 elderly patients (≥ 65 years old) who underwent gastrointestinal laparoscopic surgery were randomly assigned to receive butorphanol (40 μg/kg) or sufentanil (0.3 μg/kg) during anesthesia induction in a 1:1 ratio. The measured outcomes included the incidence of PONV at 48 h after surgery, intraoperative dose of propofol and remifentanil, Bruggrmann Comfort Scale score in the postanesthesia care unit (PACU), number of compressions for postoperative patient-controlled intravenous analgesia (PCIA), and time to first flatulence after surgery.
RESULTS
The results revealed a noteworthy reduction in the occurrence of PONV at 24 h after surgery in the butorphanol group, when compared to the sufentanil group (T1: 23.64% 5.45%, T2: 43.64% 20.00%, < 0.05). However, no significant variations were observed between the two groups, in terms of the clinical characteristics, such as the PONV or motion sickness history, intraoperative and postoperative 48-h total infusion volume and hemodynamic parameters, intraoperative dose of propofol and remifentanil, number of postoperative PCIA compressions, time until the first occurrence of postoperative flatulence, and incidence of PONV at 48 h post-surgery (all, > 0.05). Furthermore, patients in the butorphanol group were more comfortable, when compared to patients in the sufentanil group in the PACU.
CONCLUSION
The present study revealed that butorphanol can be an efficacious substitute for sufentanil during anesthesia induction to diminish PONV within 24 h following gastrointestinal laparoscopic surgery in the elderly, simultaneously improving patient comfort in the PACU.
PubMed: 38073686
DOI: 10.12998/wjcc.v11.i32.7806 -
Frontiers in Neurology 2023To counteract gravity, trunk motion, and other perturbations, the human head-neck system requires continuous muscular stabilization. In this study, we combine a...
BACKGROUND
To counteract gravity, trunk motion, and other perturbations, the human head-neck system requires continuous muscular stabilization. In this study, we combine a musculoskeletal neck model with models of sensory integration (SI) to unravel the role of vestibular, visual, and muscle sensory cues in head-neck stabilization and relate SI conflicts and postural instability to motion sickness.
METHOD
A 3D multisegment neck model with 258 Hill-type muscle elements was extended with postural stabilization using SI of vestibular (semicircular and otolith) and visual (rotation rate, verticality, and yaw) cues using the multisensory observer model (MSOM) and the subjective vertical conflict model (SVC). Dynamic head-neck stabilization was studied using empirical datasets, including 6D trunk perturbations and a 4 m/s slalom drive inducing motion sickness.
RESULTS
Recorded head translation and rotation are well matched when using all feedback loops with MSOM or SVC or assuming perfect perception. A basic version of the model, including muscle, but omitting vestibular and visual perception, shows that muscular feedback can stabilize the neck in all conditions. However, this model predicts excessive head rotations in conditions with trunk rotation and in the slalom. Adding feedback of head rotational velocity sensed by the semicircular canals effectively reduces head rotations at mid-frequencies. Realistic head rotations at low frequencies are obtained by adding vestibular and visual feedback of head rotation based on the MSOM or SVC model or assuming perfect perception. The MSOM with full vision well captures all conditions, whereas the MSOM excluding vision well captures all conditions without vision. The SVC provides two estimates of verticality, with a vestibular estimate SVC, which is highly effective in controlling head verticality, and an integrated vestibular/visual estimate SVC which can complement SVC in conditions with vision. As expected, in the sickening drive, SI models imprecisely estimate verticality, resulting in sensory conflict and postural instability.
CONCLUSION
The results support the validity of SI models in postural stabilization, where both MSOM and SVC provide credible results. The results in the sickening drive show imprecise sensory integration to enlarge head motion. This uniquely links the sensory conflict theory and the postural instability theory in motion sickness causation.
PubMed: 38073639
DOI: 10.3389/fneur.2023.1266345 -
Journal of Clinical Medicine Dec 2023Cardiovascular diseases are a group of disorders of heart and blood vessels which are the leading cause of death globally. They are also a very important cause of... (Review)
Review
Cardiovascular diseases are a group of disorders of heart and blood vessels which are the leading cause of death globally. They are also a very important cause of military unsuitability especially among military pilots. Some of the risk factors cannot be modified, but a large group of them can be modified by introducing healthy habits or behaviors, such as regular physical activity, quitting of tobacco smoking, cessation of harmful alcohol consumption, or stress avoidance. Specific occupational and environmental factors, such as acceleration, pressure changes, hypoxia, thermal stress, noise, vibration, prolonged sedentary posture, difficulties in moving the limbs, shifts, work shift irregularities, circadian dysrhythmia, variations in the microclimate, motion sickness, radiation, toxicological threats, occupational stress, emotional tension, highly demanding tasks especially during take-off and landing, predominance of intellectual over physical activity, and forced operation speed against time shortage are considered as characteristic for military personnel, especially military aircrews. They are of special concern as some of them are considered as potential CVD risk factors. The aim of this study was to discuss the influence of selected occupational and environmental factors (noise, altitude, hypoxia, acceleration forces, tobacco smoking, oral health, and stress) regarding their importance for CVD risk in military professionals and military aviators. The performed revision confirmed that they are exposed to certain characteristic conditions, which may influence the CVD risk but the number of solid scientific data regarding this subject are limited. There is a great need to perform complex studies on environmental and occupational risk factors for CVDs in military personnel and military aviators as well as how to minimize their influence to prolong the state of health and military suitability of this professional groups.
PubMed: 38068543
DOI: 10.3390/jcm12237492 -
Advanced Science (Weinheim,... Feb 2024Meclizine (Antivert, Bonine) is a first-generation H1 antihistamine used in the treatment of motion sickness and vertigo. Despite its wide medical use for over 70 years,...
Meclizine (Antivert, Bonine) is a first-generation H1 antihistamine used in the treatment of motion sickness and vertigo. Despite its wide medical use for over 70 years, its crystal structure and the details of protein-drug interactions remained unknown. Single-crystal X-ray diffraction (SC-XRD) is previously unsuccessful for meclizine. Today, microcrystal electron diffraction (MicroED) enables the analysis of nano- or micro-sized crystals that are merely a billionth the size needed for SC-XRD directly from seemingly amorphous powder. In this study, MicroED to determine the 3D crystal structure of meclizine dihydrochloride is used. Two racemic enantiomers (R/S) are found in the unit cell, which is packed as repetitive double layers in the crystal lattice. The packing is made of multiple strong N-H-Cl hydrogen bonding interactions and weak interactions like C-H-Cl and pi-stacking. Molecular docking reveals the binding mechanism of meclizine to the histamine H1 receptor. A comparison of the docking complexes between histamine H1 receptor and meclizine or levocetirizine (a second-generation antihistamine) shows the conserved binding sites. This research illustrates the combined use of MicroED and molecular docking in unraveling elusive drug structures and protein-drug interactions for precision drug design and optimization.
Topics: Meclizine; Molecular Docking Simulation; Electrons; Receptors, Histamine H1; Proteins; Histamine Antagonists
PubMed: 38044280
DOI: 10.1002/advs.202306435 -
PloS One 2023The increased sensation error between the surroundings and the driver is a major problem in driving simulators, resulting in unrealistic motion cues. Intelligent control...
The increased sensation error between the surroundings and the driver is a major problem in driving simulators, resulting in unrealistic motion cues. Intelligent control schemes have to be developed to provide realistic motion cues to the driver. The driver's body model incorporates the effects of vibrations on the driver's health, comfort, perception, and motion sickness, and most of the current research on motion cueing has not considered these factors. This article proposes a novel optimal motion cueing algorithm that utilizes the driver's body model in conjunction with the driver's perception model to minimize the sensation error. Moreover, this article employs H∞ control in place of the linear quadratic regulator to optimize the quadratic cost function of sensation error. As compared to state of the art, we achieve decreased sensation error in terms of small root-mean-square difference (70%, 61%, and 84% decrease in case of longitudinal acceleration, lateral acceleration, and yaw velocity, respectively) and improved coefficient of cross-correlation (3% and 1% increase in case of longitudinal and lateral acceleration, respectively).
Topics: Automobile Driving; Vibration; Cues; Acceleration; Algorithms; Accidents, Traffic
PubMed: 38032929
DOI: 10.1371/journal.pone.0290705 -
Current Therapeutic Research, Clinical... 2023Motion sickness (kinetosis) is a common and temporarily incapacitant ailment, manageable with behavioral as well as pharmacological measures.
A Combination of Gamma-Aminobutyric Acid, Glutamic Acid, Calcium, Thiamine, Pyridoxine, and Cyanocobalamin vs Ginger Extract in the Management of Chronic Motion Sickness: A Clinical Evaluation.
BACKGROUND
Motion sickness (kinetosis) is a common and temporarily incapacitant ailment, manageable with behavioral as well as pharmacological measures.
OBJECTIVE
To assess the effectiveness and safety of a combination of gamma-aminobutyric acid, glutamic acid, calcium, thiamine, pyridoxine, and cyanocobalamin (Group A) (n = 170) and extract of (ginger) (Group B) (n = 165) in the management of chronic complaints consistent with motion sickness.
METHODS
Both groups were tested according to the following end points, under self-paired as well as comparative study designs: reduction of ≥20 score points in the total motion sickness assessment questionnaire (MSAQ) score, percentage of patients presenting a reduction of the total MSAQ score, absolute MSAQ score reduction, physician's assessment scores, final overall assessment of study medication, and willingness to continue treatment. Safety was also evaluated.
RESULTS
There was a statistically significant better performance under both study designs for Group A ( = 0.05 using different statistical tests) in all end points. Both regimens were safe, with different neurological and gastrointestinal tolerability outcomes.
CONCLUSIONS
Group A and Group B regimens were effective and safe in the management of chronic complaints consistent with motion sickness and the Group A regimen was more effective than Group B.
PubMed: 38021267
DOI: 10.1016/j.curtheres.2023.100719