From: "Eugenia M. Kolasinski" <104550.2042@COMPUSERVE.COM> Subject: HUMAN-FACTORS: Three things on simulator sickness Date: Sat, 3 Aug 1996 22:23:19 -0400 Message-ID: <199608032223_MC1-822-A052@compuserve.com> Hi all! Three things for you: (1) I am very proud to announce that this past May, I received my Ph.D. in Human Factors Psychology from the University of Central Florida. My Dissertation - Prediction of Simulator Sickness in a Virtual Environment - is available on the World Wide Web at http://www.hitl.washington.edu/projects/vestibular/kolasinski/ . Hard copies are available through University Microfilms International at 1-800-521-0600x2157 (document No. 96-21485). I have included the abstract for the Dissertation at the end of this message after the signature block for your perusal. If you have any questions regarding my research, please feel free to contact me. BTW, even if you are not interested in the Dissertation itself, the Web site is worth checking out just to see the *fabulous* job Toni Emerson at HITL did with putting it on the Web. Thanks for the great work, Toni! (2) A while ago, Toni was looking for studies on the effects of long-term immersion in HMDs. While doing the literature review for the Dissertation, I did not come across any such research specific to VR. In flight simulators, pilots are often subjected to very long exposures, usually about 2 hours. To my knowledge, no studies have been conducted to experimentally investigate the effects of long-term immersion in HMD's. I would also like to reiterate the point made by Dr. Wann regarding the ethical issues which may be associated with conducting such research. I know that my own research underwent close scrutiny before it received Human Subjects approval and many precautions were taken to thoroughly ensure the safety of my participants. Furthermore, research involving long-term immersion may be especially problematic because of the possible increased risk of ataxia (i.e., postural instability) which may be associated with longer exposures. (For studies of ataxia with flight simulators, see Fowlkes, Kennedy, & Lilienthal, 1987; and Kennedy, Fowlkes, & Lilienthal, 1993.) (3) Finally, Hartwig Distler posted a message a while ago concerning possible simulator sickness issues associated with a simulation environment he set up involving a modified bicycle. He was considering adding a vibration unit to the system with the logic that it might "keep the vestibular system busy" and, possibly, alleviate sickness. It is interesting that you suggest this, Hartwig, because that is exactly what was suggested should be added to early fixed-based simulators to alleviate sickness. Casali (1986) reviews literature which found that, even with random vibration, sickness still occurred so you probably should not expect any miracle cures in your situation either. Furthermore, research by Wendt and his colleagues in the 1940's found that Very Low Frequency vertical oscillation in the (approximate) range of 0.2-0.3 Hz is especially nauseogenic for humans, so I would definitely recommend avoiding that frequency (unless you wish to study the phenomenon of sickness, in which case, please give me a call! :-) ) Thus, the motion itself could actually cause true motion sickness. Furthermore, Mark Draper posted a reply warning that time lags and/or inaccuracies of the head tracking system *might* combine with the vertical VOR and result in problematic interactions. My recommendation would be to study the situations in which sickness is occurring. Perhaps you can identify some common aspects about the situations in which users are experiencing discomfort. Also, you didn't give any estimate for the rate of occurrence of sickness. Do most users experience ill effects or is it fairly rare? In any event, *PLEASE* take the time to thoroughly document and share your findings - such information is desperately needed if we are to gain any understanding at all about simulator sickness as it occurs in virtual environments. Here are my references: Casali, J.G. (1986, August). Vehicular simulation-induced sickness, Volume 1: An overview. IEOR Technical Report No. 8501. (NTSC TR 86-010). Orlando, FL: Naval Training Systems Center. Fowlkes, J.E., Kennedy, R.S., & Lilienthal, M.G. (1987). Postural disequilibrium following training flights. Proceedings of the 31st Annual Meeting of the Human Factors Society, 488-491. Kennedy, R.S., Fowlkes, J.E., & Lilienthal, M.G. (1993). Postural and performance changes following exposures to flight simulators. Aviation, Space, and Environmental Medicine, 64(10), 912-920. Sorry it has taken me so long to reply to these posts. Hope some of this information helps! %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Eugenia M. Kolasinski, Ph.D. - Human Factors Psychologist 3048-F Whisper Lake Lane Winter Park, FL 32792 email: 104550.2042@CompuServe.com Dissertation: http://www.hitl.washington.edu/projects/vestibular/kolasinski/ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Prediction Of Simulator Sickness In A Virtual Environment Eugenia M. Kolasinski, Ph.D. ABSTRACT Sickness induced by Virtual Reality (VR) devices poses a genuine threat to the viability of this new technology and its potential products. If the occurrence or severity of sickness could be successfully predicted based on characteristics of an individual, at-risk users could be identified, properly warned, and, perhaps, trained in some way to reduce their risk. A Personal Computer-based VR system was used to address the prediction of simulator sickness. Phase I investigated four characteristics of an individual - age, gender, mental rotation ability, and pre-exposure postural stability - which were hypothesized to be predictive of sickness. Sickness measured as a function of the Total Severity score from the Simulator Sickness Questionnaire (SSQ) was successfully modeled on these characteristics using linear regression techniques, leading to three major findings. First, sickness - as measured by the SSQ - did, in fact, occur in association with exposure to VR. For 35% of the participants, this sickness involved lingering effects and/or possible delayed after-effects. Second, sickness was successfully modeled on characteristics of the individual. The developed model indicated a complicated relationship between predicted sickness and gender, age, mental rotation ability, and pre-exposure postural stability. Third, based on the model developed, sickness is not predicted to differ for gender directly but, rather, gender interacts with mental rotation ability in its effect on sickness. Phase II investigated the occurrence of ataxic decrements in postural stability. No such decrements were found to be associated with the 20-minute exposure. Thus, ataxic decrements do not appear to be associated with short exposures to low-end VR. This finding, however, may be limited to VR tasks of the type used in this study. Practical implications and areas for future research are discussed. A Dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Psychology in the graduate studies program of the College of Arts and Sciences University of Central Florida Orlando, Florida Spring Term 1996 Major Professor: Richard D. Gilson, Ph.D. Committee: Advisors: David W. Abbott, Ph.D. Larry J. Hettinger, Ph.D. Robert S. Kennedy, Ph.D. Linda C. Malone, Ph.D. Kay M. Stanney, Ph.D. Thomas A. Stoffregen, Ph.D.