An experimental therapy based on virtual reality (VR) computer simulations has helped persons with acroophobia reduce their fear of heights, a team of computer scientists and clinical psychologists reports in the April issue of the American Journal of Psychiatry. The study is believed to be the first controlled use of VR for treating a behavioral disorder.

The study may open new possibilities for dealing with a broad range of phobic conditions whose treatment now relies on exposure to real anxiety-producing situations. It also demonstrates a promising new application for VR, which has been popularized through games and entertainment uses.

"This study is important in establishing that there is real potential for the use of virtual reality in exposure therapy," said Dr. Larry F. Hodges, Associate Professor in the College of Computing at the Georgia Institute of Technology. "There are a range of conditions for which you might one day use virtual reality systems in a clinician's office to provide therapy."

A research team, led by Hodges and Dr. Barbara O. Rothbaum, Assistant Professor in the Department of Psychiatry in Emory University's School of Medicine, studied the effects of VR-based therapy on a group of 10 college students who displayed clear clinical signs of acrophobia.

After two months of weekly treatments, the students were evaluated for their anxiety, avoidance, attitudes and distress when confronted with height situations. They were then compared to seven students with acrophobia who did not receive treatment.

"Significant differences between the students who completed the virtual reality treatment and those on the (control) waiting list were found on all measures," the authors said. "The treatment group was significantly improved after eight weeks, but the comparison group was unchanged."

In a series of sessions conducted by a clinical therapist, the treatment group used head-mounted VR displays to view a series of anxiety-producing scenes from bridges, balconies and an open glass hotel atrium elevator. In each case, the subjects becan at ground level and moved gradually higher in the simulated scenes until they showed or reported signs of distress. The subjects would then remain at that level until their anxiety levels dropped.

During 35-45 minutes sessions held in Georgia Tech's Graphics, Visualization & Usability Center, nearly all of the students felt the sweaty palms, rubbery knees, nausea and dizziness that are the signs of acrophobia. Ultimately, all test subjects mastered the three environments, including what became known as the "Indiana Jones" bridge suspended a simulated 80 meters above a river.

In addition to the treatment, seven of the 10 students in the treatment group chose to expose themselves to height situations between sessions, even though they were not specifically instructed to do so.

"We had a subject who actually went to the (Atlanta) Marriott Marquis Hotel and got on an opoen glass elevator," noted Hodges. "He came back and told us that although he was scared, he could now deal with the situation. Before the treatment, it would have taken several people to carry him onto the elevator."

Hodges said that although the virtual situation created real anxiety and distress in the test subjects, the levels may not have been as intense as if the subjects had been on a real bridge, balcony or elevator.

"They experienced the same feelings of anxiety and the same emotions that they would in real height situations, and that seemed to be true throughout all the eight weeks of the therapy," he explained. "But people were willing to place themselves into situations in VR that they would never do in the real world. It's not as real as real-life, but it's real enough that you experience the same kind of emotions."

Though the researchers demonstrated that their VR technique could lessen the subjects' fear of heights, they did not directly compare the results to those of traditional therapy techniques. Even if the VR technique turns out to be no more effective than conventional methods, however, it may still offer significant advantages.

"Virtual reality graded exposure may turn out to be much more time- and cost-effective than traditional exposure therapy, which requires the therapist to leave the office setting and work with patients in anxiety-producing height situations," noted Rothbaum. VR treatment in a therapist's office would also protect the confidentiality of the subjects.

In addition to demonstrating the effectiveness of VR in treating psychological conditions, the study also provided information on the amount of visual data required to make subjects feel that they are really in the situation they fear. Reducing the amount of visual information could allow the VR to be done on less costly equipment, making it possible for therapists to purchase the computers and helmet-mount display for as little as $20,000, Hodges believes.

"This study allowed us to get some experimental data on the experience of what we call 'presence', and what it is that makes you feel you are in any environment," he explained. "It will help us learn what kinds of details we can abstract away and what details are important."

Other authors of the study included Rob Kooper in Georgia Tech's College of Computing, Dan Opdyke from the Department of Psychology at Georgia State University, Dr. James S. Williford of the 101st Airborne Division at Fort Campbell, KY, and Max North, of the Department of Computer Science of Clark Atlanta Univeristy.

The research was supported in part by a grant from the Emory/Georgia Tech Biotechnology Research Center, by an equipment grant from the Georgia Tech Foundation, and by a Research Experiences for Undergraduates Site Grant from the National Science Foundation.