Demographic and Driving Performance Factors in Simulator Adaptation Syndrome

Simulation is an important option for testing at-risk drivers with medical impairments. Simulator Adaptation Syndrome (SAS), characterized by autonomic symptoms, presents a drawback to testing. This study investigated new issues regarding susceptibility of neurologically impaired drivers to SAS, scenario situations most likely to cause SAS, and effects of SAS on driver performance. Subjects were 164 drivers enrolled in larger ongoing studies of at-risk older drivers. Eighteen had Alzheimer’s disease (AD), 44 stroke, and 102 were neurologically normal controls. Experimental drives were conducted using a fixed-base high-fidelity simulator with a 150º forward field of view. Each driver completed a questionnaire immediately after driving in the simulator, rating any feelings of discomfort along nine dimensions; an overall discomfort score was calculated. Of the 164 drivers, 130 completed the full drive and 34 ended the drive early. Drivers with higher overall discomfort scores were more likely to drop out before completing a drive. Specific symptoms strongly predicted dropping out, namely dizziness, nervousness, light-headedness, body temperature increase, and nausea. Simulator dropout rates and reported discomfort scores were significantly greater in women than men, but did not differ between drivers with AD or stroke and neurologically normal drivers. Comparisons between 32 Dropouts and 32 Non-Dropouts (matched by age, gender, neurological impairment, and scenario driven) showed no evidence that higher levels of discomfort cause a driver to perform atypically before the point of dropout. We could relate dropout to specific segments and events in the drive that required abrupt braking

Optometric Measurements Predict Performance but Not Comfort on a Virtual Object Placement Task With a Stereoscopic 3D Display

Twelve participants were tested on a simple virtual object precision placement task while viewing a stereoscopic 3D (S3D) display. Inclusion criteria included uncorrected or best corrected vision of 20/20 or better in each eye and stereopsis of at least 40 arc sec using the Titmus stereo test. Additionally, binocular function was assessed, including measurements of distant and near phoria (horizontal and vertical) and distant and near horizontal fusion ranges using standard optometric clinical techniques. Before each of six 30 minute experimental sessions, measurements of phoria and fusion ranges were repeated using a Keystone View Telebinocular and an S3D display, respectively. All participants completed experimental sessions in which the task required the precision placement of a virtual object in depth at the same location as a target object. Subjective discomfort was assessed using the Simulator Sickness Questionnaire (SSQ). Individual placement accuracy in S3D trials was significantly correlated with several of the binocular screening outcomes: viewers with larger convergent fusion ranges (measured at near distance), larger total fusion ranges (convergent plus divergent ranges, measured at near distance), and/or lower (better) stereoscopic acuity thresholds were more accurate on the placement task. No screening measures were predictive of subjective discomfort, perhaps due to the low levels of discomfort induced

Visual motion processing in migraine: enhanced motion after-effects are related to display contrast, visual symptoms, visual triggers and attack frequency

BACKGROUND: Visual after-effects are illusions that occur after prolonged viewing of visual displays. The motion after-effect (MAE), for example, is an illusory impression of motion after viewing moving displays: subsequently, stationary displays appear to drift in the opposite direction. After-effects have been used extensively in basic vision research and in clinical settings, and are enhanced in migraine. OBJECTIVES: To assess associations between (1) MAE duration and visual symptoms experienced during/between migraine/headache attacks, and (2) visual stimuli reported as migraine/headache triggers. METHODS: The MAE was elicited after viewing motion for 45 seconds. MAE duration was tested for three test contrast displays (high, medium, low). Participants also completed a headache questionnaire that included migraine/headache triggers. RESULTS: For each test contrast, the MAE was prolonged in migraine. MAE duration was associated with photophobia; visual triggers (flicker, striped patterns); and migraine or headache frequency. CONCLUSIONS: Group differences on various visual tasks have been attributed to abnormal cortical processing in migraine, such as hyperexcitability, heightened responsiveness and/or a lack of intra-cortical inhibition. The results are not consistent with hyperexcitability simply from a general lack of inhibition. Alternative multi-stage models are discussed and suggestions for further research are recommended, including visual tests in clinical assessments/clinical trials

The Effects of Primary and Secondary Task Workloads on Cybersickness in Immersive Virtual Active Exploration Experiences

Virtual reality (VR) technology promises to transform humanity. The technology enables users to explore and interact with computer-generated environments that can be simulated to approximate or deviate from reality. This creates an endless number of ways to propitiously apply the technology in our lives. It follows that large technological conglomerates are pushing for the widespread adoption of VR, financing the creation of the Metaverse - a hypothetical representation of the next iteration of the internet. Even with VR technology\u27s continuous growth, its widespread adoption remains long overdue. This can largely be attributed to an affliction called cybersickness, an analog to motion sickness, which often manifests in users as an undesirable side-effect of VR experiences, inhibiting its sustained usage. This makes it highly important to study factors related to the malady. The tasks performed in a simulated environment provide context, purpose, and meaning to the experience. Active exploration experiences afford users control over their motion, primarily allowing them to navigate through an environment. While navigating, users may also have to engage in secondary tasks that can be distracting. These navigation and distraction tasks differ in terms of the source and magnitude of attentional demands involved, potentially influencing how cyber-sickening a simulation can be. Given the sparse literature in this area, this dissertation sets out to investigate how the interplay between these factors impacts the onset and severity of sickness, thereby contributing to the knowledge base on how the attentional demands associated with the tasks performed during navigation affect cybersickness in virtual reality

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

Visual Search and Visual Discomfort

Certain visual stimuli evoke perceptions of discomfort in non-clinical populations. We investigated the impact of stimuli previously judged as uncomfortable by non-clinical populations on a visual search task. One stimulus that has been shown to affect discomfort judgments is noise that has been filtered to have particular statistical properties (Juricevic et al, 2010 Perception39 884–899). A second type of stimulus associated with visual discomfort is striped patterns (Wilkins et al, 1984 Brain107 989–1017). These stimuli were used as backgrounds in a visual search task, to determine their influence on search performance. Results showed that, while striped backgrounds did have an impact on visual search performance, this depended on the similarity between the target and background in orientation and spatial frequency. We found no evidence for a more generalised effect of discomfort on performance

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 203

This bibliography lists 150 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1980

Aerospace Medicine and Biology: A continuing bibliography with indexes (supplement 133)

This special bibliography lists 276 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System in September 1974