Aufbau eines medizinischen Virtual Reality-Labors und Entwicklung eines VR-gestützten neuropsychologischen Testsystems mit einer präklinischen und klinischen Evaluationsstudie

Abstract

Background: Virtual Reality (VR) is a promising technology in the field of medicine and neuroscience. E.g. in neuropsychological testing, paper & pencil tests may be replaced in future by VR tests which provide a better validity. In clinical use, diffusion of VR technology is still limited because of high costs for equipment and serious concerns about side effects during VR use with patients.Objectives: Development of an interdisciplinary medical VR laboratory at the University of Goettingen. As pilot project, the development and evaluation of a neuropsychological test system for visuospatial learning and topographical orientation was planned. In this context, usability, effects and side effects of VR had to be analysed.Methods: A technical analysis of existing VR equipment and medical VR applications was the first step for choosing the adequate techniques for the VR lab. Based on a structured system design, a VR supported neuropsychological test system was designed. For evaluation of the test system, a pre-clinical (PILOT; 22 healthy subjects) and clinical study (CLINIC; 75 healthy subjects, 40 before / 25 after surgery for intractable epilepsy, 27 patients w. stroke, 48 patients with suspected Alzheimer s disease) was performed. Side effects were documented with the Simulator Sickness Questionnaire (SSQ). A post-test questionnaire was administered regarding usability, immersion and realism. The results were examined statistically to identify possible factors regarding the occurrence of side effects.Results: A PC-based virtual reality laboratory was established with the possibility of desktop (monitor) or immersive (head mounted display, HMD) VR. The neuropsychological test system was realized including tests for visual-spatial and topographical learning and executive memory. In the PILOT study, no user preference for any display type was observed. The initial HMD (VirtualResearch V8) was not suitable for use on a daily base with patients and was replaced in the CLINIC study by a light-weighted commercial HMD (Sony Glasstron). In total, few user problems were observed. No display type offered a significant advantage in terms of immersion and realism. 1.4% (CLINIC) to 4.8% (PILOT) of the participants cancelled the VR test because of side effects. Regarding the SSQ scores, only the disorientation-subscore showed a significant increase during testing (CLINIC). Further analyses revealed the HMD not the projection or desktop display mode as a significant facto! r for an increase of SSQ Scores during testing. No influence of gender, age, group (healthy subjects, patients) on the SSQ scores during the test course could be observed. In general, females showed significantly higher SSQ scores unrelated to the test course.Conclusion: Technically and from a organisational point of view the PC based VR lab proofed to be an economical and efficient concept. For a first time, side effects were analysed for a clinical project in the field of neuroscience. Safety of the test system for patients in non-immersive condition could be demonstrated, but the results of this study cannot be generalized for other applications. A substantial advantage of an immersive display interfaces (HMD) in comparison to less-immersive standard displays could not be demonstrated, on the contrary the incidence of side effects seemed to be higher. Due to ethical, legal and economical reasons the use of VR technology in clinical settings should be carefully evaluated for each application.