Visually induced symptoms questionnaire (VISQ): A subjective evaluation method for biomedical effects induced by stereoscopic 3D video

The purpose of this paper is to establish an easy-to-use questionnaire for subjective evaluations of visually induced motion sickness (VIMS) and visual fatigue caused by stereoscopic 3D (s3D) images. We reviewed previously used questionnaires and extracted 51 important subjective evaluation items from them. We then recruited 251 participants to observe 3D images designed to easily induce sickness or visual fatigue, and we asked them to respond to the 51 items. As a result of exploratory factor analysis, four factors were extracted according to their factor loadings, and the number of items was reduced to 21. Further processing by confirmatory factor analysis led to the selection of 15 items. Comparing mean ratings for each factor before and after item reduction indicated that item reduction did not significantly affect the participant responses. Therefore, the 15-item Visually Induced Symptoms Questionnaire (VISQ), can be used to evaluate VIMS and s3D visual fatigue.

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.

Restricting the distribution of visual attention reduces cybersickness

This study investigated whether increased attention to the central or peripheral visual field can reduce motion sickness in virtual reality (VR). A recent study found that increased attention to the periphery during vection was correlated with lower self-reported motion sickness susceptibility, which suggests that peripheral attention might be beneficial for avoiding cybersickness. We tested this experimentally by manipulating visual attention to central vs. peripheral fields during VR exposure. We also measured attention to the periphery during vection and motion sickness susceptibility to attempt to replicate the previous results. In Experiment 1, task-relevant cues to target locations were provided in the central or peripheral field during navigation in VR, and we found no differences in motion sickness. In Experiment 2, attention to the center or periphery was manipulated with a dot-probe task during passive VR exposure, and we found that motion sickness was greater in the condition that required attention to the periphery. In both experiments, there was no correlation between baseline attentional allocation and self-reported motion sickness susceptibility. Our results demonstrate that restricting attention to the central visual field can decrease cybersickness, which is consistent with previous findings that cybersickness is greater with large FOV.

Emotions are associated with the genesis of visually induced motion sickness in virtual reality

Visually induced motion sickness (VIMS) is a well-known side effect of virtual reality (VR) immersion, with symptoms including nausea, disorientation, and oculomotor discomfort. Previous studies have shown that pleasant music, odor, and taste can mitigate VIMS symptomatology, but the mechanism by which this occurs remains unclear. We predicted that positive emotions influence the VIMS-reducing effects. To investigate this, we conducted an experimental study with 68 subjects divided into two groups. The groups were exposed to either positive or neutral emotions before and during the VIMS-provoking stimulus. Otherwise, they performed exactly the same task of estimating the time-to-contact while confronted with a VIMS-provoking moving starfield stimulation. Emotions were induced by means of pre-tested videos and with International Affective Picture System (IAPS) images embedded in the starfield simulation. We monitored emotion induction before, during, and after the simulation, using the Self-Assessment Manikin (SAM) valence and arousal scales. VIMS was assessed before and after exposure using the Simulator Sickness Questionnaire (SSQ) and during simulation using the Fast Motion Sickness Scale (FMS) and FMS-D for dizziness symptoms. VIMS symptomatology did not differ between groups, but valence and arousal were correlated with perceived VIMS symptoms. For instance, reported positive valence prior to VR exposure was found to be related to milder VIMS symptoms and, conversely, experienced symptoms during simulation were negatively related to subjects’ valence. This study sheds light on the complex and potentially bidirectional relationship of VIMS and emotions and provides starting points for further research on the use of positive emotions to prevent VIMS.

Chewing gum reduces visually induced motion sickness

Visually induced motion sickness (VIMS) is a common side-effect of exposure to virtual reality (VR). Its unpleasant symptoms may limit the acceptance of VR technologies for training or clinical purposes. Mechanical stimulation of the mastoid and diverting attention to pleasant stimuli-like odors or music have been found to ameliorate VIMS. Chewing gum combines both in an easy-to-administer fashion and should thus be an effective countermeasure against VIMS. Our study investigated whether gustatory-motor stimulation by chewing gum leads to a reduction of VIMS symptoms. 77 subjects were assigned to three experimental groups (control, peppermint gum, and ginger gum) and completed a 15-min virtual helicopter flight, using a VR head-mounted display. Before and after VR exposure, we assessed VIMS with the Simulator Sickness Questionnaire (SSQ), and during the virtual flight once every minute with the Fast Motion Sickness Scale (FMS). Chewing gum (peppermint gum: M = 2.44, SD = 2.67; ginger gum: M = 2.57, SD = 3.30) reduced the peak FMS scores by 2.05 (SE = 0.76) points as compared with the control group (M = 4.56, SD = 3.52), p < 0.01, d = 0.65. Additionally, taste ratings correlated slightly negatively with both the SSQ and the peak FMS scores, suggesting that pleasant taste of the chewing gum is associated with less VIMS. Thus, chewing gum may be useful as an affordable, accepted, and easy-to-access way to mitigate VIMS in numerous applications like education or training. Possible mechanisms behind the effect are discussed.

The relationship between postural stability and cybersickness: It's complicated - An experimental trial assessing practical implications of cybersickness etiology

Virtual reality (VR) is known to cause cybersickness, and studies report that deteriorations of postural stability coincides with the onset cybersickness. It is unclear whether these deteriorations are the cause or a consequence of cybersickness. Thus, it is also unclear whether measures of postural stability may either predict susceptibility (cause) or objectively measure (consequence) the malaise. To examine whether deteriorations of postural stability can either predict or objectively measure cybersickness, healthy active adults (n = 50) were exposed to one of two different 10 min 360˚ VR videos. Postural stability was assessed, using a force platform, before exposure with eyes open (baseline) and eyes closed, during the first and last minute of exposure, and approximately 10 min after exposure. The deterioration of postural stability from baseline to the first minute of exposure was larger in participants who reported cybersickness, compared to those who did not, for both total trace length (p = 0.017) and standard deviation velocity (p = 0.008). However, there was substantial individual variation and overlap between sick and well participants. Deteriorations of postural stability from baseline to the eyes closed condition did not differ between sick and well participants (trace length, p = 0.270; standard deviation velocity, p = 0.112). There was a significant correlation between the severity of cybersickness and the change of postural stability from the first to the last minute of VR exposure for trace length (r_s=0.32, p = 0.027), but not standard deviation velocity (r_s=0.20, p = 0.187). The deteriorations had returned to baseline levels 10 min after exposure. These findings suggest that deteriorations of postural stability was both a predictor and objective measure at a group level. However, the large individual variation, substantial overlap between sick and well participants, and the limited strength of correlations suggest that deterioration of postural stability has limited practical value as both a predictor and objective measure. These findings emphasize the complicated nature of the relationship between cybersickness and postural stability.

Psychometric evaluation of Simulator Sickness Questionnaire and its variants as a measure of cybersickness in consumer virtual environments

Cybersickness, i.e. visually induced motion sickness, remains as a negative effect that is detrimental to the user experience of VEs (virtual environments) developed for VR (virtual reality) consumers. As the VR technology evolves, it is rather triggered by application aspects rather than hardware limitations. For this reason, there is still a need for a measurement method to assess and compare VEs for cybersickness effects. SSQ (Simulation Sickness Questionnaire) is used for measuring users' level of sickness symptoms and is highly appreciated in VR research. However, it is criticized for its psychometric qualities and applicability in VR, as a measure of cybersickness. Recently, two variants of SSQ were offered for measuring cybersickness, CSQ (Cybersickness Questionnaire) and VRSQ (Virtual Reality Sickness Questionnaire). There is also another variant with a different factor structure, which we call FSSQ, that is based on French translation of SSQ. Our study compares SSQ and these variants for their psychometric qualities; construct validity, discriminant validity, internal reliability, test-retest reliability and sensitivity to distinguish application aspects of VEs that are related to cybersickness. Using a within-subjects experiment design, we evaluated 7 different VEs with 32 participants through 9 sessions, resulting with 288 responses to the 16-item SSQ. Results suggested that both VRSQ and CSQ were valid and reliable measures of cybersickness, as well as being sensitive to application aspects such as translational and rotational movements required by users for navigation in VEs. Compared to SSQ and FSSQ; the cybersickness questionnaires, CSQ and VRSQ, revealed better indicators of validity. On the other hand, we assume that the development of the two cybersickness scales had limitations in sample size to represent VR consumers and limitations in stimuli to represent the applications aspects of consumer VEs. We suggest further evaluation of cybersickness symptoms with larger samples and broader range of applications to identify the symptoms and the construct of a subjective measurement tool.

Motion sickness-susceptible participants exposed to coherent rotating dot patterns show excessive N2 amplitudes and impaired theta-band phase synchronization

Visually induced motion sickness (VIMS) can occur via prolonged exposure to visual stimulation that generates the illusion of self-motion (vection). Not everyone is susceptible to VIMS and the neural mechanism underlying susceptibility is unclear. This study explored the differences of electroencephalographic (EEG) signatures between VIMS-susceptible and VIMS-resistant groups. Thirty-two-channel EEG data were recorded from 12 VIMS-susceptible and 15 VIMS-resistant university students while they were watching two patterns of moving dots: (1) a coherent rotation pattern (vection-inducing and potentially VIMS-provoking pattern), and (2) a random movement pattern (non-VIMS-provoking control). The VIMS-susceptible group exhibited a significantly larger increase in the parietal N2 response when exposed to the coherent rotating pattern than when exposed to control patterns. In members of the VIMS-resistant group, before vection onset, global connectivity from all other EEG electrodes to the right-temporal-parietal and to the right-central areas increased, whereas after vection onset the global connectivity to the right-frontal area reduced. Such changes were not observed in the susceptible group. Further, the increases in N2 amplitude and the identified phase synchronization index were significantly correlated with individual motion sickness susceptibility. Results suggest that VIMS susceptibility is associated with systematic impairment of dynamic cortical coordination as captured by the phase synchronization of cortical activities. Analyses of dynamic EEG signatures could be a means to unlock the neural mechanism of VIMS.

More vection means more velocity storage activity: a factor in visually induced motion sickness?

Full-field visual rotation around the vertical axis induces a sense of self-motion (vection), optokinetic nystagmus (OKN), and, eventually, also motion sickness (MS). If the lights are then suddenly switched off, optokinetic afternystagmus (OKAN) occurs. This is due to the discharge of the velocity storage mechanism (VSM), a central integrative network that has been suggested to be involved in motion sickness. We previously showed that visually induced motion sickness (VIMS) following optokinetic stimulation is dependent on vection intensity. To shed light on this relationship, the current study investigated whether vection intensity is related to VSM activity, and thus, to the OKAN. In repetitive trials (eight per condition), 15 stationary participants were exposed to 120 s of visual yaw rotation (60°/s), followed by 90 s in darkness. The visual stimulus either induced strong vection (i.e., scene rotating normally) or weak vection (central and peripheral part moving in opposite directions). Eye movements and subjective vection intensity were continuously measured. Results showed that OKAN occurred less frequently and with lower initial magnitude in the weak-vection condition compared to the strong-vection condition. OKAN decay time constants were not significantly different. The results suggest that the stimuli that produced strong vection also enhanced the charging of the VSM. As VSM activity presumably is a factor in motion sickness, the enhanced VSM activity in our strong-vection condition hints at an involvement of the VSM in VIMS, and could explain why visual stimuli producing a strong sense of vection also elicit high levels of VIMS.

Allocating less attention to central vision during vection is correlated with less motion sickness

Visually induced motion sickness (VIMS) is a common discomfort response associated with vection-provoking stimuli. It has been suggested that susceptibility to VIMS depends on the ability to regulate visual performance during vection. To test this, 29 participants, with VIMS susceptibility assessed by Motion Sickness Susceptibility Questionnaire, were recruited to undergo three series of sustained attention to response tests (SARTs) while watching dot pattern stimuli known to provoke roll-vection. In general, SARTs performance was impaired in the central visual field (CVF), but improved in peripheral visual field (PVF), suggesting the reallocation of attention during vection. Moreover, VIMS susceptibility was negatively correlated with the effect sizes, suggesting that participants who were less susceptible to VIMS showed better performance in attention re-allocation. Finally, when trained to re-allocation attention from the CVF to the PVF, participants experienced more stable vection. Findings provide a better understanding of VIMS and shed light on possible preventive measures. Practitioner Summary: Allocating less visual attention to central visual field during visual motion stimulation is associated with stronger vection and higher resistance to motion sickness. Virtual reality application designers may utilise the location of visual tasks to strengthen and stabilise vection, while reducing the potential of visually induced motion sickness.

Framing visual roll-motion affects postural sway and the subjective visual vertical

Effects of visual roll-motion on postural sway and the subjective visual vertical (SVV) often is studied using mechanical devices, whereas electronic displays offer cheaper and more flexible alternatives. These devices typically emit and reflect light scattered by the edges of the screen, providing Earth-fixed cues of verticality. These cues may decrease the effects of rotating stimuli, a possibility that has not been studied explicitly before in one experimental design. We exposed 16 participants to a visual dot pattern, either stationary, or rotating in roll, that was or was not surrounded by a visible Earth-fixed reference frame. To eliminate unintended visual cues, the experiment was performed in complete darkness and participants wore neutral density goggles passing only 1% of light. Postural sway was measured using a force platform. SVV measurements were obtained from a visible rod. To monitor the participants, motion sickness severity was obtained with an 11-point rating scale. Results showed that the presence of an Earth-fixed frame significantly decreased the effect of the rotating pattern on postural sway and SVV deviations. Therefore, when studying subjective verticality related effects of visual stimuli, it is imperative that all visual Earth-fixed cues are not just minimized but completely eliminated. The observation that an Earth-fixed frame significantly decreased the effect of the rotating pattern on both postural sway and the SVV points towards a common neural origin, possibly involving a neural representation of verticality. Finally, we showed that an electronic screen can yield similar effect sizes as those taken from the literature using mechanical devices.

Correlations between individual susceptibility to visually induced motion sickness and decaying time constant of after-nystagmus

This study examines the correlations between optokinetic after-nystagmus (OKAN) parameters and individual susceptibility to visually induced motion sickness (VIMS). Twenty-seven participants were exposed to vertical black-and-white stripes drifting along the yaw axis at 60° per second for 30 min to collect individual VIMS data (Phase 1). Two weeks after the exposure, OKANs were measured (Phase 2). 19 out of 27 participants (i.e., 70%) exhibited consistent OKAN patterns. Significant correlations between the time constants of OKAN and levels of VIMS experienced by the same viewers were found. Four months later, these 27 participants were invited back for a second OKAN measurement (Phase 3). Twenty-one participants came back. Their two OKAN measurements were significantly correlated (r = 0.69, p = 0.001). Rated levels of VIMS in phase 1 significantly correlated with the time constant of OKAN in both Phase 2 (r = 0.51, p = 0.044) and Phase 3 (r = 0.74, p = 0.006). The implications of the correlation results are discussed.

Cybersickness without the wobble: Experimental results speak against postural instability theory

It has been suggested that postural instability is necessary for cybersickness to occur. Seated and standing subjects used a head-mounted display to view a virtual tunnel that rotated about their line of sight. We found that the offset direction of perceived vertical settings matched the direction of the tunnel's rotation, so replicating earlier findings. Increasing rotation speed caused cybersickness to increase, but had no significant impact on perceived vertical settings. Postural sway during rotation was similar to postural sway during rest. While a minority of subjects exhibited postural sway in response to the onset of tunnel rotation, the majority did not. Furthermore, cybersickness increased with rotation speed similarly for the seated and standing conditions. Finally, subjects with greater levels of cybersickness exhibited less variation in postural sway. These results lead us to conclude that the link between postural instability and cybersickness is a weak one in the present experiment.

Visually induced motion sickness when viewing visual oscillations of different frequencies along the fore-and-aft axis: keeping velocity versus amplitude constant

Exposure to visual oscillations (VOs) can lead to visually induced motion sickness (VIMS). The level of VIMS among viewers has been shown to vary when the frequency of the VOs is changed either by manipulating their amplitude or velocity. The present study investigates whether the level of VIMS would change if we keep the root mean square (rms) velocity or amplitude of VOs constant while manipulating the VO frequency. A total of 25 individuals were exposed to random-dot and checkerboard VOs along the fore-and-aft axis in two experiments. Changing the amplitude (or frequency) of VOs while keeping the rms velocity constant did not affect the level of VIMS; however, increasing the rms velocity (or frequency) of VOs while keeping the amplitude constant made VIMS significantly worse. Practitioner Summary: Exposure to VOs of the same frequency can cause different levels of nausea depending on the combination of oscillation amplitude and velocity. Results suggest an opportunity for game designers to reduce symptoms of game sickness by using the correct combinations of velocity and amplitude of the visual motions.

Pleasant music as a countermeasure against visually induced motion sickness

Visually induced motion sickness (VIMS) is a well-known side-effect in virtual environments or simulators. However, effective behavioral countermeasures against VIMS are still sparse. In this study, we tested whether music can reduce the severity of VIMS. Ninety-three volunteers were immersed in an approximately 14-minute-long video taken during a bicycle ride. Participants were randomly assigned to one of four experimental groups, either including relaxing music, neutral music, stressful music, or no music. Sickness scores were collected using the Fast Motion Sickness Scale and the Simulator Sickness Questionnaire. Results showed an overall trend for relaxing music to reduce the severity of VIMS. When factoring in the subjective pleasantness of the music, a significant reduction of VIMS occurred only when the presented music was perceived as pleasant, regardless of the music type. In addition, we found a gender effect with women reporting more sickness than men. We assume that the presentation of pleasant music can be an effective, low-cost, and easy-to-administer method to reduce VIMS.