3D Audio for Virtual Reality Exposure Therapy

Virtual Reality Exposure Therapy (VRET) is an effective method to treat anxiety disorders and comes with many advantages over exposure in vivo, the latter being exposure in real-life. VRET is done by exposing patients gradually with their fear by using immersive virtual environments (VEs). Most attention in VRET research goes to visuals and less to audio, haptics, smell and taste. This report focuses on the use of audio, and in particular on 3D audio, in VRET systems. 3D audio is the only audio technique that is able to reproduce sounds as they are heard in real-life. Unlike other audio techniques, 3D audio uses a model of the human hearing in order to replicate accurate horizontal (azimuth), vertical (elevation) and distance information cues. Audio, especially combined with other modalities like vision, provides added value in terms of immersion. Audio is also indicated to have a significant effect on presence and presence is assumed to be a key factor in VRET performance. This report discusses if 3D audio can create more presence, anxiety and spatial perception compared to other commercially available audio techniques. This was done by doing three experiments, using stimuli of a flying wasp in order to generate a global sense of anxiety and/or discomfort. All audio was represented using headphones. Results indicate that people are able to hear differences in a direct comparison between 3D audio and mono, stereo and dolby headphones for the given wasp stimuli. People also report more presence and anxiety for 3D audio without the addition of visual information, but they don't focus on these differences anymore as soon as visual information is added to the audio. This is probably because the audio is overruled by the visuals when combining the information. Vision is known to be the dominant sense, and when combining audio with visuals, visuals "take over". As a consequence, different audio techniques may result in a similar experience. Suggestions are done for future research and it is currently advised to use stereo audio in a VRET system until future research shows otherwise. It is also stated that it may be more effective to increase the number of matching modalities instead of optimizing only one in particular.Media & Knowledge EngineeringInteractive IntelligenceElectrical Engineering, Mathematics and Computer Scienc