Effect of Progressive Gaze Stability Exercises on Holistic Aspects of Chronic Motion Sensitivity

Background: Motion sensitivity, also referred to as motion sickness, is a common condition among general population. It is a complex syndrome and is associated with presence of nausea and vomiting headache, drowsiness, cold sweating, pallor of varying degrees, increased salivation. Postural instability and anxiety are also identified to be associated with motion sensitivity. There is a close relationship between the vestibular system and motion sensitivity and vestibular system. The aim of this study was to investigate the effect of progressive gaze stability exercises on holistic aspects of chronic motion sensitivity. Methods: A single blind randomized controlled trial was conducted where participants were blinded to type of intervention. Forty one healthy young adults of both genders within the age group of 20 to 40 years with chronic motion sensitivity were recruited in the study. Baseline and post intervention assessment of postural stability, motion sensitivity, and anxiety was measured for each participant using, Bertec Balance Advantage-Dynamic Computerized Dynamic Posturography with Immersion Virtual Reality (CDP-IVR), Motion Sensitivity Quotient (MSQ), Motion Sensitivity Susceptibility Questionnaire Short Form (MSSQ-Short), and State-Trait Anxiety Inventory for Adults (STAI Form Y-2). Results: There was a significant difference for condition 2 (p=0.05), but not for condition 1 (p=0.44) for the mean CDP-IVR average score post intervention between the intervention and sham groups. For condition 2, the intervention group had 117% increase in CDP-IVR average score compared to 35.2% increase in the sham group. Also, there was a significant difference in mean MSQ between the two groups (p=0.045). There was a significant inverse correlation between MSQ and CDP-IVR average equilibrium % of Condition 1 (ρ = -0.44, p = 0.004). Conclusions: Progressive gaze stability exercises reduced motion sensitivity and improved postural stability in participants with chronic motion sensitivity. Also, perception of motion sensitivity was observed to be inversely correlated with postural stability. There was no impact of gaze stability exercises observed on subjective perception of anxiety among this population. Also, HEP adherence strategies were beneficial to ensure exercise adherence in participants with chronic motion sensitivity

I Am The Passenger: How Visual Motion Cues Can Influence Sickness For In-Car VR

This paper explores the use of VR Head Mounted Displays (HMDs) in-car and in-motion for the first time. Immersive HMDs are becoming everyday consumer items and, as they offer new possibilities for entertainment and productivity, people will want to use them during travel in, for example, autonomous cars. However, their use is confounded by motion sickness caused in-part by the restricted visual perception of motion conflicting with physically perceived vehicle motion (accelerations/rotations detected by the vestibular system). Whilst VR HMDs restrict visual perception of motion, they could also render it virtually, potentially alleviating sensory conflict. To study this problem, we conducted the first on-road and in motion study to systematically investigate the effects of various visual presentations of the real-world motion of a car on the sickness and immersion of VR HMD wearing passengers. We established new baselines for VR in-car motion sickness, and found that there is no one best presentation with respect to balancing sickness and immersion. Instead, user preferences suggest different solutions are required for differently susceptible users to provide usable VR in-car. This work provides formative insights for VR designers and an entry point for further research into enabling use of VR HMDs, and the rich experiences they offer, when travelling

Frequency characteristics of visually induced motion sickness

Objective: The aim of this study was to explore the frequency response of visually induced motion sickness (VIMS) for oscillating linear motion in the foreand- aft axis. Background: Simulators, virtual environments, and commercially available video games that create an illusion of self-motion are often reported to induce the symptoms seen in response to true motion. Often this human response can be the limiting factor in the acceptability and usability of such systems. Whereas motion sickness in physically moving environments is known to peak at an oscillation frequency around 0.2 Hz, it has recently been suggested that VIMS peaks at around 0.06 Hz following the proposal that the summed response of the visual and vestibular selfmotion systems is maximized at this frequency. Methods: We exposed 24 participants to random dot optical flow patterns simulating oscillating foreand- aft motion within the frequency range of 0.025 to 1.6 Hz. Before and after each 20-min exposure, VIMS was assessed with the Simulator Sickness Questionnaire. Also, a standard motion sickness scale was used to rate symptoms at 1-min intervals during each trial. Results: VIMS peaked between 0.2 and 0.4 Hz with a reducing effect at lower and higher frequencies. Conclusion: The numerical prediction of the “crossover frequency” hypothesis, and the design guidance curve previously proposed, cannot be accepted when the symptoms are purely visually induced. Application: In conditions in which stationary observers are exposed to optical flow that simulates oscillating fore-and-aft motion, frequencies around 0.2 to 0.4 Hz should be avoided

Frequency Characteristics of Visually Induced Motion Sickness

This article was published in the journal, Human Factors [Sage Publications / © Human Factors and Ergonomics Society.]. The definitive version is available at: http://dx.doi.org/10.1177/0018720812469046Objective: The aim of this study was to explore the frequency response of visually induced motion sickness (VIMS) for oscillating linear motion in the foreand- aft axis. Background: Simulators, virtual environments, and commercially available video games that create an illusion of self-motion are often reported to induce the symptoms seen in response to true motion. Often this human response can be the limiting factor in the acceptability and usability of such systems. Whereas motion sickness in physically moving environments is known to peak at an oscillation frequency around 0.2 Hz, it has recently been suggested that VIMS peaks at around 0.06 Hz following the proposal that the summed response of the visual and vestibular selfmotion systems is maximized at this frequency. Methods: We exposed 24 participants to random dot optical flow patterns simulating oscillating foreand- aft motion within the frequency range of 0.025 to 1.6 Hz. Before and after each 20-min exposure, VIMS was assessed with the Simulator Sickness Questionnaire. Also, a standard motion sickness scale was used to rate symptoms at 1-min intervals during each trial. Results: VIMS peaked between 0.2 and 0.4 Hz with a reducing effect at lower and higher frequencies. Conclusion: The numerical prediction of the “crossover frequency” hypothesis, and the design guidance curve previously proposed, cannot be accepted when the symptoms are purely visually induced. Application: In conditions in which stationary observers are exposed to optical flow that simulates oscillating fore-and-aft motion, frequencies around 0.2 to 0.4 Hz should be avoided

New VR Navigation Techniques to Reduce Cybersickness

In nowadays state of the art VR environments, displayed in CAVEs or HMDs, navigation technics may frequently induce cybersickness or VR-Induced Symptoms and Effects (VRISE), drastically limiting the friendly use of VR environments with no navigation limitations. In two distinct experiments, we investigated acceleration VRISE thresholds for longitudinal and rotational motions and compared 3 different VR systems: 2 CAVEs and a HMD (Oculus Rift DK2). We found that VRISE occur more often and more strongly in case of rotational motions and found no major difference between the CAVEs and the HMD. Based on the obtained thresholds we developed a new "Head Lock" navigation method for rotational motions in a virtual environment in order to generate a “Pseudo AR” mode, keeping fixed visual outside world references. Thanks to a third experiment we have shown that this new metaphor significantly reduces VRISE occurrences and may be a useful base for future natural navigation technics

How to avoid simulation sickness in virtual environments during user displacement

Driving simulation (DS) and Virtual Reality (VR) share the same technologies for visualization and 3D vision and may use the same technics for head movement tracking. They experience also similar difficulties when rendering the displacements of the observer in virtual environments, especially when these displacements are carried out using driver commands, including steering wheels, joysticks and nomad devices. High values for transport delay, the time lag between the action and the corresponding rendering cues and/or visual-vestibular conflict, due to the discrepancies perceived by the human visual and vestibular systems when driving or displacing using a control device, induces the socalled simulation sickness. While the visual transport delay can be efficiently reduced using high frequency frame rate, the visual-vestibular conflict is inherent to VR, when not using motion platforms. In order to study the impact of displacements on simulation sickness, we have tested various driving scenarios in Renault’s 5-sided ultra-high resolution CAVE. First results indicate that low speed displacements with longitudinal and lateral accelerations under a given perception thresholds are well accepted by a large number of users and relatively high values are only accepted by experienced users and induce VR induced symptoms and effects (VRISE) for novice users, with a worst case scenario corresponding to rotational displacements. These results will be used for optimization technics at Arts et Métiers ParisTech for motion sickness reduction in virtual environments for industrial, research, educational or gaming applications

Rod and frame alignment times increase when the frame is tilted.

The Rod and Frame test measures an individual’s subjective assessment of visual vertical and horizontal in the presence of a surrounding tilted frame. Attention has focused upon the effects of the surrounding frame upon spatial accuracy (Spatial Frame Effect). We have investigated if the tilted frame also affects the time that subjects take to make the alignment (Temporal Frame Effect). Results: 125 subjects performed a computerised Rod and Frame test to investigate the effects of a tilted frame on subjective visual vertical and horizontal. In addition the program recorded the time taken to make each alignment. For most subjects the mean Spatial Frame Effect was small (vertical 1.62, SD 0.93; horizontal 1.9, SD 1.43). The mean time taken to make alignments in the presence of a tilted frame was longer than when the frame was not tilted (vertical, +3.4s, SD 4.4; horizontal, +3.2s, SD 4.5). Differences in the times taken when the rod and frame were presented congruently and incongruently could be fully accounted for by the differences in steps needed to move the rod to its final alignment. No relationship was found between the spatial accuracy and the time to make the alignment and there was no relationship between the Spatial and Temporal Frame Effects. Conclusions: This study suggests that the Spatial, and Temporal, Frame Effects provide information about different aspects of the process of resolving conflicting visual information when making judgments on alignment. In everyday functions such as the maintenance of balance or susceptibility to motion sickness, the increased time taken may be as important as spatial accuracy

Exploring Wearable Technologies for Health Monitoring: Applications in Motion Sickness and Dehydration

Wearable devices have enhanced health monitoring in clinical settings by effectively measuring physiological signals to inform prevention strategies. With the rapid development of sensors and data-driven decision-making, wearables can be applied in non-clinical settings to monitor various health conditions. Oftentimes, the most direct, accurate measurements are inaccessible or impractical during real-life, unscripted daily activities (e.g., equipment access). In this dissertation, signal-based models were developed to evaluate common wearables for health monitoring, with specific applications on motion sickness and dehydration. Motion sickness can range from stomach discomfort to severe nausea and affects passengers more frequently than drivers. As automated vehicles and mobility solutions become normalized, motion sickness incidence is anticipated to increase among on-road passengers. As such, there is a greater need for early detection of vehicular motion sickness. Previous studies have shown postural instability to be associated with motion sickness. Therefore, assessments of standing balance may be useful for estimating levels of motion sickness. However, there are limited studies of post-drive standing balance that have been conducted in passenger vehicles or under ecologically-relevant conditions. In this dissertation, three studies quantified motion sickness and standing balance of vehicle passengers following continuous driving exposures deployed on a closed test track and on-road environments using a wearable inertial measurement unit. In the closed test track study, trunk postural sway increased significantly during the more challenging balance exercises. Post-drive changes to postural sway metrics (e.g., sway velocity and path length) were larger for drives during which participants performed a visual-based task on a handheld tablet-based device, as compared to drives without a task. In the on-road study, changes in post-drive postural sway were consistent with the findings from the closed test track study. However, there was no meaningful effect of performing a task on changes in postural sway metrics. In the third study, significant changes in post-drive postural sway were associated with the severest motion sickness responses, suggesting that sway metrics could characterize motion sickness. While preliminary, these findings could inform monitoring approaches of vehicular motion sickness using postural sway data from wearable sensors. Additional work would further explore wearables as a potential screening tool for motion sickness susceptibility prior to the drive. In the fourth study of this dissertation, wearables were used to develop a noninvasive method for continuously measuring dehydration; untreated, dehydration can lead to performance detriments and in severe cases, death due to heat-related complications. Participants performed a series of orthostatic postural movements before and after a cycling session while donning common wearable that measured heart rate and trunk kinematic data. A machine learning model was trained and accurately classified a level of fluid loss equivalent to 2% of bodyweight. Using data from wearable devices, this method can support preemptive fluid replenishment and subsequently minimize potential decreases in performance; reduce the risk of serious heat injuries; and inform users to take additional hydration assessments. These findings demonstrated the feasibility of wearable technologies for monitoring health conditions that are difficult to assess in non-clinical settings. Specifically, this dissertation developed models that could relate motion sickness and post-drive postural sway measured from wearable devices, and could reliably leverage common sensor-based signals to minimize dehydration. Future applications with wearable devices could especially support secondary prevention strategies, which are approaches aimed at minimizing the impacts of health conditions once they have occurred.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169663/1/victle_1.pd

Modeling of occupant's head movement behavior in motion sickness study via time delay neural network

Passengers are more susceptible to experiencing motion sickness (MS) than drivers. The difference in the severity of MS is due to their different head movement behavior during curve driving. When negotiating a curve, the passengers tilt their heads towards the lateral acceleration direction while the drivers tilt their heads against it. Thus, to reduce the passengers’ level of MS, they need to reduce their head’s tilting angle towards the lateral acceleration direction. Designing MS minimization strategies is easier if the correlation between the head movement and lateral acceleration is known mathematically. Therefore, this paper proposes the utilization of a time delay neural network (TDNN) to model the correlation of the occupant’s head movement and lateral acceleration. An experiment was conducted to gather real-time data for the modeling process. The results show that TDNN manages to model the correlation by producing a similar output response to the actual response. Thus, it is expected that the correlation model could be used as an occupant’s head movement predictor tool in future studies of MS