[Visual prevention from motion sickness in cars]

Combining visual cues with relaxing music, perfume and ventilation to reduce passenger car sickness: An experimental study

The autonomous, digital, and electric transformation of passenger vehicles is projected to elevate the incidence of motion sickness among occupants. This study investigates the effectiveness of an "anti-motion sickness" system that features dynamic light stimuli to support visual perception of longitudinal motion, combined with relaxing music, perfume and ventilation pulses to enhance user wellbeing. In an experimental design aimed at replicating a realistic passenger drive, fifty-three subjects were tested as front passengers engaged in a gaming activity. Subjective motion sickness ratings were collected throughout the drive, and the development of symptoms was monitored through in-ear physiological measurements, including RR-intervals, core temperature, and oxygen saturation. Post hoc analyses indicated non-significant improvement in subjective assessments of motion sickness. Similarly, physiological measurements did not demonstrate any significant difference across conditions. The tested system was however more effective in mitigating car sickness for low susceptible than for mid-to-high susceptible individuals.

Motion sickness and visual impairment

Motion sickness (MS) is caused by exposure to unfamiliar movements. The theory is that MS is due to a conflict between information perceived by the vestibular, visual, and somatosensory systems. This study examines the role of vision in MS by comparing MS susceptibility among individuals with varying degrees of visual impairments to sighted individuals. We hypothesized that subjects with no perception of light would be less susceptible to MS than less impaired subjects, who would themselves be less susceptible than sighted subjects. To address these, the Motion Sickness Susceptibility Questionnaire (MSSQ1) was administered to 340 subjects (170 visually impaired paired with 170 sighted subjects) to assess their susceptibility to various modes of transport under real conditions. Visually impaired subjects were divided into subgroups according to the presence (partially sighted) or absence (totally blind) of light perception, as well as the period of onset of impairment (congenital or acquired). Totally blind individuals are significantly less susceptible to MS than partially sighted (p = 0.001), and sighted (p < 0.001) subjects, with no difference between partially sighted and sighted subjects (p = 0.526). Additionally, acquired totally blind subjects are less susceptible to MS than congenitally blind subjects (p = 0.038). Thus, despite a lower susceptibility totally blind subjects may still be susceptible to MS. The absence of vision reduces MS susceptibility but does not completely prevent it. This suggests that vision is more a mediator, than an essential condition for MS appearance.

On the road to comfort: Evaluating the influence of motion predictability on motion sickness in automated vehicles

Automated vehicles could increase the risk of motion sickness because occupants are not involved in driving and do not watch the road. This paper aimed to investigate the influence of motion predictability on motion sickness in automated vehicles, as better motion anticipation is believed to mitigate motion sickness. In a simulator-based study, twenty participants experienced two driving conditions differing only in turn directions. The repetitive condition featured a repeating turn direction pattern. The non-repetitive condition contained pseudo-randomly ordered turn directions. To mimic an 'eyes-off-the-road' setting and prevent visual motion anticipation, road visuals were omitted. No significant differences in sickness or head motion, a metric for motion anticipation, were found between the conditions. No participant recognised the repeating turn pattern. This suggests no increased motion anticipation in the repetitive condition, possibly due to a reduced ability to recognise a repeating motion pattern in one degree of freedom within more complex motion.

Will visual cues help alleviating motion sickness in automated cars? A review article

This paper examines the feasibility of incorporating visual cueing systems within vehicles to mitigate the risk of experiencing motion sickness. The objective is to enhance passenger awareness and the ability to anticipate the forces associated with car travel motion. Through a comprehensive literature review, the findings demonstrate that visual cues can mitigate motion sickness for particular in-vehicle configurations, whereas their influence on situational awareness is not clear yet. Each type of visual cue proved more effective when presented in the peripheral field of view rather than solely in the central vision. Promising applications can be found within interactive screens and ambient lighting, while the use of extended reality shows potential for future investigations. In addition, integrating such systems into highly automated vehicles shows potential to improve their overall user acceptance.

Electrogastrography in Autonomous Vehicles-An Objective Method for Assessment of Motion Sickness in Simulated Driving Environments

Autonomous vehicles are expected to take complete control of the driving process, enabling the former drivers to act as passengers only. This could lead to increased sickness as they can be engaged in tasks other than driving. Adopting different sickness mitigation techniques gives us unique types of motion sickness in autonomous vehicles to be studied. In this paper, we report on a study where we explored the possibilities of assessing motion sickness with electrogastrography (EGG), a non-invasive method used to measure the myoelectric activity of the stomach, and its potential usage in autonomous vehicles (AVs). The study was conducted in a high-fidelity driving simulator with a virtual reality (VR) headset. There separate EGG measurements were performed: before, during and after the driving AV simulation video in VR. During the driving, the participants encountered two driving environments: a straight and less dynamic highway road and a highly dynamic and curvy countryside road. The EGG signal was recorded with a proprietary 3-channel recording device and Ag/AgCl cutaneous electrodes. In addition, participants were asked to signalize whenever they felt uncomfortable and nauseated by pressing a special button. After the drive they completed also the Simulator Sickness Questionnaire (SSQ) and reported on their overall subjective perception of sickness symptoms. The EGG results showed a significant increase of the dominant frequency (DF) and the percentage of the high power spectrum density (FSD) as well as a significant decrease of the power spectrum density Crest factor (CF) during the AV simulation. The vast majority of participants reported nausea during more dynamic conditions, accompanied by an increase in the amplitude and the RMS value of EGG. Reported nausea occurred simultaneously with the increase in EGG amplitude. Based on the results, we conclude that EGG could be used for assessment of motion sickness in autonomous vehicles. DF, CF and FSD can be used as overall sickness indicators, while the relative increase in amplitude of EGG signal and duration of that increase can be used as short-term sickness indicators where the driving environment may affect the driver.

Maneuver-Based Objectification of User Comfort Affecting Aspects of Driving Style of Autonomous Vehicle Concepts

Driving maneuvers try to objectify user needs regarding the driving dynamics for a vehicle concept. As autonomous vehicles will not be driven by people, the driving style that merges the individual aspects of driving dynamics, like user comfort, will be part of the vehicle concept itself. New driving maneuvers are, therefore, necessary to objectify the driving style of autonomous vehicle concepts with all its interdependencies relating to the individual aspects. This paper presents a methodology to design such driving maneuvers and includes a pilot study and a user study. As an example, the methodology was applied to the parameters of user comfort and travel time. The driven maneuvers resulted in statistical equations to objectify the interdependencies of these two aspects. Finally, this paper provides an outlook for needed maneuvers in order to tackle the entire driving style with its multidimensional facets.

Knowing what's coming: Anticipatory audio cues can mitigate motion sickness

Being able to anticipate upcoming motion is known to potentially mitigate sickness resulting from provocative motion. We investigated whether auditory cues could increase anticipation and subsequently reduce motion sickness. Participants (N = 20) were exposed on a sled on a rail track to two 15-min conditions. Both were identical in terms of motion, being composed of the same repeated 9 m fore-aft displacements, with a semi-random timing of pauses and direction. The auditory cues were either 1) informative on the timing and direction of the upcoming motion, or 2) non-informative. Illness ratings were recorded at 1-min intervals using a 11-point scale. After exposure, average illness ratings were significantly lower for the condition that contained informative auditory cues, as compared to the condition without informative cues. This knowledge, i.e. that auditory signals can improve anticipation to motion, could be of importance in reducing carsickness in domains such as that of autonomous vehicles.

Moving base driving simulators' potential for carsickness research

We investigated whether motion sickness analogous to carsickness can be studied in a moving base simulator, despite the limited motion envelope. Importantly, to avoid simulator sickness, vision outside the simulator cabin was restricted. Participants (N = 16) were exposed blindfolded to 15-min lateral sinusoidal motion at 0.2 Hz and 0.35 Hz on separate days. These conditions were selected to realize optimal provocativeness of the stimulus given the simulator's maximum displacement and knowledge on frequency-acceleration interactions for motion sickness. Average motion sickness on an 11-point scale was 2.21 ± 1.97 for 0.2 Hz and 1.93 ± 1.94 for 0.35 Hz. The motion sickness increase over time was comparable to that found in studies using actual vehicles. We argue that motion base simulators can be used to incite motion sickness analogous to carsickness, provided considerable restrictions on vision. Future research on carsickness, potentially more prevalent in autonomous vehicles, could benefit from employing simulators.

Looking forward: In-vehicle auxiliary display positioning affects carsickness

Carsickness is associated with a mismatch between actual and anticipated sensory signals. Occupants of automated vehicles, especially when using a display, are at higher risk of becoming carsick than drivers of conventional vehicles. This study aimed to evaluate the impact of positioning of in-vehicle displays, and subsequent available peripheral vision, on carsickness of passengers. We hypothesized that increased peripheral vision during display use would reduce carsickness. Seated in the front passenger seat 18 participants were driven a 15-min long slalom on two occasions while performing a continuous visual search-task. The display was positioned either at 1) eye-height in front of the windscreen, allowing peripheral view on the outside world, and 2) the height of the glove compartment, allowing only limited view on the outside world. Motion sickness was reported at 1-min intervals. Using a display at windscreen height resulted in less carsickness compared to a display at glove compartment height.

Vertical heterophoria and susceptibility to visually induced motion sickness

Motion sickness is reported to be a common symptom in patients with vertical heterophoria. The goal of this study was to assess the relationship between vertical phoria and susceptibility to motion sickness in a nonclinical sample of 43 subjects. Vertical phoria was measured with a Maddox rod after 30 s of occlusion. To evaluate susceptibility to motion sickness, subjects read text while sitting inside a rotating optokinetic drum for 10 min. Subjects rated their level of motion sickness at 1 min intervals during drum rotation and the magnitude of 13 motion sickness symptoms after drum rotation ended. The magnitude of vertical phoria ranged from 0 to 2.13 prism diopters (pd) with a mean of 0.46 pd and correlated significantly with both the maximum rating of motion sickness during drum rotation and the summed symptom score following rotation. A vertical phoria of 0.75 pd discriminated best between subjects with low vs high summed motion sickness symptom scores (p < 0.0001). Introducing a prism to artificially increase the phoria of 12 subjects with vertical phorias <0.75 pd increased motion sickness symptoms in only 1 subject. Prisms that reduced the phoria of subjects with vertical phorias > 0.75 pd reduced motion sickness symptoms in 2 of the 4 subjects tested. The results confirm an association between vertical phoria and motion sickness, but suggest the relationship may not be causal.

Chosen postures during specific sitting activities

This research study analysed the interaction between people's postures and activities while in semi-public/leisure situations and during transportation (journey by train). In addition, the use of small electronic devices received particular emphasis. Video recordings in German trains and photographs in Dutch semi-public spaces were analysed using a variation of Branton and Grayson's (An evaluation of train seats by observation of sitting behaviour. Ergonomics, 10 (1), (1967), 35-51) postural targeting forms and photos. The analysis suggests a significant relationship between most activities and the position of the head, trunk and arms during transportation situations. The relationship during public situations is less straightforward. Watching, talking/discussing and reading were the most observed activities for the transportation and leisure situations combined. Surprisingly, differences in head, trunk, arm and leg postures were not significant when using small electronic devices. Important issues not considered in this study include the duration of the activities, the gender and age of observed subjects and the influence of the time of day. These are interesting issues to consider and include for future research. STATEMENT OF RELEVANCE: This study shows what activities people choose to carry out and their related postures when not forced to a specific task (e.g. driving). The results of this study can be used for designing comfortable seating in the transportation industry (car passenger, train, bus and aircraft seats) and semi-public/leisure spaces.

Susceptibility to seasickness

This paper explains part of the observed variability in passenger illness ratings aboard ships by gender, age and sickness history. Within the framework of a European project, 2840 questionnaires, gathered on several ships operating all over Europe, were analysed. Gender, age and sickness history all had a highly significant effect on seasickness. Furthermore, these effects could be characterized by two fixed parameters describing a general age effect, a third parameter dependent on sickness history and a fourth parameter dependent on gender. Female illness ratings peaked at an age of 11 years, 1.5 times as high as male ratings, which peaked at an age of 21 years. At higher ages, illness ratings decrease to only 20% of their maximum, reducing gender differences to zero. Passengers with a previous history of seasickness rated their illness about two times higher than those who had not felt sick before.

Motion sickness in public road transport: the effect of driver, route and vehicle

Relationships between vehicle motion and passenger sickness have been investigated in a survey of 3256 passengers travelling on 56 mainland UK bus or coach journeys. Vehicle motion was measured throughout all journeys, yielding over 110 h of six-axis coach motion data from five types of coach and 17 different drivers. Overall, 28.4% of passengers reported feelings of illness, 12.8% reported nausea and 1.7% reported vomiting during coach travel. Passenger nausea and illness ratings increased with increased exposure to lateral coach motion at low frequencies (< 0.5 Hz). Motion in other axes correlated less well with sickness, although there were some intercorrelations between the motions in the different axes. Sickness levels among passengers were greater with drivers who drove to produce higher average magnitudes of fore-and-aft and lateral vehicle motion. Nausea occurrence was greater on routes classified as being predominantly cross-country where magnitudes of lateral vehicle motion were significantly higher. Lateral motion and motion sickness increased from the front to the rear of each vehicle. No significant differences in sickness were found between the five different vehicle types used in the study. The applicability of a motion sickness dose model to these data is discussed.

Motion sickness in public road transport: passenger behavior and susceptibility

The aim of this research was to identify personal and environmental factors influencing individual susceptibility to motion sickness during road transport. A questionnaire survey of 3256 coach travellers was conducted. Information on passenger characteristics, travel regularity, activity during travel, use of anti-motion sickness drugs and self-reported motion sickness susceptibility were collected over 56 private hire coach journeys. Details of the travel environment (visibility, temperature and seating) were also recorded. The relationship of these variables with passenger illness and more specific symptoms of motion sickness are examined. Overall, 28.4% of passengers reported feeling ill, 12.8% reported nausea and 1.7% reported vomiting during coach travel. Travel sickness decreased with increasing passenger age and greater travel experience. Females were more likely to report feeling ill during coach travel than males by a ratio of four to three. Poor forward visibility was found to increase sickness. Passenger illness occurrence was approximately three times higher for passengers with no view of the road ahead (mean, 34.6%) compared to passengers who could see the road ahead extremely well (mean, 12.7%). No relationships were found between the occurrence of travel sickness and temperature or time of travel. Differences in the pattern of sickness responses exhibited by coach travellers suggest: (1) habituation through greater travel regularity may occur independently of reductions in travel sickness that occur with age; (2) females are more affected by poor forward visibility than males; and (3) the incidence of travel sickness could be significantly reduced by improving the external visibility afforded to passengers.

Motion sickness: only one provocative conflict?

In reviewing the various forms of motion sickness, the classic sensory rearrangement theory has been redefined by demonstrating that only one type of conflict is necessary and sufficient to explain all different kinds of motion sickness. A mathematical description is provided from the summarizing statement that "All situations which provoke motion sickness are characterised by a condition in which the sensed vertical as determined on the basis of integrated information from the eyes, the vestibular system and the nonvestibular proprioceptors is at variance with the subjective vertical as expected from previous experience."