North, 'Relative Effectiveness of Virtual Environment Desensitization and Imaginal Desensitization in the Treatment of Aerophobia', Arachnet Electronic Journal on Virtual Culture v2n04 (September 27, 1994) URL = http://hegel.lib.ncsu.edu/stacks/serials/aejvc/aejvc-v2n04-north-relative The Arachnet Electronic Journal on Virtual Culture __________________________________________________________________ ISSN 1068-5723 September 27, 1994 Volume 2 Issue 4 EJVCV2N4 NORTH Relative Effectiveness of Virtual Environment Desensitization and Imaginal Desensitization in the Treatment of Aerophobia Max North max@acm.org Sarah M. North snorth@auc.cua.edu Human Computer Interaction Group Clark Atlantic University Atlanta, Georgia 30314 Abstract Aerophobia can be defined as fear of air traveling which is classified under agoraphobia, fear of being in places or situation from which escape might be difficult (or embarrassing). Imaginal and in vivo systematic desensitization (SD) have been effective in the treatment of agoraphobia (e.g., aerophobia). Current computer and display technology allows the creation of virtual environments (VEs); VEs can provide an important intermediate step between imaginal systematic desensitization and self-directed maintenance in vivo SD. As in vivo SD provides stimuli for the patient who cannot imagine well, VEs based on stereoscopic head-mounted displays with head-tracking will produce visual and auditory stimuli. Unlike the in vivo technique VEs will allow therapist-assisted SD within the confines of a clinician's office, thus avoiding public embarrassment and violation of patient confidentiality. VE adds the advantage of greater control over graded exposure stimulus parameters and the ability to isolate which virtual stimulus parameters are essential in generating a phobic response, as well as greater efficiency and economy in delivering the equivalent of in vivo exposure within the therapist's office. This study assesses the relative effectiveness of virtual environment imaginal systematic desensitization (VEISD) and imaginal systematic desensitization (ISD) in treatment of aerophobia. The preliminary results of the pilot case studies so far are very encouraging. INTRODUCTION Aerophobia is classified as a simple phobia in the Diagnostic and Statistical Manual of Mental Disorders [1]. People having this disorder suffer from marked distress about having the fear or from significant behavior difficulties. Behavior dysfunction involves interference with normal routine or with interpersonal relationships. There have been relatively few publications of controlled research on the therapy of aerophobia. Behavioral therapy has included exposing the subject to anxiety producing stimuli. These stimuli are generated through a variety of modalities including imaginal (subject generates stimulus via imagination) and in vivo [6]. In a controlled study, imaginal desensitization and negative practice (subject practices anxiety response) were demonstrated to be equally effective in the treatment of agoraphobia [5]. In addition to current in vivo and imaginal modalities, virtual environments (VEs) can also generate stimuli that will be utilized in desensitization therapy. Like in vivo therapy, VE systematic desensitization (VEISD) therapy will provide stimuli for patients who cannot imagine well. VEISD will be used as an intermediate step in preparing patients for maintenance therapy involving self-directed in vivo exposure. VIRTUAL ENVIRONMENTS Virtual Environments (VEs) offer a new human-computer interaction paradigm in which users are no longer simply external observers of data or images on a computer screen but are active participants within a computer-generated three-dimensional virtual word. Virtual environments differ from traditional displays in that computer graphics and various display and input technologies are integrated to give the user a sense of presence or immersion in the virtual environment [7]. There are several approaches to creating virtual environments. Head-mounted displays consist of separate display screens for each eye that are attached to the head along with some type of display optics and a head-tracking device [8]. Time-multiplexed CRT displays present a stereoscopic image by alternating right-and left-eye view of a scene on a CRT. The image is viewed through a shutter system that occludes the left eye when the right-eye image is on the screen and vice versa [4]. Time-multiplexed projection displays operate similarly to time-multiplexed CRTs, but the images are projected onto one or more large screens [3]. Projection and CRT stereoscopic displays may or may not also incorporate head-tracking. Virtual environments also provide special techniques that allow users to interact with virtual spaces. Current techniques include the use of special gloves that track hand and finger positions so that the user can grasp virtual objects, six-degrees-of-freedom mouse and navigation devices, and locomotive devices such as treadmills, bicycles, or "flying" chairs that allow users to move about in the environment [2]. The virtual environment for this study consist of a stereoscopic head-mounted display (VR Flight Helmet), an electromagnetic head-tracker (Ascension Technology Bird), and a glove (Virtual Technologies CyberGlove) worn by the user for interacting with objects in the virtual environment. This arrangement allows for time-parallel stereoscopic display with visual panning controlled by head movement in all virtual directions. METHODOLOGY The subject pool for this study consist of select group of males and females undergraduate students who are enrolled in an undergraduate general psychology course. Subjects having symptoms limited to aerophobia and consistent with the diagnosis of simple phobia [1] are included in the study. After obtaining informed consents, subjects are randomly assigned to three treatment conditions: imaginal systematic desensitization (ISD), VEISD, and control group. In the first treatment session, the ISD subjects are asked to rank order a list of the aerophobia situations according to the degree of anxiety arousal. These hierarchies are used for the ISD [5]. Then, they meet as a group for 45 minutes of relaxation training. During the VEISD subjects' first session, they are familiarized, as a group, with the VE equipment. Then, they receive 45 minutes of relaxation training as a group. For the VEISD and ISD subjects' subsequent sessions, individual SD therapy are conducted in a standard format. The computer program designed for VEISD generates a standard hierarchy of aerophobia situations to be presented at the same rate in VEISD and ISD. Assessment measures are administered under blind conditions and in a standard order. At one month post treatment, all subjects are asked to complete a nine-point rating scale (including degrees for worsening symptoms) rating the degree to which their aerophobia symptoms have changed since pre-treatment test (Improvement Rating Scale). ACKNOWLEDGEMENT This project is an ongoing research project by the Human-Computer Interaction Group that is partially supported by the U.S. Army Center of Excellence in Information Science (Contract Number DAAL03-92-6-0377). The views contained in this document are those of the authors and should not be interpreted as representing the official policies of the U.S. Government, either expressed or implied. REFERENCES 1. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders. 3rd Edition, Revised. Washington, D. C. American Psychiatric Association, (1987), 243-245. 2. Bryson, Steve. Survey of Virtual Environments and Techniques. ACM SIGGRAPH 92 Course Notes, Chicago. 3. Cruz-Neira, Sandin, D.J., DeFanti, T.A., Kenyon, R.V., Hart, J.C. The CAVE:audio visual experience automatic virtual environment. Communications ACM, 35, 6(1992), 64-72. 4. Hodges, L.F. Time-multiplexed Stereoscopic Computer Graphics. IEEE Computer Graphics and Applications 12,2 (1992), 20-30. 5. Pendleton, M.G. and Higgins, R.L. A Comparison of Negative Practice and Systematic Desensitization in the Treatment of Acrophobia. Journal of Behavior Therapy & Experimental Psychiatry. 114,4(1983), 317-323. 6. Schneider, J.W. Lens-assisted IN VIVO Desensitization to Heights. Journal of Behavior Therapy & Experimental Psychiatry. 13,4 (1982), 333-336. 7. Sheridan, T.B. Musings on Telepresence and Virtual Presence. Presence: Teleoperators and Virtual Environments. 1,1 (1992), 120-125. 8. Teitel, M.A. The Eyephone: A Head-Mounted Stereo Display. SPIE Proc. 1256, (1990), 168-171. Table of Contents _______________________ The Virtual Square ================== edited by James Shimabukuro (jamess@uhunix.uhcc.Hawaii.Edu) The Virtual Square is devoted to non-refereed opinion columns and essays. 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