Creation of a Virtual Interface for Stress-Trauma Investigations through Open World Navigation: An Exploration of Tolerability and Physiological Reactions
Abstract
It is estimated that as many as 50% of people suffering from Whiplash Associated Disorders (WAD) may experience chronic alterations of their activities of daily living as much as 1-year post injury. Despite their burden, there is little to evidence to suggest why some people may be more likely to acquire WAD or develop chronic symptomology. Additionally, the link between biomechanical forces at the time of impact and symptom development or recovery is poor. As a result, interest in alternative theories such as stress system reactivity have received interest in recent literature, but empirical methods to test them has been lacking. Thus, the purpose of this thesis was to explore the relationship between stress and trauma using a known stressor and a newly developed virtual reality (VR)-based car crash simulator to better understand the immediate reaction to being involved in a motor vehicle crash (MVC). In Chapter 2, we evaluated conditioned pain modulation (CPM) in reaction to the cold pressor task and measured associations with indices of sympathetic and hypothalamic-pituitary-adrenal function. It was found that only 30% of participants experienced inhibitory CPM. Within this group, there was a positive moderate correlation between CPM and the absolute change in skin conductance pre-to-post cold pressor task. In Chapter 3, we explored the initial tolerability to a novel VR-based car crash simulator in healthy subjects and also evaluated sense of presence and simulator sickness. The system was well tolerated by a majority of participants, and it appeared that the sense of presence and simulator sickness shared an inverse relationship. In Chapter 4, we evaluated the pain and stress response to our VR-based car crash simulator in the form of pain pressure detection thresholds, CPM, heart rate variability, and salivary cortisol. Over 40% of participants were more sensitive to pain following the simulation, and this may have been associated with an increase in parasympathetic nervous system activity and salivary cortisol. These results may help to explain some of the heterogeneity of WAD presentations after a MVC and signify that the pain/stress response to simulated trauma is variable.