eTher – An Assistive Virtual Agent for Acrophobia Therapy in Virtual Reality

Abstract

This paper presents the design, a pilot implementation and validation of eTher, an assistive virtual agent for acrophobia therapy in a Virtual Reality environment that depicts a mountain landscape and contains a ride by cable car. eTher acts as a virtual therapist, offering support and encouragement to the patient. It directly interacts with the user and changes its voice parameters – pitch, tempo and volume – according to the patient’s emotional state. eTher identifies the levels of relaxation/anxiety compared to a baseline resting recording and provides three modalities of relaxation - by determining the user to look at a favorite picture, listen to an enjoyable song or read an inspirational quote. If the relaxation modalities fail to be effective, the virtual agent automatically lowers the level of exposure. We have validated our approach with a number of 10 users who played the game once without eTher’s intervention and three times with assistance from eTher. The results showed that the participants succeeded to finish the game quicker in the last gameplay session where the virtual agent intervened. Moreover, their biophysical data showed significant improvements in terms of relaxation state.