Presence in Virtual Reality Exposure Therapy Systems

Presence in Virtual Reality Exposure Therapy Systems

Ling, Y.

Heynderickx, I.E.J. (promotor)

Electrical Engineering, Mathematics and Computer Science

Intelligent Systems

2014-09-03

Experiencing anxiety is essential for virtual reality exposure therapy (VRET) to be effective in curing patients suffering from anxiety disorders. However, some patients drop out in VRET due to the lack of feeling anxiety. Presence - which refers to the feeling of being in the virtual environment - has been considered an important mechanism that leads to the experience of anxiety. Therefore, understanding the relationship between presence and anxiety and finding ways to improve presence in VRET are the main aims of this thesis. To justify the research into presence, a meta-analysis on the relationship between sense of presence and anxiety over various anxiety disorders was conducted, and this analysis indeed showed a medium size association between presence and anxiety. Hence, it was important to find ways to improve presence in VRET systems by evaluating technological factors such as stereoscopy, display screen size and perspective. In addition, since patients dropped out in individual cases, it was also necessary to evaluate the impact of individual characteristics on the feelings of presence. The technological factors and individual characteristics were evaluated conducting empirical studies in virtual social environments. The results showed that presence is affected by perspective and display screen size, and thus, presence can be improved in VRET systems showing elongated virtual environments and using larger screen displays. Individual characteristics such as visual acuity and immersive tendency were related to the experienced feelings of presence, and so, patients might consider properly correcting their visual acuity when being submitted to VRET. When using head mounted displays with head tracking, however, the rendering of stereoscopy has limited practical importance for VRET in the public speaking domain, i.e., no improvement in experienced anxiety and a smaller effect on presence were found for stereoscopy as compared to other display technologies. This finding therefore does not warrant the use of rendering stereoscopy in head mounted displays with head tracking for public speaking domain. To conclude, the results presented in this thesis offer opportunities to improve experienced presence, and as such, is anticipated to reduce the dropout rate of patients in VRET by optimizing the perspective view of the virtual environment and by considering personal characteristics of the patients such as immersive tendency and visual ability.

presence
virtual reality exposure therapy
individual characteristics
stereoscopy
perspective
meta-analysis

https://doi.org/10.4233/uuid:6c095bf6-f841-4df5-a62a-c94d2f59036c

2014-09-03

9789462036352

Institutional Repository

doctoral thesis

(c) 2014 Ling, Y.