Sarah Nichols

Bio: Sarah Nichols is an academic researcher from University of Nottingham. The author has contributed to research in topics: Virtual reality & Usability. The author has an hindex of 12, co-authored 25 publications receiving 1239 citations.

Virtual Reality-Induced Symptoms and Effects (VRISE)

Abstract: An experimental program of research was carried out to assess the potential health and safety effects of participating in virtual environments (VEs) via head-mounted displays (HMDs) This paper presents the results obtained from nine experiments examining the effects experienced during and after participation in a variety of VR systems, VE designs, and task requirements, for a total participant sample of 148 individuals A combination of methods including self-report scales, performance measures, physiological indicators, observation, interview, and user attitude/opinion questionnaires were used to measure simulator (VE) sickness, postural instability, psychomotor control, perceptual judgment, concentration, stress, and ergonomics effects Greatest effects across the different systems, VEs, and exposure times were found for sickness symptoms and physiological measures, with some concern over postural instability and physical ergonomics, also Although many of the effects were relatively minor and short lived, they were serious for five percent of participants and irritating for a considerable percentage more The aetiology of the effects is sufficiently different to that for simulators or transport systems to justify us using a new term, virtual reality-induced symptoms and effects (VRISE) Implications are drawn for VR system design, VE specification, and the ways in which industrial use of VR/VE should be planned and supported

Measurement of presence and its consequences in virtual environments

Abstract: A sense of presence is one of the critical components required by any effective virtual environment (VE). In contrast, side effects such as sickness may be produced in some virtual environments, detracting from the enjoyment or usefulness of the VE and from subsequent performance of the participant. Both presence and sickness in virtual environments are multifactorial phenomena not easily amenable to understanding or measurement. The first experiment reported here compares use of direct performance measures and rating scales to assess presence, whilst varying the VE display medium (head mounted and desktop displays) and whether or not sound was used in the VE. The second experiment addresses associations between presence, sickness and enjoyment of virtual environment participation. There was enough comparability between a reflex response within the VE and the rating scales to justify future exploration of the former measure of presence. A number of explanations are given for the partial association found between presence and sickness.

Virtual environments for motor rehabilitation: review.

Abstract: In this paper, the current "state of the art" for virtual reality (VR) applications in the field of motor rehabilitation is reviewed. The paper begins with a brief overview of available equipment options. Next, a discussion of the scientific rationale for use of VR in motor rehabilitation is provided. Finally, the major portion of the paper describes the various VR systems that have been developed for use with patients, and the results of clinical studies reported to date in the literature. Areas covered include stroke rehabilitation (upper and lower extremity training, spatial and perceptual-motor training), acquired brain injury, Parkinson's disease, orthopedic rehabilitation, balance training, wheelchair mobility and functional activities of daily living training, and the newly developing field of telerehabilitation. Four major findings emerge from these studies: (1) people with disabilities appear capable of motor learning within virtual environments; (2) movements learned by people with disabilities in VR transfer to real world equivalent motor tasks in most cases, and in some cases even generalize to other untrained tasks; (3) in the few studies (n = 5) that have compared motor learning in real versus virtual environments, some advantage for VR training has been found in all cases; and (4) no occurrences of cybersickness in impaired populations have been reported to date in experiments where VR has been used to train motor abilities.

A Cross-Media Presence Questionnaire: The ITC-Sense of Presence Inventory

Abstract: The presence research community would benefit from a reliable and valid cross-media presence measure that allows results from different laboratories to be compared and a more comprehensive knowledge base to be developed. The ITC-Sense of Presence Inventory (ITC-SOPI) is a new state questionnaire measure whose development has been informed by previous research on the determinants of presence and current self-report measures. It focuses on users' experiences of media, with no reference to objective system parameters. More than 600 people completed the ITC-SOPI following an experience with one of a range of noninteractive and interactive media. Exploratory analysis (principal axis factoring) revealed four factors: Sense of Physical Space, Engagement, Ecological Validity, and Negative Effects. Relations between the factors and the consistency of the factor structure with others reported in the literature are discussed. Preliminary analyses described here demonstrate that the ITC-SOPI is reliable and valid, but more rigorous testing of its psychometric properties and applicability to interactive virtual environments is required. Subject to satisfactory confirmatory analyses, the ITC-SOPI will offer researchers using a range of media systems a tool with which to measure four facets of a media experience that are putatively related to presence.

Current practice in measuring usability: Challenges to usability studies and research

Abstract: How to measure usability is an important question in HCI research and user interface evaluation. We review current practice in measuring usability by categorizing and discussing usability measures from 180 studies published in core HCI journals and proceedings. The discussion distinguish several problems with the measures, including whether they actually measure usability, if they cover usability broadly, how they are reasoned about, and if they meet recommendations on how to measure usability. In many studies, the choice of and reasoning about usability measures fall short of a valid and reliable account of usability as quality-in-use of the user interface being studied. Based on the review, we discuss challenges for studies of usability and for research into how to measure usability. The challenges are to distinguish and empirically compare subjective and objective measures of usability; to focus on developing and employing measures of learning and retention; to study long-term use and usability; to extend measures of satisfaction beyond post-use questionnaires; to validate and standardize the host of subjective satisfaction questionnaires used; to study correlations between usability measures as a means for validation; and to use both micro and macro tasks and corresponding measures of usability. In conclusion, we argue that increased attention to the problems identified and challenges discussed may strengthen studies of usability and usability research.

How Immersive Is Enough? A Meta-Analysis of the Effect of Immersive Technology on User Presence

Abstract: The concept of presence, or “being there” is a frequently emphasized factor in immersive mediated environments. It is often assumed that greater levels of immersive quality elicit higher levels of presence, in turn enhancing the effectiveness of a mediated experience. To investigate this assumption the current meta-analysis synthesizes decades of empirical research examining the effect of immersive system technology on user experiences of presence. Aggregating 115 effect sizes from 83 studies, it finds that technological immersion has a medium-sized effect on presence. Additionally, results show that increased levels of user-tracking, the use of stereoscopic visuals, and wider fields of view of visual displays are significantly more impactful than improvements to most other immersive system features, including quality of visual and auditory content. These findings are discussed in light of theoretical accounts of the presence construct as well as practical implications for design.

Redirected walking

Abstract: There are many different techniques for allowing users to specify locomotion in human-scale, immersive virtual environments. These include flying with a hand-controller, using a treadmill, walking-in-place, and others. Real walking, where the user actually and physically walks in the lab, and virtually moves the same distance and in the same direction in the virtual scene, is better than flying. It is more input-natural, does not require learning a new interface, results in a greater sense of presence, and theoretically results in less simulator sickness. One serious problem with real walking, however, is that the size of the virtual scene is limited by the size of tracked area. For example, for an architect to really walk in a virtual prototype of a house, the tracked area must be as large as the house. This requirement makes real walking infeasible for many facilities and virtual scenes. To address this limitation, I have developed Redirected Walking, which by interactively and imperceptibly rotating the virtual scene around her, makes the user turn herself. Under the right conditions, Redirected Walking would cause the user to unknowingly walk in circles in the lab, while thinking she is walking in a straight and infinitely long path in the virtual scene. In this dissertation I develop Redirection, discuss its theoretical and physiological underpinnings, and presents results to show that it can be used: (1) to make the user turn themselves, (2) without causing the user to be aware of Redirection, (3) without unacceptably increasing the user's level of simulator sickness and, most importantly, (4) to useful effect: (A) In head-mounted display systems, the user can experience a virtual scene larger than the lab while also having the benefits of real walking. (B) In an open-backed, three-walled CAVE, users can have the increased presence and input-naturalness normally associated with a fully enclosed CAVE. I also present guidelines for VE practitioners wishing to use Redirection, based on the theory and observations reported in this dissertation.