Motion sickness (MS) is a stressor commonly attributed with causing serious navigational and performance errors. The distinct nature of MS suggests this state may have distinct neural markers distinguishable from other states known to affect performance (e.g., stress, fatigue, sleep deprivation, high workload). This pilot study used new high-resolution electro-encephalograph (EEG) technologies to identify distinct neuronal activation changes that occur during MS. Brain EEG activity was monitored while subjects performed a ball-tracking task and viewed stimuli on a projection screen intended to induce motion sickness/spatial disorientation. Results show the presence of EEG spectral changes in all subjects who developed motion sickness when compared to baseline levels. These changes included: 1) low frequency (1 to 10 Hz) changes that may reflect oculomotor movements rather than intra-cerebral sources; 2) increased spectral power across all frequencies (attributable to increased scalp conductivity related to sweating), 3) local increases of power spectra in the 20-50 Hz range (likely attributable to external muscles on the skull) and; 4) a central posterior (occipital) independent component that shows suppression of a 20 Hz peak in the MS condition when compared to baseline. Further research is necessary to refine neural markers, characterize their origin and physiology, to distinguish between motion sickness and other states and to enable markers to be used for operator state monitoring and the designing of interventions for motion sickness.
Personnel are often required to perform multiple simultaneous tasks at the limits of their cognitive capacity. In research surrounding cognitive performance resources for tasks during stress and high cognitive workload, one area of deficiency is measurement of individual differences. To determine the amount of attentional demand a stressor places on a subject, one must first know that all subjects are performing at the same level with the same amount of available capacity in the control condition. By equating the baselines of performance across all subjects (“baselining”) we can control for differing amounts of performance capacity or attentional resources in each individual. For example, a given level of task performance without a time restriction may be equated across subjects to account for attentional resources. Training to a fixed level of proficiency with time limits might obliterate individual differences in mental resources. Eye movement parameters may serve as a real-time measure of attentional demand. In implementing a baselining technique to control for individual differences, eye movement behaviors will be associated with the true cognitive demands of task loading or other stressors. Using eye movement data as a proxy for attentional state, it may be possible to “close the loop” on the human-machine system, providing a means by which the system can adapt to the attentional state of the human operator. In our presentation, eye movement data will be shown with and without the benefit of the baselining technique. Experimental results will be discussed within the context of this theoretical framework.
With the advent of mass distribution of consumer VR games comes an imperative to set health and safety standards for the hardware and software used to deliver stereographic content. This is particularly important for game developers who intend to present this stereographic content via head-mounted display (HMD). The visual discomfort that is commonly reported by the user of HMD-based VR games presumably could be kept to a minimum if game developers were provided with standards for the display of stereographic imagery. In this paper, we draw upon both results of research in binocular vision and practical methods from clinical optometry to develop some technical guidelines for programming stereographic games that have the end user's comfort and safety in mind. This paper will provide generate strategies for user- centered implementation of 3D virtual worlds, as well as pictorial examples demonstrating a natural means for rendering stereographic imagery more comfortable to view in games employing first-person perspective.