Computer-based virtual reality technology has evolved to the point at which medical simulation can be incorporated into medical education and into the eventual objective evaluation of surgical competence. Flight simulation provides a model for examining the role of computer-based simulation in medical training and certification. The plan by which medical simulators are being designed and validated for surgical training is presented, as is a description of the current state of medical simulation and the limitations of the technology. A realistic argument for adoption is suggested that takes into account lower price constraints, technological limitations, and professional barriers to the implementation of simulator-based training and accreditation. 1

Flight simulators are examples of virtual environment (VE) systems that often give rise to a form of discomfort resembling classical motion sickness. The major difference between simulator sickness and other forms of motion sickness is that the former exhibits more oculomotor-related symptoms and far less actual vomiting. VEs of the future are likely to include more compellingly realistic visual display systems, and these systems can also be expected to produce adverse symptoms. The implications of simulator sickness for future uses of VEs include adverse consequences for users' safety and health, user acceptance, training effectiveness, and overall system performance. Based on data from a factor analysis of over 1000 Navy and Marine Corps pilot simulation exposures, a new scoring procedure for simulator sickness has recently been developed (Lane & Kennedy, 1988; Kennedy, Lane, Berbaum, & Lilienthal, 1992). The factor analytic scoring key provides subscales for oculomotor stress (eyestrain), nausea, and disorientation. Simulators are being examined in terms of these factor profiles to identify causes of simulator sickness. This approach could also be used in evaluating motion sickness-like symptomatology that occurs in connection with the use of VEs. This paper describes the use of the multifactor scoring of the Simulator Sickness Questionnaire (SSQ) in diagnosing sources of simulator sickness in individual simulators. Reanalysis by this new methodology was employed to standardize existing simulator sickness survey data and to determine whether relationships existed that were missed by the more traditional scoring approaches.

Visually induced motion sickness is a syndrome that occasionally occurs when physically stationary individuals view compelling visual representations of self-motion. It may also occur when detectable lags are present between head movements and recomputation and presentation of the visual display in helmet-mounted displays. The occurrence of this malady is a critical issue for the future development and implementation of virtual environments. Applications of this emerging technology are likely to be compromised to the extent that users experience illness and/or incapacitation. This article presents an overview of what is currently known regarding the relationship between visually specified self-motion in the absence of inertial displacement and resulting illness and perceptual-motor disturbances.