Exploratory factor analysis and validity of the virtual reality symptom questionnaire and computer use survey.

The widespread use of virtual reality head-mounted-displays (HMDs) calls for a re-examination of the impact of prolonged exposure to fixed visual displays at close ocular proximity. The purpose of this study is to validate the Virtual Reality Symptoms Questionnaire (VRSQ), created to understand symptoms of prolonged HMDs use, and Computer Use Survey (CUS), created to assess general physical and visual discomfort symptoms. Participants (N = 100) recorded their general discomfort symptoms using the CUS, performed an interactive task using a HMD for thirty minutes, and then answered the CUS again along with the VRSQ. VRSQ, analysed using an exploratory factor analysis, indicated a clear two-factor solution, and demonstrated very good internal consistency (α = 0.873). The CUS, also analysed using an exploratory factor analysis, indicated a four-factor solution, and demonstrated good internal consistency (α = 0.838). Practitioner Summary: A quantitative-experimental study was conducted to explore the factor structure and validate both the Virtual Reality Symptoms Questionnaire (VRSQ), and the Computer Use Survey (CUS). Findings indicate the VRSQ and CUS are precise and accurate survey instruments for evaluating discomfort after VR-HMD use and the latter for computer use. Abbreviations: VRSQ: virtual reality symptom questionnaire; CUS: computer use survey; OLED: organic light-emitting diode; MSQ: pensacola motion symptom questionnaire; SSQ: simulator sickness questionnaire; 3 D: three-dimensional computer generated space; VR: virtual reality; VR-HMD: virtual reality head-mounted-display; HMDs: head-mounted-displays; EFA: exploratory factor analysis.

A head-worn display ("smart glasses") has adverse impacts on the dynamics of lateral position control during gait.

BACKGROUND: Head-worn displays (e.g., "smart glasses") are an emerging technology to provide information, and in many situations they might be used while walking. However, little evidence exists regarding the effects of head-worn displays on walking performance. We found earlier that "smart glasses" had smaller adverse effects on measures of gait variability in the anterior-posterior direction vs. other types of information displays. Participants, however, complained about motion sickness and perceived instability while using smart glasses. RESEARCH QUESTION: Were the participants' complaints a result of adverse effects of the smart glasses on the dynamics of lateral stepping and gait stability? METHODS: Twenty individuals walked on a treadmill in four different conditions; single-task walking, and three dual-task walking conditions, the latter using smart glasses, smartphone, and a paper-based system to provide secondary cognitive tasks. We assessed the dynamics of lateral stepping and gait stability using the goal equivalent manifold and maximum Lyapunov exponent, respectively. RESULTS: The dynamics of the lateral stepping were more adversely affected using smart glasses compared to the other types of information displays. However, stability measures revealed that the participants were more unstable when they used the smartphone and paper-based system. SIGNIFICANCE: Promising results in terms of stability and adaptability suggest that head-worn display technology is a potentially useful alternative to smartphones and other types of information displays for reducing the risk of a fall. Results regarding perceptions of instability and a loss of control over lateral stepping, however, imply that this technology requires further development prior to real-work implementations.

Thermal comfort and virtual reality headsets.

This study proposed to investigate the thermal properties and subjective thermal discomfort of five virtual reality headsets, and their relationships. Twenty-seven university students used each of the five headsets for 45 min. Microclimate temperature and relative humidity were measured by miniature dataloggers. Infrared thermography was used to measure temperature distribution on the contact points between user's face and the headsets. Participants reported subjective thermal discomfort associated with using each headset. The average microclimate temperature and relative humidity increased by 7.8 °C and 3.5% respectively after headset use. Overall subjective thermal discomfort increased along with duration of use and came primarily from the display. Applying the linear mixed-effects model showed that subjective thermal discomfort is positively correlated with duration of use, microclimate temperature, relative humidity and display coverage area. Conversely, thermal discomfort is negatively correlated with total coverage area, with microclimate temperature acting as the most significant contributing factor. The headsets were ranked by pairing the objective measurements with subjective evaluations.