Motion sickness susceptibility

Effects of dynamic visual feedback system on seasickness

Motion sickness (MS) poses challenges for individuals affected, hindering their activities and travel. This study investigates the effect of a visual dynamic device, forming an artificial horizon plane, on symptoms and physiological changes induced by MS. This device consists of vertical light-emitting diodes whose illumination varies according to the boat's movements. Fifteen subjects with moderate-to-severe MS susceptibility were exposed to a seasickness simulator with and without the device. Symptoms were assessed immediately after exposure. Time spent in the simulator, heart rate, and temperature were also recorded. Symptom intensity at the end of the experience did not differ, but the time spent in the simulator was significantly longer with the device (+46%). Variations in heart rate were also observed. The device delays symptom onset and can be used as a tool against MS. Further research is needed to evaluate its effects, for example, during more prolonged exposure to MS-inducing stimuli.

Concussion can increase the risk of visually induced motion sickness

Concussion can lead to various symptoms such as balance problems, memory impairments, dizziness, and/or headaches. It has been previously suggested that during self-motion relevant tasks, individuals with concussion may rely heavily on visual information to compensate for potentially less reliable vestibular inputs and/or problems with multisensory integration. As such, concussed individuals may also be more sensitive to other visually-driven sensations such as visually induced motion sickness (VIMS). To investigate whether concussed individuals are at elevated risk of experiencing VIMS, we exposed participants with concussion (n = 16) and healthy controls (n = 15) to a virtual scene depicting visual self-motion down a grocery store aisle at different speeds. Participants with concussion were further separated into symptomatic and asymptomatic groups. VIMS was measured with the SSQ before and after stimulus exposure, and visual dependence, self-reported dizziness, and somatization were recorded at baseline. Results showed that concussed participants who were symptomatic demonstrated significantly higher SSQ scores after stimulus presentation compared to healthy controls and those who were asymptomatic. Visual dependence was positively correlated with the level of VIMS in healthy controls and participants with concussion. Our results suggest that the presence of concussion symptoms at time of testing significantly increased the risk and severity of VIMS. This finding is of relevance with regards to the use of visual display devices such as Virtual Reality applications in the assessment and rehabilitation of individuals with concussion.

Spatial anxiety contributes to the dizziness-related handicap of adults with peripheral vestibular disease

In subjects with peripheral vestibular disease and controls, we assessed: 1. The relationship between spatial anxiety and perceived stress, and 2. The combined contribution of spatial anxiety, spatial perspective-taking, and individual cofactors to dizziness-related handicap. 309 adults participated in the study (153 with and 156 without peripheral vestibular disease), including patients with bilateral vestibular deficiency, unilateral deficiency (evolution <3 or ≥3 months), Meniere's disease, and Benign Paroxysmal Positional Vertigo. Assessments included: general health, personal habits, spatial anxiety (3-domains), perceived stress, spatial perspective-taking, dizziness-related handicap (3-domains), unsteadiness, sleep quality, motion sickness susceptibility, trait anxiety/depression, state anxiety, depersonalization/derealization. After bivariate analyses, analysis of covariance was performed (p ≤ 0.05). Spatial anxiety was related to unsteadiness and perceived stress, with an inverse relationship with trait anxiety (ANCoVA, adjusted R2 = 0.27-0.30, F = 17.945-20.086, p < 0.00001). Variability on perspective-taking was related to vestibular disease, trait and state anxiety, motion sickness susceptibility, and age (ANCoVA, adjusted R2 = 0.18, F = 5.834, p < 0.00001). All domains of spatial anxiety contributed to the Physical domain of dizziness-related handicap, while the Navigation domain contributed to the Functional domain of handicap. Handicap variability was also related to unsteadiness, spatial perspective-taking, quality of sleep, and trait anxiety/depression (ANCoVA, adjusted R2 = 0.66, F = 39.07, p < 0.00001). Spatial anxiety is related to perceived stress in adults both with and without vestibular disease, subjects with trait anxiety rated lower on spatial anxiety. State anxiety and acute stress could be helpful for recovery after peripheral vestibular lesion. Spatial anxiety and perspective-taking contribute to the Physical and Functional domains of dizziness-related handicap, possibly because it discourages behavior beneficial to adaptation.

Investigation of the Correlation Between the Visually Induced Motion Sickness Susceptibility Questionnaire and the Turkish Motion Sickness Susceptibility Questionnaire

BACKGROUND AND OBJECTIVES

Visually induced motion sickness (VIMS) is a phenomenon similar to motion sickness frequently observed in users of visual technologies. The Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ), developed by Golding et al. (2006), is considered the most effective scale for assessing VIMS susceptibility levels. The main purpose of this study was to standardize the selection of participants for research conducted with virtual reality, especially motion sickness (MS) research. To achieve this, first, the Turkish version of the VIMSSQ was created to establish its validity and reliability, and subsequently, its correlation with the Turkish Motion Sickness Susceptibility Questionnaire Short form (HDDA), the expanded version of the Motion Sickness Susceptibility Questionnaire Short form (MSSQ), was examined. Subjects and.

METHODS

Linguistic equivalence assessment was obtained from ten experts by passing the VIMSSQ through the translation process. The VIMSSQ and the Turkish MSSQ forms were then administered to 49 subjects. This study statistically analyzed the validity and reliability of the VIMSSQ and its relationship with the MSSQ.

RESULTS

Results showed that the Turkish version of the original questionnaire is highly reliable (Cronbach alpha=0.843). There is a moderate statistically significant positive correlation between the total MSSQ scores and the subfactors of the VIMSSQ.

CONCLUSIONS

In this study, VIMSSQ was successfully adapted to Turkish, normative data demonstrated its validity, and all sub-factors were highly reliable. The Turkish version of the VIMSSQ can serve as a valuable tool for estimating individual susceptibility to VIMS.

Top-down control of vestibular inputs by the dorsolateral prefrontal cortex

The vestibular apparatus provides spatial information on the position of the head in space and with respect to gravity. Low-frequency sinusoidal galvanic vestibular stimulation (sGVS), a means of selectively changing the firing of vestibular afferents, induces a frequency-dependent perception of sway and, in some individuals, induces nausea. Given that vestibular afferents project to the insular cortex-which forms part of the vestibular cortex-and that the insula receives inputs from the dorsolateral prefrontal cortex (dlPFC), we tested the hypothesis that electrical stimulation of the dlPFC can modulate vestibular inputs. Sinusoidal electrical stimulation (± 2 mA, 0.08 Hz, 100 cycles) was delivered via surface electrodes over (1) the mastoid processes alone (sGVS), (2) electroencephalogram (EEG) site F4 (right dlPFC) and the nasion or (3) to each site concurrently (sGVS + dlPFC) in 23 participants. The same stimulation protocol was used in a separate study to investigate EEG site F3 (left dlPFC) instead of F4 in 13 participants. During sGVS, all participants reported perceptions of sway and 13 participants also reported nausea, neither sensation of which occurred as a result of dlPFC stimulation. Interestingly, when sGVS and dlPFC stimulations were delivered concurrently, vestibular perceptions and sensations of nausea were almost completely abolished. We conclude that the dlPFC provides top-down control of vestibular inputs and further suggests that dlPFC stimulation may provide a novel means of controlling nausea.

Evaluating proxies for motion sickness in rodent

Motions sickness (MS) occurs when the brain receives conflicting sensory signals from vestibular, visual and proprioceptive systems about a person's ongoing position and/or motion in relation to space. MS is typified by symptoms such as nausea and emesis and implicates complex physiological aspects of sensations and sensorimotor reflexes. Use of animal models has been integral to unraveling the physiological causality of MS. The commonly used rodents (rat and mouse), albeit lacking vomiting reflex, reliably display phenotypic behaviors of pica (eating of non-nutritive substance) and conditioned taste aversion (CTAver) or avoidance (CTAvoi) which utilize neural substrates with pathways that cause gastrointestinal malaise akin to nausea/emesis. As such, rodent pica and CTAver/CTAvoi have been widely used as proxies for nausea/emesis in studies dealing with neural mechanisms of nausea/emesis and MS, as well as for evaluating therapeutics. This review presents the rationale and experimental evidence that support the use of pica and CTAver/CTAvoi as indices for nausea and emesis. Key experimental steps and cautions required when using rodent MS models are also discussed. Finally, future directions are suggested for studying MS with rodent pica and CTAver/CTAvoi models.

The immersive virtual memory task: Assessing object-location memory in neurological patients using immersive virtual reality

TRIAL REGISTRATION

German Clinical Trials Register identifier: DRKS00024005.

Aged mice are less susceptible to motion sickness and show decreased efferent vestibular activity compared to young adults

INTRODUCTION

The efferent vestibular system (EVS) is a feedback circuit thought to modulate vestibular afferent activity by inhibiting type II hair cells and exciting calyx-bearing afferents in the peripheral vestibular organs. In a previous study, we suggested EVS activity may contribute to the effects of motion sickness. To determine an association between motion sickness and EVS activity, we examined the effects of provocative motion (PM) on c-Fos expression in brainstem efferent vestibular nucleus (EVN) neurons that are the source of efferent innervation in the peripheral vestibular organs.

METHODS

c-Fos is an immediate early gene product expressed in stimulated neurons and is a well-established marker of neuronal activation. To study the effects of PM, young adult C57/BL6 wild-type (WT), aged WT, and young adult transgenic Chat-gCaMP6f mice were exposed to PM, and tail temperature (Ttail ) was monitored using infrared imaging. After PM, we used immunohistochemistry to label EVN neurons to determine any changes in c-Fos expression. All tissue was imaged using laser scanning confocal microscopy.

RESULTS

Infrared recording of Ttail during PM indicated that young adult WT and transgenic mice displayed a typical motion sickness response (tail warming), but not in aged WT mice. Similarly, brainstem EVN neurons showed increased expression of c-Fos protein after PM in young adult WT and transgenic mice but not in aged cohorts.

CONCLUSION

We present evidence that motion sickness symptoms and increased activation of EVN neurons occur in young adult WT and transgenic mice in response to PM. In contrast, aged WT mice showed no signs of motion sickness and no change in c-Fos expression when exposed to the same provocative stimulus.

Heart Rate Variability Responses to Visually Induced Motion Sickness

Analysis of heart rate variability (HRV) can reveal a range of useful information regarding the dynamics of the autonomic nervous system (ANS). It is considered a robust and reliable tool to understand even some subtle changes in ANS activity. Here, we study the "hidden" characteristic changes in HRV during visually induced motion sickness; using nonlinear analytical methods, supplemented by conventional time- and frequency-domain analyses. We computed HRV from electrocardiograms (ECG) of 14 healthy participants measured at baseline and during nausea. Primarily hypothesizing evident differences in measures of physiologic complexity (SampEn; sample entropy, FuzzyEn; fuzzy entropy), chaos (LLE; largest Lyapunov exponent) and Poincaré/Lorenz (CSI; cardiac sympathetic activity, CVI; cardiac vagal index) between the two states. We found that during nausea, participants showed a markedly higher degree of regularity (SampEn, p = 0.0275; FuzzyEn, p = 0.0006), with a less chaotic ANS response (LLE, p = 0.0004). CSI significantly increased during nausea compared to baseline (p = 0.0005), whereas CVI did not appear to be statistically different between the two states (p = 0.182). Our findings suggest that motion sickness-induced ANS perturbations may be quantifiable via nonlinear HRV indices. These findings have implications for understanding the malaise of motion sickness and in turn, aid development of therapeutic interventions to relieve motion sickness symptoms.Clinical relevance- The study suggests potential indices of physiologic complexity and chaos that may be useful in monitoring motion sickness during clinical studies.

Sex-disease dimorphism underpins enhanced motion sickness susceptibility in primary adrenal insufficiency: a cross-sectional observational study

Environmental motion can induce physiological stress and trigger motion sickness. In these situations, lower-than-normal levels of adrenocorticotropic hormone (ACTH) have been linked with increased susceptibility to motion sickness in healthy individuals. However, whether patients with primary adrenal insufficiency, who typically have altered ACTH levels compared to the normal population, exhibit alterations in sickness susceptibility remains unknown. To address this, we recruited 78 patients with primary adrenal insufficiency and compared changes in the motion sickness susceptibility scores from 10 years prior to diagnosis (i.e. retrospective sickness rating) with the current sickness measures (post-diagnosis), using the validated motion sickness susceptibility questionnaire (MSSQ). Group analysis revealed that motion sickness susceptibility pre-diagnosis did not differ between controls and patients. We observed that following treatment, current measures of motion sickness were significantly increased in patients and subsequent analysis revealed that this increase was primarily in female patients with primary adrenal insufficiency. These observations corroborate the role of stress hormones in modulating sickness susceptibility and support the notion of a sexually dimorphic adrenal cortex as we only observed selective enhancement in females. A potential mechanism to account for our novel observation remains obscure, but we speculate that it may reflect a complex sex-disease-drug interaction.

Modified Egocentric Viewpoint for Softer Seated Experience in Virtual Reality

Users in a prolonged experience of virtual reality adopt a sitting position according to their task, as they do in the real world. However, inconsistencies in the haptic feedback from a chair they sit on in the real world and that which is expected in the virtual world decrease the feeling of presence. We aimed to change the perceived haptic features of a chair by shifting the position and angle of the users' viewpoints in the virtual reality environment. The targeted features in this study were seat softness and backrest flexibility. To enhance the seat softness, we shifted the virtual viewpoint using an exponential formula soon after a user's bottom contacted the seat surface. The flexibility of the backrest was manipulated by moving the viewpoint, which followed the tilt of the virtual backrest. These shifts make users feel as if their body moves along with the viewpoint; as a result, they would perceive pseudo-softness or flexibility consistently with the body movement. Based on subjective evaluations, we confirmed that the participants perceived the seat as being softer and the backrest as being more flexible than the actual ones. These results demonstrated that only shifting the viewpoint could change the participants' perceptions of the haptic features of their seats, although significant changes created strong discomfort.

Evaluation of effects of optokinetic and rotational stimuli with functional head impulse test (fHIT) in individuals with motion sickness

OBJECTIVES

To evaluate effects of optokinetic and rotational stimulus in individuals with and without motion sickness (MS) using fHIT.

METHODS

The study included subjects aged 18-40; 35 subjects with MS for MS group and 35 subjects without vertigo for control group. Percentage of the correct answer (% CA) with and without optokinetic stimulus (o-fHIT) in the frontal plane in the fHIT test was compared in both groups. In addition, both group subjects were seated on an ordinary rotating office chair. % CA was compared between groups by applying rotational fHIT (r-fHIT) test after the subjects were rotated randomly to the right and left and also simultaneously moved their heads in the vertical plane.

RESULTS

There was no significant difference in % CA in fHIT o-fHIT and r-fHIT in the control group. Both groups showed a significant difference in % CA for fHIT, o-fHIT, and r-fHIT for all SCCs (p < 0.05).

CONCLUSIONS

Since individuals with MS are affected by optokinetic and rotational stimuli, fHIT performed after these stimuli can be used as an objective confirming test for diagnosing MS.

Motion sickness susceptibility and visually induced motion sickness as diagnostic signs in Parkinson's disease

Postural instability and loss of vestibular and somatosensory acuity can be part of the signs encountered in Parkinson's Disease (PD). Visual dependency is described in PD. These modifications of sensory input hierarchy are predictors of motion sickness (MS). The aim of this study was to assess MS susceptibility and effects of real induced MS in posture. 63 PD patients, whose medication levels (levodopa) reflected the pathology were evaluated, and 27 healthy controls, filled a MS questionnaire; 9 PD patients and 43 healthy controls were assessed by posturography using virtual reality. Drug amount predicted visual MS (p=0.01), but not real induced MS susceptibility. PD patients did not experience postural instability in virtual reality, contrary to healthy controls. Since PD patients do not seem to feel vestibular stimulated MS, they may not rely on vestibular and somatosensory inputs during the stimulation. However, they feel visually induced MS more with increased levodopa drug effect. Levodopa amount can increase visual dependency. The strongest MS predictors must be studied in PD to better understand the effect of visual stimulation and its absence in vestibular stimulation.

Study of clinical correlation of motion sickness in patients with vestibular migraine

Objective

In this study, clinical data from vestibular migraine (VM) patients and healthy control populations were collected to analyze the clinical data of VM patients, especially the history of motion sickness, and to understand their clinical characteristics.

Methods

According to VM diagnostic criteria, 140 patients diagnosed with confirmed VM (cVM) and probable VM (pVM) who attended the outpatient and inpatient ward of Jiaxing First Hospital between August 2017 and June 2021, as well as 287 healthy check-ups in the health management center, were analyzed and compared in terms of age, gender, and previous history of motion sickness.

Results

A comparison of clinical data related to VM patients and the control population showed that there were more women in the VM group (P < 0.01) and that patients in the VM group were older (P < 0.05) and had a higher prevalence of history of motion sickness history (P < 0.01). Analysis after matching gender and age revealed that patients in the cVM group were older than those in the pVM group (P < 0.05), but the proportion of motion sickness was lower than in the pVM group (P < 0.05). The age of the patients in the cVM group was mainly distributed around 50 years of age, following a normal distribution, whereas the age distribution of the patients in the pVM group did not have a significant trend of age concentration and was distributed at all ages.

Conclusion

The history of motion sickness is significant in patients with VM and may be a potential suggestive factor for the diagnosis of VM.

Seasickness among Icelandic seamen

Introduction

The working environment abroad a ship is unique, with constant stimuli such as rolling of the vessel, noise, and vibration. Fishing industry is important for Icelandic economy, still the effect of seasickness-related symptoms on seamen´s health is not fully understood. Thus, the objective of this study is to explore the impact of seasickness-related symptoms, i.e., seasickness, seasickness symptoms and mal de débarquement on seaman´s health, and how their working environment may affect those factors.

Methods

Cross-sectional data was collected from 262 seamen answering questionnaire. Majority of the seamen participated while attending a compulsory course held by the Maritime Safety and Survival Training Centre. The majority of participants were men. A chi-square test was used to detect the difference between variables.

Results

The majority of seamen had experienced seasickness (87.8%) or mal de débarquement (85.8%). Having a history of tension headache (38.1%) and tinnitus (37.9%) was quite common. A total of 30.6% of the participants had been admitted to hospital once or more due to mishaps or accidents on land.

Discussion

Seasickness and seasickness symptoms together with mal de débarquement are common in Icelandic seamen. Working conditions at sea are demanding and seam to affect the seamen´s health both at sea and ashore, making further research needed.

Effect of Visually Induced Motion Sickness from Head-Mounted Display on Cardiac Activity

Head-mounted display (HMD) virtual reality devices can facilitate positive experiences such as co-presence and deep immersion; however, motion sickness (MS) due to these experiences hinders the development of the VR industry. This paper proposes a method for assessing MS caused by watching VR content on an HMD using cardiac features. Twenty-eight undergraduate volunteers participated in the experiment by watching VR content on a 2D screen and HMD for 12 min each, and their electrocardiogram signals were measured. Cardiac features were statistically analyzed using analysis of covariance (ANCOVA). The proposed model for classifying MS was implemented in various classifiers using significant cardiac features. The results of ANCOVA reveal a significant difference between 2D and VR viewing conditions, and the correlation coefficients between the subjective ratings and cardiac features have significant results in the range of -0.377 to -0.711 (for SDNN, pNN50, and ln HF) and 0.653 to 0.677 (for ln VLF and ln VLF/ln HF ratio). Among the MS classification models, the linear support vector machine achieves the highest average accuracy of 91.1% (10-fold cross validation) and has a significant permutation test outcome. The proposed method can contribute to quantifying MS and establishing viewer-friendly VR by determining its qualities.

Stroboscopic lighting with intensity synchronized to rotation velocity alleviates motion sickness gastrointestinal symptoms and motor disorders in rats

Motion sickness (MS) is caused by mismatch between conflicted motion perception produced by motion challenges and expected “internal model” of integrated motion sensory pattern formed under normal condition in the brain. Stroboscopic light could reduce MS nausea symptom via increasing fixation ability for gaze stabilization to reduce visuo-vestibular confliction triggered by distorted vision during locomotion. This study tried to clarify whether MS induced by passive motion could be alleviated by stroboscopic light with emitting rate and intensity synchronized to acceleration–deceleration phase of motion. We observed synchronized and unsynchronized stroboscopic light (SSL: 6 cycle/min; uSSL: 2, 4, and 8 cycle/min) on MS-related gastrointestinal symptoms (conditioned gaping and defecation responses), motor disorders (hypoactivity and balance disturbance), and central Fos protein expression in rats receiving Ferris wheel-like rotation (6 cycle/min). The effects of color temperature and peak light intensity were also examined. We found that SSL (6 cycle/min) significantly reduced rotation-induced conditioned gaping and defecation responses and alleviated rotation-induced decline in spontaneous locomotion activity and disruption in balance beam performance. The efficacy of SSL against MS behavioral responses was affected by peak light intensity but not color temperature. The uSSL (4 and 8 cycle/min) only released defecation but less efficiently than SSL, while uSSL (2 cycle/min) showed no beneficial effect in MS animals. SSL but not uSSL inhibited Fos protein expression in the caudal vestibular nucleus, the nucleus of solitary tract, the parabrachial nucleus, the central nucleus of amygdala, and the paraventricular nucleus of hypothalamus, while uSSL (4 and 8 cycle/min) only decreased Fos expression in the paraventricular nucleus of hypothalamus. These results suggested that stroboscopic light synchronized to motion pattern might alleviate MS gastrointestinal symptoms and motor disorders and inhibit vestibular-autonomic pathways. Our study supports the utilization of motion-synchronous stroboscopic light as a potential countermeasure against MS under abnormal motion condition in future.

Motion sickness and postural control among Danish adolescents

OBJECTIVE

Easily available clinical tests to evaluate postural control are needed. Furthermore, motion sickness (MS) and postural control are correlated. The aims of this study were to compare the internal validity of a set of clinical tests of postural control with the internal validity of static posturography and to evaluate possible associations between postural control and MS.

METHODS

We included healthy subjects from a primary school in Denmark who completed questionnaires about MS and underwent two rounds of clinical tests of postural control and static posturography using a Tetrax Interactive Balance System two weeks apart. For clinical tests of postural control, subjects were observed for up to 30 s standing on both legs, on one leg, on a pillow both with their eyes open and again with their eyes closed.

RESULTS

Twenty-one subjects were included: 71% males with an average age of 13.7 years. Agreement rates ranged from 62% to 95% between test and retest in clinical tests.; lowest for subjects standing on their non dominant leg with their eyes open and highest for subjects performing Romberg's test with their eyes closed along with subjects standing on a pillow with their eyes open. For several of these tests, almost all subjects were able to hold their balance for the full 30 s. Test-retesting using static posturography by Bland Altman plot showed datapoints scattered equally above and below the mean line indicating no systematic bias. Results of clinical tests and static posturography were not associated. MS was reported from 43% of subjects and a trend was observed with high sway scores from subjects suffering from MS. This was statistically insignificant.

CONCLUSIONS

Due to a ceiling effect, subjects achieved the same scores in both rounds of testing in several of the clinical tests, reducing the clinical importance of these tests. Compared to clinical tests, static posturography seemingly remains the superior method when it comes to evaluation of postural control, although not as easily applicable in a daily clinical setting. When comparing MS and postural control a trend was observed, indicating higher sway scores in subjects suffering from MS.

Biochemical analysis reveals the systematic response of motion sickness mice to ginger (Zingiber officinale) extract's amelioration effect

ETHNOPHARMACOLOGICAL RELEVANCE

As a common medicinal and edible plant, Zingiber officinale Roscoe (ginger) is often used for the prevention of motion sickness. However, the mechanism of its anti-motion sickness remains to be elucidated.

AIM OF THE STUDY

To explore novel treatment for motion sickness with less side effects, anti-motion sickness effect of ginger (Zingiber officinale) extract (GE) and the possible molecular mechanisms were investigated.

MATERIALS AND METHODS

The anti-motion sickness effect of ginger was evaluated through mice animal experimental models. Components of ginger that might contribute to the anti-motion sickness effect were analyzed by LC-MS/MS. Subsequently, biochemical analysis integrated with serum metabolomic profiling were performed to reveal the systematic response of motion sickness mice to ginger extract's amelioration effect.

RESULTS

Exhaustive swimming time of mice in the GE group reached 8.9 min, which was 52.2% longer than that in the model group. Motion sickness index scores and time taken traversing balance beam of mice in the GE group were decreased by 53.2% and 38.5%, respectively. LC-MS/MS analysis suggested that various active ingredients in GE, such as gingerol, ginger oil and terpenoids, might contribute to its appealing anti-motion sickness activity. Biochemical analysis revealed that GE can relieve motion sickness through reducing histamine and acetylcholine release in vestibular system, regulating fatty acid oxidation, sugar metabolism and bile acid metabolism in mice.

CONCLUSION

Gavage of mice with GE can effectively relieve the symptoms of autonomic nervous system dysfunction, improve the balance and coordination ability and ameliorate the ability to complete complex work after rotation stimulation. GE has attractive potential for development and utilization as novel anti-motion sickness food or drugs.

A New Vestibular Stimulation Mode for Motion Sickness With Emphatic Analysis of Pica

Motion sickness (MS) was frequently introduced for rodents in research work through passive motion that disturbed vestibular signals in the presence of visual and aleatory, proprioceptive inputs. Inducement of MS in this way causes conflicting signals that activate intermixed neural circuits representing multimodal stimulation. From reductionism, a lab setup to elicit rat MS via vestibular stimulation was configured in the present study for MS study in connection with dissection of the central vestibular component causally underlying MS. The individual animal was blinded to light with a custom-made restrainer, and positioned at an inclination of 30° for otolith organs to receive unusual actions by gravitoinertial vector. Following a 2-h double-axis (earth–vertical) rotation involving angular acceleration/deceleration, a suit of behaviors characterizing the MS was observed to be significantly changed including pica (eating non-nutritive substance like kaolin), conditioned taste avoidance and locomotion (p < 0.05). Notably, for the statistical hypothesis testing, the utility of net increased amount of kaolin consumption as independent variables in data processing was expounded. In addition, Fos-immunostained neurons in vestibular nucleus complex were significantly increased in number, suggesting the rotation-induced MS was closely related to the vestibular activation. In conclusion, our work indicated that the present setup could effectively elicit the MS by disturbing vestibular signals in rat in the context of well-controlled proprioceptive inputs and lack of visual afference.

Role of Swiprosin-1/EFHD2 as a biomarker in the development of chronic diseases

Swiprosin-1 or EFHD2, is a Ca²⁺ binding actin protein and its expression has been shown to be distinct in various cell types. The expression of swiprosin-1 is upregulated during the activation of immune cells, epithelial and endothelial cells. The expression of swiprosin-1 is regulated by diverse signaling pathways that are contingent upon the specific type of cells. The aim of this review is to summarize and provide an overview of the role of swiprosin-1 in pathophysiological conditions of cancers, cardiovascular diseases, diabetic nephropathy, neuropsychiatric diseases, and in the process of inflammation, immune response, and inflammatory diseases. Novel approaches for the targeting of swiprosin-1 as a biomarker in the early detection and prevention of various development of chronic diseases are also explored.

Expansion to the Motion Sickness Susceptibility Questionnaire-Short Form: A Cross-Sectional Study

Background and Objectives

The primary objective of this study is to investigate the necessity of questioning virtual reality systems in the motion sickness susceptibility questionnaire (MSSQ)-short form. The secondary objective of this study is to determine the validity and reliability of the Turkish version of the MSSQ-short form, with proven validity and reliability.

Subjects and Methods

In the questionnaire form, for which expert opinion was obtained to maintain linguistic equivalence, the virtual reality items were added to the questionnaire. The questionnaire was then administered to 297 individuals. The results were statistically analyzed with and without these virtual reality items for validity and reliability.

Results

After the addition of the virtual reality items, the reliability of the questionnaire was found to be quite high (Cronbach’s alpha r=0.912). The norm values between the original MSSQ-short form (12.9±9.9) and the Turkish MSSQ-short form (13.8±12.9) were found to be consistent.

Conclusions

Motion sickness symptoms can occur not only during movement, but also with indirect stimulus. Our findings suggest that adding virtual reality items to the original form is important in long term practical applications. Our results show that the Turkish version of the original questionnaire is quite reliable. Submission of the MSSQ-short form in Turkish will be useful for documentation and will also encourage further research in this area.

Changes in Electroencephalography Activity of Sensory Areas Linked to Car Sickness in Real Driving Conditions

Car sickness is a major concern for car passengers, and with the development of autonomous vehicles, increasing numbers of car occupants are likely to be affected. Previous laboratory studies have used EEG measurements to better understand the cerebral changes linked to symptoms. However, the dynamics of motion in labs/simulators differ from those of a real car. This study sought to identify specific cerebral changes associated with the level of car sickness experienced in real driving conditions. Nine healthy volunteers participated as front passengers in a slalom session inducing lateral movements at very low frequency (0.2 Hz). They were continuously monitored via EEG recordings and subjectively rated their level of symptoms after each slalom, using a 5-point likert scale. Car-sickness symptoms evolved concomitantly with changes in theta and alpha power in the occipital and parietal areas. These changes may reflect altered sensory integration, as well as a possible influence of sleepiness mitigating symptoms.

The potential use of virtual reality in vestibular rehabilitation of motion sickness

OBJECTIVE

Motion sickness (MS) can be triggered by direct or indirect stimuli due to mismatches in the visual-vestibular autonomic pathways. Various studies in the literature have shown that virtual reality technologies can generate provocative stimuli for MS. Therefore, our primary aim is to investigate the usability of virtual reality systems in MS rehabilitation METHODS: 20 normal and 19 MS patients were included. A total of six virtual reality rehabilitation sessions (VRrs) with a game called "Roller Coaster Dreams" playable via PlayStation VR Head Mounted Display were applied thrice a week for 2 weeks, or twice a week for 3 weeks. Participants were evaluated at the pre-rehabilitation phase twice and after third and sixth rehabilitation sessions with the sensory organization test (SOT). The effectiveness of the rehabilitation program was statistically analyzed by comparing the results of SOTs.

RESULTS

All SOT results of the patient group were compared each other to evaluate the effectiveness of rehabilitation. According to the post-hoc comparisons, a statistically significant difference was found between the 1st, 2nd, 3rd, and 4th SOT- Equilibrium Scores; Condition 2 (p = 0.043), Condition 3 (p = 0.006), Condition 4 (p = 0.031), Condition 5 (p = 0.002) and Condition 6 (p = 0.040). There is no difference obtained in Condition 1 (p > 0.05). The Equilibrium Scores of SOT 3rd and SOT 4th were similar and 4th SOT-Equilibrium Scores were the highest among all SOT measurements. The results show that while the first three sessions were accepted as an orientation and adaptation sessions, 4^th, 5^thand 6^th sessions are habilitation sessions.

CONCLUSIONS

VR proved to be significantly effective and useful for MS rehabilitation. Additionally, observations indicated that using VR makes rehabilitation fun, increases the efficiency of the process, and reduces the risk of inadaptability to exercise.

Idiosyncratic multisensory reweighting as the common cause for motion sickness susceptibility and adaptation to postural perturbation

Numerous empirical and modeling studies have been done to find a relationship between postural stability and the susceptibility to motion sickness (MS). However, while the demonstration of a causal relationship between postural stability and the susceptibility to MS is still lacking, recent studies suggest that motion sick individuals have genuine deficits in selecting and reweighting multimodal sensory information. Here we investigate how the adaptation to changing postural situations develops and how the dynamics in multisensory integration is modulated on an individual basis along with MS susceptibility. We used a postural task in which participants stood on a posturographic platform with either eyes open (EO) or eyes closed (EC) during three minutes. The platform was static during the first minute (baseline phase), oscillated harmonically during the second minute (perturbation phase) and returned to its steady state for the third minute (return phase). Principal component (PC) analysis was applied to the sequence of short-term power density spectra of the antero-posterior position of the center of pressure. Results showed that the less motion-sick a participant is, the more similar is his balance between high and low frequencies for EO and EC conditions (as calculated from the eigenvector of the first PC). By fitting exponential decay models to the first PC score in the return phase, we estimated, for each participant in each condition, the sluggishness to return to the baseline spectrum. We showed that the de-adaptation following platform oscillation depends on the susceptibility to MS. These results suggest that non motion-sick participants finely adjust their spectrum in the perturbation phase (i.e. reweighting) and therefore take longer to return to their initial postural control particularly with eyes closed. Thus, people have idiosyncratic ways of doing sensory reweighting for postural control, these processes being tied to MS susceptibility.

Effect of Standardized Yelling on Subjective Perception and Autonomic Nervous System Activity in Motion Sickness

This study investigated the effects of yelling intervention on symptoms and autonomic responses in motion sickness. Forty-two healthy participants were recruited, and they participated in Coriolis stimulation, a technique for inducing motion sickness. The experimental procedure comprised five 1-min rotating stimuli with 1-min rest after each stimulus. Then, the symptom severity was assessed using the Motion Sickness Symptom Rating (MSSR). The d2 Test of Attention scores and cardiovascular responses were recorded before and after Coriolis stimulation. The electrocardiogram results were documented to analyze heart rate variability (HRV). During Coriolis stimulus, the participants were required to yell 5–8 times in the experimental trial, and to keep quiet for each minute of rotation in the control trial. The yelling intervention significantly reduced the MSSR score (p < 0.001). Nevertheless, it did not significantly affect the d2 Test of Attention scores. Yelling while rotating did not significantly affect the heart rate nor blood pressure. However, it decreased the normalized low frequency of HRV (p = 0.036). Moreover, it improved motion sickness, but its effect on attention was not evident. Motion sickness could significantly affect cardiovascular responses and HRV. However, yelling did not affect cardiovascular response, and it reduced sympathetic nervous system activity.

Anxiety and Motion Sickness Susceptibility May Influence the Ability to Update Orientation in the Horizontal Plane of Healthy Subjects

Few studies have evaluated the influence of idiosyncrasies that may influence the judgment of space-time orientation after passive motion. We designed a study to assess the influence of anxiety/depression (which may distort time perception), motion sickness susceptibility (which has been related to vestibular function, disorientation, and to the velocity storage mechanism), and personal habits on the ability to update orientation, after passive rotations in the horizontal plane. Eighty-one healthy adults (22–64 years old) accepted to participate. After they completed an in-house general health/habits questionnaire, the short Motion Sickness Susceptibility Questionnaire, the Hospital Anxiety and Depression Scale (HADS), the Pittsburgh Sleep Quality Index, and the short International Physical Activity Questionnaire, they were exposed to 10 manually driven whole-body rotations (45°, 90°, or 135°), in a square room, with distinctive features on the walls, while seated in the normal upright position, unrestrained, with noise-attenuating headphones and blindfolded. After each rotation, they were asked to report which wall or corner they were facing. To calculate the error of estimation of orientation, the perceived rotation was subtracted from the actual rotation. Multivariate analysis showed that the estimation error of the first rotation was strongly related to the results of the orientation test. The magnitude and the frequency of estimation errors of orientation were independently related to HADS anxiety sub-score and to adult motion sickness susceptibility, with no influence of age, but a contribution from the interaction of the use of spectacles, the quality of sleep and sex. The results suggest that idiosyncrasies may contribute to the space-time estimation of passive self-motion, with influence from emotional traits, adult motion sickness susceptibility, experience, and possibly sleep quality.

Head Impulse Test Paradigm and Suppression Head Impulse Test Paradigm in Individuals With and Without Motion Sickness

Purpose This study aimed to assess the vestibuloocular reflex (VOR) gain using both the Head Impulse Test Paradigm (HIMP) and Suppressive Head Impulse Test Paradigm (SHIMP) in individuals with motion sickness. Method Fifty eight participants (58 females) in the age range of 18-25 years were recruited for the study. The participants were divided into two groups, Group A had 29 participants with no motion sickness, and Group B consisted of 29 individuals who had motion sickness. All the participants underwent HIMP and SHIMP testing. Results None of the participants had a presence of saccades in the HIMP technique, and all the participants in both the groups had anticompensatory saccades in SHIMP technique. Also, there was no difference in VOR gain or VOR gain asymmetry between individuals with and without motion sickness using HIMP and SHIMP Techniques. Conclusions The results of the study show no differences in VOR gain between individuals with and without motion sickness. It has been reported that only low frequencies trigger the motion sickness. Since the Video Head Impulse Test assesses the high frequency, it may not be an ideal technique to evaluate the vestibular system in individuals with motion sickness.

Correlation between anxiety and chronic motion sensitivity

BACKGROUND

Chronic motion sensitivity (CMS) is a combination of autonomic symptoms provoked by exposure to motion. The correlation between anxiety and CMS is not yet well understood.

OBJECTIVES

1) To compare median anxiety levels between young adults with and without CMS. 2) To examine the effect of anxiety on postural stability with immersion virtual reality. 3) To compare anxiety levels between sexes.

METHODS

Participants included 60 adults (20-40 years), with and without CMS. After determining their current and general anxiety levels, postural stability was measured.

RESULTS

There were significant differences in median (minimum, maximum) state- and trait-anxiety scores between participants with and without CMS, but no significant differences in median state- and trait-anxiety scores between males and females with CMS. There was a significant inverse relationship between state- and trait-anxiety scores and postural stability (ρ= -0.28, p = 0.03, and ρ= -0.32, p = 0.01, respectively). The stepwise regression analysis showed the Motion Sickness Susceptibility Questionnaire-Short Form score to be the only variable contributing significantly to postural stability (R2 = 26.2%; t = -4.5, p <  0.001).

CONCLUSIONS

Young adults with CMS are more anxious, although anxiety does not contribute to postural stability in this group. Anxiety levels do not appear to differ between young adult males and females with CMS.

Motion sickness and sense of presence in a virtual reality environment developed for manual wheelchair users, with three different approaches

Visually Induced Motion Sickness (VIMS) is a bothersome and sometimes unsafe experience, frequently experienced in Virtual Reality (VR) environments. In this study, the effect of up to four training sessions to decrease VIMS in the VR environment to a minimal level was tested and verified through explicit declarations of all 14 healthy participants that were recruited in this study. Additionally, the Motion Sickness Assessment Questionnaire (MSAQ) was used at the end of each training session to measure responses to different aspects of VIMS. Total, gastrointestinal, and central motion sickness were shown to decrease significantly by the last training session, compared to the first one. After acclimatizing to motion sickness, participants' sense of presence and the level of their motion sickness in the VR environment were assessed while actuating three novel and sophisticated VR systems. They performed up to four trials of the Illinois agility test in the VR systems and the real world, then completed MSAQ and Igroup Presence Questionnaire (IPQ) at the end of each session. Following acclimatization, the three VR systems generated relatively little motion sickness and high virtual presence scores, with no statistically meaningful difference among them for either MSAQ or IPQ. Also, it was shown that presence has a significant negative correlation with VIMS.

Control of a virtual vehicle influences postural activity and motion sickness in pre-adolescent children

Among adults, persons in control of a vehicle (i.e., drivers) are less likely to experience motion sickness compared to persons in the same vehicle who do not control it (i.e., passengers). This "driver-passenger effect" is well-known in adults, but has not been evaluated in children. Using a yoked-control design with seated pre-adolescent children, we exposed dyads to a driving video game. In each dyad, one child (the driver) drove the virtual vehicle. Their performance was recorded, and later shown to the other child (the passenger). Thus, visual motion stimuli were identical for the members of each dyad. During exposure to the video game, we monitored the quantitative kinematics of head and torso movements. Participants were instructed to discontinue participation immediately if they experienced any symptoms of motion sickness, however mild. Accordingly, the movements that we recorded preceded the onset of motion sickness. Results revealed that Passengers (73.08%) were more likely than Drivers (42.31%) to state that they were motion sick. Drivers tended to move more than passengers, and with a greater degree of multifractality. The magnitude of movement was greater among participants who later reported motion sickness than among those who did not. In addition, for the multifractality of movement a statistically significant interaction revealed that postural precursors of motion sickness differed qualitatively between Drivers and Passengers. Overall, the results reveal that control of a virtual vehicle reduces the risk of motion sickness among pre-adolescent children.

Suscetibilidade à cinetose em crianças de oito a onze anos

RESUMO A cinetose se caracteriza pela intolerância ao movimento, resultante de um conflito sensorial entre os sistemas visual, proprioceptivo e vestibular. Na população infantil, a cinetose é frequente, porém o difícil diagnóstico acaba subestimando a prevalência nesse grupo específico. As alterações vestibulares pediátricas têm importante influência no desenvolvimento infantil. O objetivo do artigo foi analisar a suscetibilidade à cinetose em crianças e verificar possíveis fatores associados, bem como identificar diferenças entre as respostas, quando comparados os sexos, as faixas etárias e a autopercepção dos pais. Trata-se de um estudo transversal. A amostra de conveniência consecutiva foi constituída por crianças de ambos os sexos, com idade entre oito e onze anos. Para avaliar a suscetibilidade à cinetose, foi aplicado o motion sickness questionnaire short form (MSSQ), realizado individualmente com cada criança. A análise estatística foi realizada por meio do SPSS Versão v.21. Adotou-se nível de significância de 0,05. Utilizaram-se os testes estatísticos Kolmogorov-Smirnov; T de Student; Anova e teste de Friedman. Ao total, foram analisadas 223 crianças. Observou-se que 89,7% das crianças avaliadas eram suscetíveis à cinetose. Houve diferença significativa na comparação da suscetibilidade à cinetose entre os sexos, sendo as meninas, mais suscetíveis em relação aos meninos (p=0,001). Na comparação entre as faixas etárias, não houve significância estatística. Crianças com onze anos apresentaram maior suscetibilidade à cinetose. Houve diferença nas respostas relatadas pelas crianças e pais sobre a suscetibilidade das crianças à cinetose.

Evaluation of a Human–Machine Interface for Motion Sickness Mitigation Utilizing Anticipatory Ambient Light Cues in a Realistic Automated Driving Setting

Motion sickness (MS) is a syndrome associated with symptoms like nausea, dizziness, and other forms of physical discomfort. Automated vehicles (AVs) are potent at inducing MS because users are not adapted to this novel form of transportation, are provided with less information about the own vehicle’s trajectory, and are likely to engage in non-driving related tasks. Because individuals with an especially high MS susceptibility could be limited in their use of AVs, the demand for MS mitigation strategies is high. Passenger anticipation has been shown to have a modulating effect on symptoms, thus mitigating MS. To find an effective mitigation strategy, the prototype of a human–machine interface (HMI) that presents anticipatory ambient light cues for the AV’s next turn to the passenger was evaluated. In a realistic driving study with participants (N = 16) in an AV on a test track, an MS mitigation effect was evaluated based on the MS increase during the trial. An MS mitigation effect was found within a highly susceptible subsample through the presentation of anticipatory ambient light cues. The HMI prototype was proven to be effective regarding highly susceptible users. Future iterations could alleviate MS in field settings and improve the acceptance of AVs.

Pyruvate accumulation may contribute to acceleration-induced impairment of physical and cognitive abilities: an experimental study

Background: Fatigue can be induced after acceleration exposure, however its mechanism is still unclear. The aim of the present study was to examine whether metabolites’ changes can decrease cognitive and physical function after acceleration. Methods: Graybiel scale and Fatigue Self-rating scale were used to assess the seasickness and fatigue degrees of 87 male seafarers respectively after sailing. To test the effect of pyruvate on cognitive and physical functions, five different doses of pyruvate were administrated into rats. Insulin can reduce the accumulation of pyruvate. To observe the insulin effect on pyruvate, cognitive and physical functions after acceleration, insulin administration or treatment of promoting insulin secretion was used. Physical and cognitive functions were assessed using open field test (OFT), morris water maze (MWM) and loaded swimming test (LST) in animals. Results: Physical and cognitive abilities were decreased obviously, and serum pyruvate increased mostly in human and rats after acceleration. Compared with vehicle group, physical and cognitive abilities were significantly decreased after pyruvate administration. Besides, we found a significant decline in adenosine triphosphate (ATP) concentration and pyruvate dehydrogenase (PDH) activity in the hippocampus, prefrontal cortex, liver, and muscle of rats treated with acceleration or pyruvate injection, while insulin administration or treatment of promoting insulin secretion markedly alleviated this decline and the impairment of physical and cognitive abilities, compared with the control group. Conclusion: Our results indicate that pyruvate has a negative effect on physical and cognitive abilities after acceleration. Insulin can inhibit pyruvate accumulation and cognitive and physical function after acceleration exposure.

The Relationship Between Vestibular Migraine and Motion Sickness Susceptibility

OBJECTIVES

To determine the relationship between vestibular migraine (VM) and motion sickness (MoS) susceptibility and their comorbidity in a large student population, and to assess whether experiencing MoS is associated with higher susceptibility for VM.

METHODS

Surveys including Motion Sickness Susceptibility Questionnaire (MSSQ) and questions assessing migraine-related symptoms as well as family history of motion sickness and migraine headache were distributed to the university undergraduate students through Facebook and email. Diagnosis of definite VM (dVM) was based on the criteria of the International Classification of Headache Disorders.

RESULTS

Of 277 survey responders, 148 (53%) were found to be susceptible to MoS in which 74 (50%) met the criteria for dVM. Only childhood MSSQ score was significantly higher in participants with dVM compared with those without dVM (25.78 ± 15.89 versus 20.77 ± 14.28, p = 0.04); however, its significance faded out by regression analysis. Multivariate logistic regression showed having 1st degree relative with migraine headache (p = 0.02), neck stiffness (p = 0.001), and sinus pain, facial pressure, or headache with wind exposure (p = 0.02) to be independently associated with presence of dVM in MoS subjects.

CONCLUSIONS

Though participants with MoS and dVM had significantly greater rates of migraine-related symptoms and family history of migraine headache compared with those with MoS only, childhood and adulthood MSSQ scores were similar. This and the high prevalence of dVM in our MoS cohort may suggest an existing association between MoS susceptibility and VM.

Older Drivers’ Motion and Simulator Sickness before and after Automated Vehicle Exposure

Older drivers desire independence in mobility, and automated vehicles hold plausible opportunities to realize this goal. Motion sickness (automated shuttle exposure) or simulator sickness (automated driving simulator exposure) may affect acceptance of these technologies. This study investigated the onset of motion and simulator sickness in older drivers (mean age = 74.29, SD = 5.96; female = 54%) after exposure to an automated shuttle and automated driving simulator and assessed age and sex as determinants of motion and/or simulator sickness. Using a repeated measures design, 104 older drivers were randomly allocated to the shuttle and simulator. Baseline, as well as post exposures, were measured using the Motion Sickness Assessment Questionnaire (domains: sweatiness, queasiness, dizziness, nauseousness). Older drivers who were exposed to the simulator show a statistically significant increase in simulator sickness symptoms across the four domains compared to the same group being tested in the shuttle. No age and sex differences were detected within the groups and no participants dropped out of the study due to motion or simulator sickness. The automated shuttle and simulator hold plausible opportunities for continued exposure of older drivers to these technologies, as long as motion or driving simulator sickness protocols are used properly.

Toward Predicting Motion Sickness Using Virtual Reality and a Moving Platform Assessing Brain, Muscles, and Heart Signals

Motion sickness (MS) and postural control (PC) conditions are common complaints among those who passively travel. Many theories explaining a probable cause for MS have been proposed but the most prominent is the sensory conflict theory, stating that a mismatch between vestibular and visual signals causes MS. Few measurements have been made to understand and quantify the interplay between muscle activation, brain activity, and heart behavior during this condition. We introduce here a novel multimetric system called BioVRSea based on virtual reality (VR), a mechanical platform and several biomedical sensors to study the physiology associated with MS and seasickness. This study reports the results from 28 individuals: the subjects stand on the platform wearing VR goggles, a 64-channel EEG dry-electrode cap, two EMG sensors on the gastrocnemius muscles, and a sensor on the chest that captures the heart rate (HR). The virtual environment shows a boat surrounded by waves whose frequency and amplitude are synchronized with the platform movement. Three measurement protocols are performed by each subject, after each of which they answer the Motion Sickness Susceptibility Questionnaire. Nineteen parameters are extracted from the biomedical sensors (5 from EEG, 12 from EMG and, 2 from HR) and 13 from the questionnaire. Eight binary indexes are computed to quantify the symptoms combining all of them in the Motion Sickness Index (I _MS ). These parameters create the MS database composed of 83 measurements. All indexes undergo univariate statistical analysis, with EMG parameters being most significant, in contrast to EEG parameters. Machine learning (ML) gives good results in the classification of the binary indexes, finding random forest to be the best algorithm (accuracy of 74.7 for I _MS ). The feature importance analysis showed that muscle parameters are the most relevant, and for EEG analysis, beta wave results were the most important. The present work serves as the first step in identifying the key physiological factors that differentiate those who suffer from MS from those who do not using the novel BioVRSea system. Coupled with ML, BioVRSea is of value in the evaluation of PC disruptions, which are among the most disturbing and costly health conditions affecting humans.

Motion sickness diagnostic criteria: Consensus document of the classification committee of the Bárány society

We present diagnostic criteria for motion sickness, visually induced motion sickness (VIMS), motion sickness disorder (MSD), and VIMS disorder (VIMSD) to be included in the International Classification of Vestibular Disorders. Motion sickness and VIMS are normal physiological responses that can be elicited in almost all people, but susceptibility and severity can be high enough for the response to be considered a disorder in some cases. This report provides guidelines for evaluating signs and symptoms caused by physical motion or visual motion and for diagnosing an individual as having a response that is severe enough to constitute a disorder.

   The diagnostic criteria for motion sickness and VIMS include adverse reactions elicited during exposure to physical motion or visual motion leading to observable signs or symptoms of greater than minimal severity in the following domains: nausea and/or gastrointestinal disturbance, thermoregulatory disruption, alterations in arousal, dizziness and/or vertigo, headache and/or ocular strain. These signs and/or symptoms occur during the motion exposure, build as the exposure is prolonged, and eventually stop after the motion ends. Motion sickness disorder and VIMSD are diagnosed when recurrent episodes of motion sickness or VIMS are reliably triggered by the same or similar stimuli, severity does not significantly decrease after repeated exposure, and signs/symptoms lead to activity modification, avoidance behavior, or aversive emotional responses.

   Motion sickness/MSD and VIMS/VIMSD can occur separately or together. Severity of symptoms in reaction to physical motion or visual motion stimuli varies widely and can change within an individual due to aging, adaptation, and comorbid disorders. We discuss the main methods for measuring motion sickness symptoms, the situations conducive to motion sickness and VIMS, and the individual traits associated with increased susceptibility. These additional considerations will improve diagnosis by fostering accurate measurement and understanding of the situational and personal factors associated with MSD and VIMSD.

The Evaluation of Virtual Reality Fire Extinguisher Training

The aim of this research was to explore trainees' perceptions and evaluation of Virtual Reality fire extinguisher training. Virtual Reality technology is being adopted by many industries for various purposes including safety training for safety critical industries. The future direction of Virtual Reality training requires an understanding of trainees' evaluation of it; this fact motivated this research. Data were collected from 85 participants using a questionnaire after the training. Observation notes were taken to provide a better understanding of the context. Qualitative research with a thematic analysis was used to analyze the data. The results of this analysis revealed that the most salient themes reflect on issues surrounding the realism of the Virtual Reality simulation, namely different emotional and bodily experiences during the training, while the benefits of the training (health, safety, environmental advantages, efficiency and convenience, repeatability and variety of scenarios) make it a good supplement. Nevertheless, improved realism is needed to make it more effective and enhance transfer and acceptance. This study encourages the consideration of important matters (such as realism and emotions) when using Virtual Reality for fire training. It also describes the positive perceptions of this type of training (repeatability of training, safety and environmental concerns).

Examining potential effects of arousal, valence, and likability of music on visually induced motion sickness

The present study investigated how valence, arousal, and subjective liking of music affect visually induced motion sickness (VIMS). VIMS is a common side effect when interacting with virtual environments, resulting in discomfort, dizziness, and/or nausea. Music has previously been shown to reduce VIMS, but the precise nature of this effect remains unknown. Eighty participants watched a video of a bicycle ride filmed from a first-person perspective. First, participants (n = 40) were randomly assigned to one of four groups that listened to pre-selected, classical music excerpts varying in valence and arousal (happy, peaceful, agitated, sad) while watching the video. Second, the level of subjective liking of music was maximized by asking participants to select their favourite music (n = 20), which was then played during the video. A control group (n = 20) watched the video without music. VIMS was measured using the Fast Motion Sickness Scale (FMS) and the Simulator Sickness Questionnaire (SSQ). No effects of valence or arousal on VIMS symptoms were found. Instead, we found that VIMS was significantly reduced when music liking was maximized: Participants who listened to their favourite music reported less VIMS compared to those who did not listen to music at all or to pre-selected music that they liked less. Music that is highly liked can, under certain circumstances, successfully reduce VIMS. These effects appear to be independent of the valence and arousal characteristics of the music.

Exploring the Participant-Related Determinants of Simulator Sickness in a Physical Motion Car Rollover Simulation as Measured by the Simulator Sickness Questionnaire

Physical motion driving simulators serve as a valuable research and training tool. Since many simulator participants suffer from simulator sickness (SS), we aimed to gain a better understanding of participant-related variables that may influence its incidence and severity. The study involved a 2-min mobile-platform car rollover simulation conducted in a group of 100 healthy adult participants. SS was measured with the Simulator Sickness Questionnaire immediately before and after the simulation. We investigated how the symptomatology of SS varies with gender, as well as with participants’ previous experiences such as extra driving training or car accidents. Although many SS symptoms occurred already before the simulation, all the symptoms except burping had a significantly greater incidence and severity after the simulation. Before the simulation, men reported disorientation symptoms more often than women, while participants with prior experiences of extra driving training or car accidents scored significantly higher in three out of four Questionnaire components: nausea symptoms, oculomotor symptoms, and the total score. The study offers interesting insights into associations between SS and prior experiences observed by means of high-fidelity real-motion simulations. More research is needed to determine the nature of these associations and their potential usefulness, for example, in helping accident survivors to cope with the distressing or even potentially disabling psychological consequences of accidents.

Research on the Comfort of Vehicle Passengers Considering the Vehicle Motion State and Passenger Physiological Characteristics: Improving the Passenger Comfort of Autonomous Vehicles

Comfort is a significant factor that affects passengers’ choice of autonomous vehicles. The comfort of an autonomous vehicle is largely determined by its control algorithm. Therefore, if the comfort of passengers can be predicted based on factors that affect comfort and the control algorithm can be adjusted, it can be beneficial to improve the comfort of autonomous vehicles. In view of this, in the present study, a human-driven experiment was carried out to simulate the typical driving state of a future autonomous vehicle. In the experiment, vehicle motion parameters and the comfort evaluation results of passengers with different physiological characteristics were collected. A single-factor analysis method and binary logistic regression analysis model were used to determine the factors that affect the evaluation results of passenger comfort. A passenger comfort prediction model was established based on the bidirectional long short-term memory network model. The results demonstrate that the accuracy of the passenger comfort prediction model reached 84%, which can provide a theoretical basis for the adjustment of the control algorithm and path trajectory of autonomous vehicles.

A Preliminary Study: Central Vestibular Sensitivity Affects Motion Sickness Susceptibility through the Efficacy of the Velocity Storage Mechanism

Background/Objective: Slow-Phase Eye Velocity Time constant (SPEV TC) and Perceived Rotational Duration (PRD) are measurable objective outcomes of rotational chair step-velocity test. These two variables are dependent on the efficacy of the central velocity storage. If sensory conflict from the step-velocity of the rotational chair elicits motion sickness, the SPEV TC and PRD in individuals with varying susceptibility to motion sickness should be affected. We determined if Central Vestibular Sensitivity (CVS) characteristics differ among individuals with a range of Motion Sickness Susceptibility (MSS). Methods: Participants were allocated to two groups based on MSS (low and high) as identified on the short version of the Motion Sick Susceptibility Questionnaire (MSSQ-S). We evaluated the specific relationship between MSS and the characteristics of CVS through the SPEV TC and PRD from the step-velocity test. Results: Results showed significant differences in the PRD between these two groups. 180°/s Per-rotatory PRD is most significantly different (p = 0.005) followed by 50°/s post-rotatory PRD (CCW, p = 0.007; CW, p = 0.021) and log of 180°/s post-rotatory PRD (p = 0.042). Multiple regression analysis indicated that CCW post-rotatory PRD at 50°/s was a strong predictor of MSS. Conclusions: High MSS individuals were observed with elevated PRD in general, indirectly suggesting greater velocity storage efficiency, hence, greater CVS; CVS is therefore positively correlated with MSS. PRD could be a reliable clinical indicator of motion sick susceptibility and may help with the selection of personnel working in motion sick environments and with the verification of motion sickness therapeutic interventions.

VR motion sickness recognition by using EEG rhythm energy ratio based on wavelet packet transform

BACKGROUND AND OBJECTIVES

Virtual reality motion sickness (VRMS) is one of the main factors hindering the development of VR technology. At present, the VRMS recognition methods using electroencephalogram (EEG) signals have poor applicability to multiple subjects.

METHODS

Aiming at this dilemma, the wavelet packet transform (WPT), was used to propose a feature extraction method for EEG rhythm energy ratios of delta (δ), theta (θ), alpha (α), and beta (β) in this research. Moreover, VRMS was recognized by combining k-Nearest Neighbor classifier (k-NN), support vector machine (SVM) with polynomial kernel (polynomial-SVM) and radial basis function kernel (RBF-SVM), respectively. The method is that the raw EEG signals were de-noised by an elliptical band-pass filter and segmented by a fixed window, 7-level db4 WPT was performed on each EEG segment, and the wavelet packet energy ratios of delta, theta, alpha and beta rhythms from FP1, FP2, C3, C4, P3, P4, O1 and O2 channels were calculated and combined to form feature vectors for recognizing VRMS.

RESULTS

Under the condition of 4-s window size, the average VRMS recognition accuracy of polynomial-SVM for the single subject was 92.85%, and the VRMS recognition accuracy of 18 subjects was about 79.25%.

CONCLUSIONS

Compared with other VRMS recognition methods, this method does not only have a higher recognition accuracy to a single subject, but also have better applicability to multiple subjects. Meanwhile, when using the EEG four rhythm energy ratios of FP1, FP2, C3, C4, P3, P4, O1 and O2 channels as feature vectors, the polynomial-SVM achieved better VRMS recognition performance than the k-NN and RBF-SVM.

Effects of head motion on postural stability in healthy young adults with chronic motion sensitivity

Background

Motion sensitivity, or motion sickness, is common in modern vehicular and visually stimulating environments. Several studies have shown a relationship between motion sensitivity and decreased postural stability. We aimed to evaluate the effects of head motion (horizontal and vertical) on postural stability in healthy adults with and without chronic motion sensitivity (CMS).

Methods

Sixty healthy adult men and women (age, 20–40 years) with CMS (CMS group, n = 30) and without CMS (non-CMS group, n = 30) participated in the study. Postural stability was assessed during three conditions (static, horizontal head motion, and vertical head motion) using computerized dynamic posturography. Group and condition-related differences in equilibrium scores were evaluated.

Results

There was no significant group x condition interaction (F_2,114 = 0.9, partial ƞ² = 0.04, p = 0.35). However, significant condition-related differences in equilibrium scores were observed (F_2,114 = 26.4, partial ƞ² = 0.31, p < 0.001). Equilibrium scores were significantly worse in the horizontal and vertical head motion conditions compared to those in the static condition (p < 0.001), but were comparable in vertical and horizontal head motion conditions (p = 0.27).

Conclusions

Postural stability was lower in the horizontal and vertical conditions compared to the static condition. However, horizontal and vertical head motions had comparable effects on postural stability in both CMS and non-CMS groups, contrary to our expectations.

The effects of meclizine on motion sickness revisited

AIMS

Antihistamines make up the first line of treatments against motion-sickness. Still, their efficacy and specific mechanism have come into question. The aim of this study was to investigate the effect of meclizine on motion-sensitivity.

METHODS

This study was carried out as a triple-blinded randomized trial involving 12 healthy subjects who were exposed to (i) vestibular (VES), (ii) visual (VIS) and (iii) visual-vestibular (VIS+VES) stimulations in the roll plane. Subjects were divided into 2 groups by stratified randomization, receiving either meclizine or a placebo. Stimulations were carried out before, and after, drug administration, presented at 2 intensity levels of 14 and 28°/s² . Eye movements were tracked, and torsional slow-phase velocities, amplitudes and nystagmus beats were retrieved. Subjects initially graded for their motion-sickness susceptibility.

RESULTS

Susceptibility had no effect on intervention outcome. Despite large variations, repeated ANOVAS showed that meclizine led to a relative increase in torsional velocity compared to placebo during vestibular stimulation for both intensities: 2.36 (7.65) from -0.01 (4.17) during low intensities, and 2.61 (6.67) from -3.49 (4.76) during high. The visual-vestibular stimuli yielded a decrease during low acceleration, -0.40 (3.87) from 3.75 (5.62), but increased during high, 3.88 (6.51) from -3.88 (8.55).

CONCLUSIONS

Meclizine had an inhibitory effect on eye movement reflexes for low accelerations during VIS+VES trials. This indicates that meclizine may not primarily work through sensory-specific mechanisms, but rather on a more central level. Practically, meclizine shows promise in targeting motion-sickness evoked by everyday activities, but its use may be counterproductive in high-acceleration environments.

Gentle rocking movements during sleep in the elderly

Vestibular stimulation in the form of rocking movements could be a promising non‐pharmacological intervention for populations with reduced sleep quality, such as the elderly. We hypothesized that rocking movements influence sleep by promoting comfort. We assessed whether gentle rocking movements can facilitate the transition from wake to sleep, increase sleep spindle density and promote deep sleep in elderly people. We assessed self‐reported comfort using a pilot protocol including translational movements and movements along a pendulum trajectory with peak linear accelerations between 0.10 and 0.20 m/s². We provided whole‐night stimulation using the settings rated most comfortable during the pilot study (movements along a pendulum trajectory with peak linear acceleration of 0.15 m/s²). Sleep measures (polysomnography) of two baseline and two movement nights were compared. In our sample (n = 19; eight female; mean age: 66.7 years, standard deviation: 3 years), vestibular stimulation using preferred stimulation settings did not improve sleep. A reduction of delta power was observed, suggesting reduced sleep depth during rocking movements. Sleep fragmentation was similar in both conditions. We did not observe a sleep‐promoting effect using settings optimized to be comfortable. This finding could imply that comfort is not the underlying mechanism. At frequencies below 0.3 Hz, the otoliths cannot distinguish tilt from translation. Translational movement trajectories, such as used in previous studies reporting positive effects of rocking, could have caused sensory confusion due to a mismatch between vestibular and other sensory information. We propose that this sensory confusion might be essential to the sleep‐promoting effect of rocking movements described in other studies.

Virtual Reality Is Sexist: But It Does Not Have to Be

The aim of this study was to assess what drives gender-based differences in the experience of cybersickness within virtual environments. In general, those who have studied cybersickness (i.e., motion sickness associated with virtual reality [VR] exposure), oftentimes report that females are more susceptible than males. As there are many individual factors that could contribute to gender differences, understanding the biggest drivers could help point to solutions. Two experiments were conducted in which males and females were exposed for 20 min to a virtual rollercoaster. In the first experiment, individual factors that may contribute to cybersickness were assessed via self-report, body measurements, and surveys. Cybersickness was measured via the simulator sickness questionnaire and physiological sensor data. Interpupillary distance (IPD) non-fit was found to be the primary driver of gender differences in cybersickness, with motion sickness susceptibility identified as a secondary driver. Females whose IPD could not be properly fit to the VR headset and had a high motion sickness history suffered the most cybersickness and did not fully recover within 1 h post exposure. A follow-on experiment demonstrated that when females could properly fit their IPD to the VR headset, they experienced cybersickness in a manner similar to males, with high cybersickness immediately upon cessation of VR exposure but recovery within 1 h post exposure. Taken together, the results suggest that gender differences in cybersickness may be largely contingent on whether or not the VR display can be fit to the IPD of the user; with a substantially greater proportion of females unable to achieve a good fit. VR displays may need to be redesigned to have a wider IPD adjustable range in order to reduce cybersickness rates, especially among females.