The purpose of this paper is to provide a comprehensive literature review of Virtual Reality Therapy (VRE) in the treatment of Post Traumatic Stress Disorder (PTSD) in combat soldiers from the Vietnam, Iraq, and Afghanistan War. Traditional exposure therapies such as imaginal or in vivo exposure introduce the possibility of avoidance, a condition inherent in PTSD, and patients may express difficulty imagining or describing their traumatic experiences in detail. However, VRE therapy eliminates this possibility because it allows participants to become immersed in a virtual environment through the incorporation of audio, visual, olfactory, and tactile stimulation in a human-computer interactive program. VRE therapy creates a multimodal experience for the participant because it taps into all sensory modalities, which essentially provokes a realistic re-creation of their traumatic experience. With VRE therapy, the therapist can match the patient's personal narrative to a virtual environment, allowing patients to confront their traumas, while assisting them in the modification of dysfunctional thoughts and beliefs to reduce PTSD symptoms.
Exposure Therapy in the Treatment of PTSD in Combat Soldiers
Post-Traumatic Stress disorder, or PTSD, is a chronic and debilitating condition that occurs in individuals who have been exposed to an extreme life threatening or a traumatic experience. According to the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association (2002), symptoms of PTSD include re-experiencing of the original trauma through nightmares or flashbacks, avoidance, and hyperarousal symptoms that severely disrupt and impair one's life. PTSD symptoms often intensify when the individual is exposed to a stimulus resembling the original trauma.
Virtual reality therapy, or VRE therapy, has been a proposed treatment option for combat veterans exhibiting Post-Traumatic Stress Disorder, or PTSD. The therapeutical approach allows patients to become immersed in a virtual environment that reflects combat veterans' region of deployment. Users do not merely observe images on a computer screen in a passive manner; in fact, they are actively participating and interacting with a computer-generated three-dimensional world that may be a virtual reconstruction of the content and environment that may resemble their original trauma. Practitioners can readily administer the computer-generated environment to the patient within the office and customize the stimuli and situations to each individual case, so that it will resemble the original trauma, and empower the patient to take control of the memory.
VRE therapy allows the patient to become engage more emotionally, rather than having to recount an experience mentally, which may result in the recall of the trauma in a flat, numb, or emotionless manner, resulting in an avoidance of the situation. Traditional exposure therapies require that the patient imagine the traumatic experience through memory in as vivid details as possible. The patient repeats the treatment repeatedly until the stress is reduced. However, patients undergoing VRE therapy still retell the traumatic experience, but they are witnessing a variety of computer-generated stimuli in a program that allows them to view the experience in a concrete manner. The patient wears a head-mounted display, or video eyeglasses, while either riding or driving a simulated convoy or military vehicle, while the therapist matches the event with the patient's personal narrative of the trauma. As a result, the incorporation of various stimuli during a therapy session can significantly reduce the problem of patients expressing difficulty mentally envisioning the anxiety-provoking scenes VRT can provide stimuli for patients who have difficulty in imagining anxiety-provoking scenes or are too anxious and scared to experience real situations.
According to Van Etten and Taylor (1998), although behavioral therapy through exposure is much more effective over other treatment options for PTSD related symptoms, most participants express difficulty envisioning their traumatic experiences. One can see the rationale behind VRE therapy because there is a considerable difference between a patient repeatedly having to close his eyes to recount and imagine the situation as opposed to retelling the story and having the same type of event occurring through the display of virtual sights and sounds. Prior to the application of VRE therapy, the existing standard of care for the treatment of PTSD was imaginal exposure therapy, which involves repeatedly reliving a traumatic event through memory and imagination through a systematic graded hierarchy. The desired result is a de-conditioning of the learned association of fearful stimuli invoking a fearful or anxiety producing emotional response through the process of habituation and extinction. Although this form of treatment is low-threat, many patients may be unwilling or unsuccessful in the attempt to effectively visualize the traumatic event. In addition, avoidance of the reminders of the traumatic event is often a condition inherent in PTSD.
Research reveals that the engagement of emotion and fear activation play an essential role in exposure therapy; in fact, the lack of emotional engagement in imagination on part of the client may result in treatment failures or adverse treatment outcomes (Jaycox, Foa, & Morral, 1998). Behaviorally, avoidance is what keeps the trauma alive; however, with VRE therapy, it allows the therapist to put the patient back in the moment in a gradual and controlled manner, which facilitates emotional processing and minimizes avoidance. Successful treatment necessitates the emotional processing of the fear structure in order to modify their pathological elements, in such a way that the stimuli no longer invoke fear. VRE therapy diminishes the probability of distraction and avoidance to the feared situation or stimuli. The treatment objective is to help veterans come to terms with what they have experienced in war zones by immersing them in the sights and sounds of those similarly encountered during combat, which includes the visual and audio effects of the gunshots.
VRE therapy can generate stimuli at a greater magnitude than standard in vivo or imaginal exposure techniques. VRE therapy serves a practical purposes as it extends the shared experience between the patient and the therapist within the confines of the office since "it would be impossible to get clinicians on the battlefield with combat PTSD clients, and it is currently impossible to share the clients' imagined scenes" (Rizzo, Rothbaum, & Graap, 2006). The merging of therapy with technology allows the therapist to consistently expose the patient to the traumas, as opposed to merely relying on their imagination. An advantage of VRE includes the ability to administer the therapy within the therapist's office, decreasing the risk of harm or embarrassment for the client, and the ability to control the exposure to the stimuli. The repeated engagement of the fear structure through VRE therapy in a safe, controlled environment enables the patient to virtually re-experience the traumatic events in a controllable manner that allows for habituation and a decrease in anxiety, which thereby, allows the incorporation of new information to occur. The remainder of this paper will discuss the application of VRE therapy to different cases involving combat veterans exhibiting PTSD.
Researchers at Emory University developed the first virtual reality application for the treatment of PTSD to a Vietnam combat veteran. In Rothbaum et al.'s (1999) case study, a 50-year old Caucasian male, had served as a Vietnam helicopter pilot and met the DSM-IV-TR criteria for PTSD, major depressive disorder, and substance abuse 20 years following the Vietnam War. Despite completing treatment at the Atlanta VA Medical Center, he still exhibited the depressive symptoms and suffered from PTSD. During treatment, the patient was exposed to two virtual environments, involving a virtual Huey helicopter flying over Vietnam and a landmass surrounded by jungle.
The treatment was administered in fourteen, 90-minute sessions conducted bi-weekly over 7 weeks. The treatment involved exposing the patient to both audio and visual effects in a virtual jungle. The virtual helicopter included sounds of the rotor, gunfire, bombs, engine sounds, and radio chatter. The visual effects included flashes from the jungle, helicopters flying overhead, landing and take off, fog, as well as the terrain below the helicopter. The audio effects included recordings of gunfire, helicopters, mine explosions, and men yelling orders, such as "Move out! Move out!" All of these effects could be increased in intensity. As the patient is exposed to the visual and audio stimuli, the patient is asked to describe the explicit memories triggered by the computer-generated virtual environment several times in the present tense. This is to induce habituation and decrease anxiety.
Unlike standard exposure therapy, the patient is confronted with the images and scenes being described in his personal narrative of the memory in real-time, as opposed to re-living the experiences mentally. The therapist attempts to match the virtual reality experience as closely as possible to the patient's recounting of the trauma. In addition, the patient is asked to keep his eyes open in order to confront the fearful stimuli. During the process, therapist is able to view the virtual environment that the patient is interacting with on a video monitor. As a result, the therapist is able to communicate with the patient and further continued exposure to the fearful stimuli until anxiety is habituated, so the ultimate goal is to make the trauma become a memory, rather than a flashback or nightmare that controls them. The therapist can manipulate virtual situations to best suit the individual patient during a standard therapy session. By gradually re-introducing the patients to the experiences that triggered the trauma, the memory becomes tolerable.
Results from the VRE therapy indicated that the patient experienced a 34% decrease on clinician-rated PTSD, as well as a 45% decrease on self-rated PTSD. In addition, results of the trial indicated a decrease in his avoidance score and an improvement on all measures of PTSD, as well as maintenance of these gains 6 months after the administration of the exposure therapy (Rothbaum et al., 1999). Furthermore, depression, anger, and substance abuse were not adversely affected. Although the report is quite limited in scope and cannot be generalized across all combat veterans exhibiting PTSD since it is just one subject, the results have implications for future research in the treatment component for combat veterans with PTSD. The study was later followed by an open clinical trial with 16 Vietnam male veterans, which followed the same procedures as the original Virtual Vietnam case. Results from the follow-up study revealed that after 13 VRE therapy sessions, there was a significant reduction in PTSD related symptoms (Rothbaum, Hodges, Ready, Graap, & Alarcon, 2001). Such results suggest that the use of virtual reality, combined with valuable technology, may be a promising treatment approach for veterans with combat-related PTSD.
Virtual Iraq and Afghanistan
The University of Southern California Institute for Creative Technologies (ICT) and Virtually Better, Inc. (VB) also initiated a virtual reality application for the treatment of PTSD in returning Iraq or Afghanistan War military personnel. Virtual Iraq and Afghanistan is currently being implemented in the following locations: Madigan Army Medical Center at Ft. Lewis, the Naval Medical Center in San Diego, Camp Pendleton, Emory University, Weill Medical College of Cornell University, and at 24 other Veterans Affairs military and laboratory sites. Results from the Naval Medical Center in San Diego from a clinical sample trial revealed statically and clinically meaningful reductions in PTSD symptoms, including anxiety and depression. In addition, according to Reger, Gahm, Rizzo, Swanson, and Duma (2009), the patient reports suggested, "They saw improvements in their everyday life situations."
Unlike VRE therapy for Vietnam Veterans, the project takes a few steps forward in realism through the incorporation of olfactory and tactile stimuli into the virtual Iraq and Afghanistan environment. Olfactory stimulation is delivered through a computer device called ES-1 Scent Machine, which utilizes eight scent cartridges, a series of fans, and an air compressor delivering scents to the participants. Olfactory stimuli incorporated in the virtual program include smoke, burning rubber, garbage, body odor, diesel fuel, Iraqi spices, and gunpowder. In addition, Virtual Iraq and Afghanistan incorporates tactile input in the software through the form of vibrations that reverberate on the client's floor platform. Explosions, gunfire, or the movement of a military vehicle over uneven pavement can activate the tactile input.
With similar delivery features as those in Virtual Vietnam, like audio and visual effects, and the simultaneous delivery of olfactory stimuli and tactile stimulation, the result is the creation of a multimodal experience for the participant because it taps into all the sensory modalities. As a result, this enables the participant to become immersed in the virtual environment through the senses. Various scenarios of the landscape exist such as small rural villages, desert bases, desert convoys, city building interiors, and checkpoint patrolling. Overall, the effect is an enhanced sense of presence in the environment. However, the most important feature of the program is the incorporation of a clinical interface that is easily customizable to the needs of the client, as there is such great flexibility in the therapist's ability to monitor and modify client anxiety through the various sensory stimuli.
VRE therapy provides a context by allowing individuals to process their emotions relevant to the trauma in a therapeutic manner, engage in extinction training, and ultimately decrease the symptoms from the conditioned fearful stimuli to the emotional responses (Pitman, Orr, Forgue, de Jong, & Claiborn, 1987). The therapist can achieve this by assisting the patient in modifying the dysfunctional thoughts and beliefs through cognitive restructuring. The current state of VRE therapy necessitates further need of research, even if authors from the Virtual Vietnam study found a reduction of PTSD symptoms and a diminishing of PTSD symptoms in 45% of them (Rothbaum et al., 1999). Virtual Vietnam and Virtual Iraq and Afghanistan are cases that utilize VRE therapy; however, they have obvious limitations.
Although unlike traditional exposure therapy methods, VRE therapy allows the individual to relive the traumatic experience through confrontation in a virtual presence, rather than mere imagination and memory recall, the sense of virtual presence is dependent on what the participant can bring psychologically. VRE therapy requires that the participant give up their sense of physical presence in their current environment in order for virtual presence in their traumas to truly be effective. In other words, participants must immerse themselves onto the virtual world. According to Glantz, Rizzo, and Graap (2003), participants must divide their overall sense of presence in their current real-time world by the virtual environment. Results from previous VRE therapy results reveal that the longer subjects remained in the virtual environment within and between sessions, there was a decrease in the sense of presence between the current environment and the virtual world, even with minimal stimuli (Rizzo, Schultheis, Kerns, & Mateer, 2004).
Thus, how VRE therapy affects treatment outcome primarily depends upon not only the virtual content itself, but it also depends on the degree of the participant's willingness to partake in imaginary presence. Furthermore, the physical features of program, such as color resolution, amount of interactivity between the participant and the program, the degree of realism in the virtual environment and its stimuli, and individual perception of the therapist's ability to match the content with the personal narrative. The aforementioned qualities of the VRE program cannot be ignored because they all contribute to meaningful content and the patient's ability so subjectively confront the trauma. Therefore, how well the content represents the trauma, in regards to emotional symbolism and realism take into account treatment effectiveness. However, VRE therapy should be supplemented with other forms of assistance, including medication and social service.
Although the literature is limited since VRE therapy has recently emerged for the treatment of PTSD, findings from the research has implications for future applications of VRE therapy in the treatment of specific phobias, including fear of flying, fear of public speaking, the fear of being in certain situations, and various other scenarios. In addition, the application of VRE therapy could aid in the assessment combat readiness and stress reduction for soldiers, when the programs are used as combat simulators. Virtual reality systems can help soldiers increase their competency and certainty in the battlefield. Through virtual reality training simulations, soldiers can become aware of dangerous situations.
VRE therapy allows researchers to further understand the role of emotions in training situations or combat situations alike, which has implications for the possible prevention of PTSD symptoms, such as nightmares, insomnia, and flashbacks, after an encounter with a traumatic experience. Most importantly, VRE therapy allows researchers to understand the extent of how combat and war experiences can shape and affect the role of emotions in one's life afterwards.