Prolonged Exposure and Virtual Reality–Enhanced Imaginal Exposure for PTSD following a Terrorist Bulldozer Attack: A Case Study

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  • Prolonged Exposure and Virtual RealityEnhancedImaginal Exposure for PTSD following a Terrorist

    Bulldozer Attack: A Case Study

    Sara A Freedman, Ph.D.,1 Hunter G. Hoffman, Ph.D.,2 Azucena Garcia-Palacios, Ph.D.,3

    Patrice L (Tamar) Weiss, Ph.D.,4 Sara Avitzour, MSW,1 and Naomi Josman, Ph.D.4


    In this case study, virtual reality was used to augment imaginal exposure in a protocol based on prolongedexposure. A 29-year-old male patient developed posttraumatic stress disorder after surviving a deadly terroristbulldozer attack on two civilian buses and several cars in Jerusalem; the traumas witnessed by the survivorincluded a decapitation. The crowded bus in which the patient was riding was pushed over onto its side by theterrorist, injuring, trapping, and terrifying the passengers and causing gasoline to leak. Guided by his therapist,the patient entered an immersive computer-generated virtual world to go back to the scene of the traumaticevent to help him gain access to his memories of the event, process and reduce the intensity of the emotions(fear=anger) associated with his pathological memories, and change unhealthy thought patterns. Traumaticmemories of childhood abuse and traumatic memories of the bulldozer terrorist attack were treated usingimaginal exposure while the patient was in the virtual environment BusWorld. The patient showed largeposttreatment reductions in PTSD symptoms, and his Clinician-Administered PTSD Scale (CAPS) scoresdropped from 79 pretreatment to zero immediately posttreatment, and CAPS was still at zero 6 months later.Although case studies are inconclusive by nature, these encouraging preliminary results suggest that furtherexploration of the use of virtual reality during modified prolonged exposure for PTSD is warranted. As terroristattacks increase in frequency and severity worldwide, research is needed on how to minimize the psychologicalconsequences of terrorism.


    Asubset of people who experience a terrifying and po-tentially deadly physical or emotional incident developchronic psychological problems such as posttraumatic stressdisorder (PTSD). The incidence of developing PTSD followingdirect exposure to a terrorist attack is as high as 37.8%.1 Peoplewith PTSD commonly have persistent thoughts, memories, ornightmares about the traumatic event; have trouble sleeping;avoid thinking about the traumatic event; feel emotionallynumb; and show social avoidance. Other common symptomsinclude recurring flashbacks, irritability, anger, rage, and hy-pervigilance. PTSD sufferers often systematically avoid mem-ories and emotions associated with the traumatic event. Foaand Kozak2 theorize that avoidance perpetuates pathologicalmemories of traumatic events and interferes with recovery.

    When used to treat PTSD, the core components of exposuretherapy include having participants repeatedly self-generate,visualize, and describe their recollection of the traumaticevent (imaginal exposure) and gradually exposing them re-peatedly to fear-evoking, real-world situations or objects thatremind them of their traumatic event (in vivo exposure).3

    According to Foa and Kozak,2 the most effective exposuretherapy involves eliciting a fear response as patients ac-cess their memory of the traumatic event. During therapy,while their memory of the traumatic event is activated andthey are showing a fear response, patients process theiremotions associated with the traumatic memory (e.g., viahabituation). While their memory of the traumatic event isaccessed, information incompatible with some of the patho-logical elements of memory is introduced. For example, in-stead of the erroneous belief that avoiding any thoughts

    1Department of Psychiatry, Hadassah University Hospital, Jerusalem, Israel.2HITLab, Mechanical Engineering, University of Washington, Seattle, Washington.3Department of Psychology, Jaume I University, Castellon, Spain.4Department of Occupational Therapy, University of Haifa, Mount Carmel, Haifa, Israel.

    CYBERPSYCHOLOGY, BEHAVIOR, AND SOCIAL NETWORKINGVolume 13, Number 1, 2010 Mary Ann Liebert, Inc.DOI: 10.1089=cyber.2009.0271


  • associated with the traumatic event is their best coping strat-egy, patients may realize during therapy that gradually ap-proaching and remembering the traumatic event will reducetheir suffering in the long run. During therapy, a healthiermemory is formed containing new elements. Patients developmore accurate metamemorial assumptions and retain fewerpathological beliefs. Exposure therapy is the most empiri-cally supported intervention for PTSD4 and has a high treat-ment success rate for patients who complete treatment.Unfortunately, most people who have PTSD never seektreatment, and most people with PTSD who seek treatmentnever receive cognitive behavior therapy (CBT) involvingexposure (e.g., prolonged exposure [PE]). Although large-scale efforts to increase dissemination are underway, CBTcombined with exposure is not widely used by clinicians in thecommunity who treat patients with PTSD.5 Several differentexposure therapy protocols for treating PTSD have been de-veloped and studied. In addition to the goal of improvingoutcome of completers, increasing patient and clinician ac-ceptance and reducing treatment dropouts are importantareas for future improvement.

    People with PTSD fastidiously avoid thinking about theirtraumatic event. Getting them to imagine=self-generateimages of their traumatic experience during therapy can bedifficult.2 Patients often have exaggerated worries about whatis going to happen if they allow themselves to access theirtraumatic memory (e.g., they will go crazy or have a heartattack). For some patients, pathological memories may beunusually difficult to access using imaginal exposure, limit-ing emotional processing.2 According to Foa and Kozak,2

    situations that enhance fear evocation and habitation duringtherapy are expected to improve treatment outcome.

    Virtual reality (VR) computer-generated simulations oftraumatic events have been proposed as a means of facili-tating a patients ability to visualize and remember a fear-provoking traumatic event in a gradual, controlled fashion.6,8

    Instead of patients having to use great effort to self-generateimages that help them gain access to their memories oftraumatic events, the computer generates the images forthem. Guided by their therapist, patients enter an immersivecomputer-generated virtual world that helps take them backto the scene of the traumatic event. With VR, patients expe-rience gradually more realistic depictions of the terrorist at-tack they witnessed=experienced, to help them gain access totheir memories of the event, process and reduce the intensityof the emotions (fear=anger=guilt) associated with their path-ological memories (e.g., via habituation), and change un-healthy thought patterns. Graded exposure helps patientsbecome more comfortable thinking about what happenedwith much less anxiety and less avoidant of remembering thetraumatic events.

    VR therapy for PTSD was first used in a case series byRothbaum et al.7 to treat combat veterans. In the first studyusing VR to treat civilian PTSD, Difede and Hoffman6 de-veloped a virtual environment that involves a graded im-mersive simulation the September 11, 2001, attack at theWorld Trade Center in Manhattan. In the first controlledstudy on VR exposure therapy for PTSD,8 nine out of the 10VR exposure therapy patients showed a reduction in PTSDsymptoms, seven patients no longer had PTSD after VR ex-posure therapy, and five who had previously failed to im-prove with traditional therapy showed 25% to 50% or more

    reductions in PTSD symptoms after completing therapy.8

    These gains were maintained at 6-month follow-up. In con-trast, all waiting-list control patients still had clinical PTSD atthe end of the study. Further research on VR exposure ther-apy for PTSD is warranted by these encouraging preliminaryresults, and there are a growing number of patients needingtreatment for PTSD. For example, tens of thousands of U.S.soldiers are returning from Iraq and Afghanistan with PTSD.9

    As terrorist attacks increase in frequency and severity world-wide, research is needed on how to minimize the psycho-logical consequences of terrorism.4

    Palestinians and Israelis have both been victims of trau-matic events stemming from their violent conflict. Israelicivilians have been targeted in a number of Palestinian ter-rorist attacks. For example, in 2008, in downtown Jerusalem,a Palestinian construction worker driving a bulldozer at-tacked a woman and infant in a car, ramming the plow of hisbulldozer into the womans windshield, decapitating thefemale driver with his plow.10 He subsequently used hisbulldozer to lift two public transit buses loaded with civilianpassengers onto their sides, trapping the passengers inside(see Fig. 1), and went on to crush several more cars. Severalcivilians were killed, and their mutilated bodies had to beextricated from cars crushed by the bulldozer. In addition tothe fatalities, several people were injured in the attack. Anumber of survivors of that attack subsequently developedPTSD. The patient in the present case study was a passengeron one of the buses turned over in the attack. He was in gravepersonal danger and helped other passengers off the busbefore escaping himself.

    This case report presents the first results of a treatmentbased on Foas PE protocol11 but using VR to augment theimaginal exposure components during treatment of PTSD ina civilian survivor of the 2008 bulldozer attack.



    At pretreatment assessment, the patient was a 29-year-oldmiddle-class married male Israeli citizen. He had recentlysurvived the July 2008 terrorist bulldozer attack in Jerusalemand entered treatment approximately 1 month after the at-tack. He is college educated, has been employed full timesince the traumatic event, and has had no prior treatment forPTSD. His reexperiencing symptoms included nightmaresand intrusive images of the terror attack as well as nightmaresand intrusive thoughts of previous traumas. His flashbacks ofthe bulldozer attack were very vivid, including smell. Heshowed significant physiological reactivity (fight-or-flightresponse) with these intrusions. His avoidances includedtrying not to think or talk about the event, avoiding travelingon buses, avoiding the place of the attack, and avoidingpeople of Arab descent. He reported significant sleep dis-turbance, anger outbursts, difficulty concentrating, and anexaggerated startle response. Pretreatment, the patient ful-filled criteria for PTSD related to the terrorist attack as well asa major depressive disorder. According to the pretreatmentassessment, carried out with the Structured Clinical Interviewfor DSM-IV (SCID) and Clinician-Administered PTSD Scale(CAPS), the patients PTSD symptoms and depression hadbegun subsequent to the attack and included suicidal idea-tion, although with no concrete plans to commit suicide.


  • Although the patient showed no psychiatric diagnoses priorto the traumatic event, he did have pretrauma subclinicalobsessive compulsive disorder (OCD), which had consider-ably worsened since the attack and now fulfilled criteria forOCD at pretreatment assessment.


    During the VR exposure sessions, the participant wore ahead-mounted display that included separate display screensfor each eye and stereo earphones. The participant was pre-sented with a computer-generated view of Virtual IsraelBusWorld environment.12 He was able to look around thevirtual world using a mouse. Our simulation of a terrorist busbombing attack allows graded exposure wherein a therapistis able to control the severity of the scenario by pressing twofunction keys and by simply asking the participant to visu-alize various subsets of the attack while in VR. In the presentstudy, the virtual environment depicted two increasingly

    distressing levels of exposure. Level 1 shows the street scenefrom an urban Israeli sidewalk, near a cafe, across the streetfrom a bus stop. At level 2, a bus appears, approaches, andstops at the bus stop. Higher levels of BusWorld (levels 3through 12), depicting suicide bus bombings of graduallyincreasing levels of severity (see Josman et al.12 for details)were available to the therapist but not needed with thepresent patient.

    BusWorld was designed by our team with input created the BusWorldVR software for our team, incorporating sound effects gen-erously provided by Navy Commander Russell Shilling.BusWorld was originally designed to treat PTSD patientswho had witnessed a terrorist suicide bus bomb explosion.12


    All treatments and assessments occurred in the Depart-ment of Psychiatry, Hadassah University Hospital, Jerusalem,

    FIG. 1. Bulldozer used in a terrorist attack on civilians in Jerusalem (A: photo by Gil Yochanan, and thepatients attacked bus (B: photo by Moti Boksin,, Zaka Organization; both images used withpermission).


  • Israel, with Institutional Review Board approval. At Ha-dassah Hospital, all patients who seek medical treatment atthe emergency room following a large-scale terrorist attackare followed up afterwards by a psychologist. This patientreceived a telephone interview 4 days after the attack. Duringthe interview, he described high levels of PTSD and depres-sive symptoms. He was invited to attend a clinical assess-ment, which took place 1 month posttrauma. At thisassessment, standardized clinical interviews were carried out.The patient was asked to join the study, he signed informedconsent, and began treatment 6 weeks after the terrorist at-tack. The clinical assessments carried out pre- and posttreat-ment were conducted by an independent assessor, a trainedtherapist who was blind to what treatment the patient re-ceived (i.e., was not aware that the patients treatment in-volved VR). The patient was assessed using two standardizedclinical interviews: the Clinician-Administered PTSD Scale(CAPS)13 and the Structured Clinical Interview for DSM-IV(SCID-I).14 The interviews and questionnaires were repeatedat the end of treatment. In addition, the patient completedseveral self-report questionnaires. The Beck Depression In-ventory (BDI),15 Posttraumatic Symptoms Scale (PSI),15

    Posttraumatic Cognitions Inventory (PTCI),17 and BriefSymptom Inventory (BSI)18 were filled out biweekly duringthe treatment.


    Because three of the imaginal exposure sessions took placewhile the participant was in VR, the treatment was not PE,which has a very strict definition. The treatment is based onPE,11 and treatment was carried out and supervised by ther-apists who have extensive knowledge and training in PE. Thetreatment was delivered during 10 individual sessions of 90minutes each conducted approximately once weekly over a12-week period. The initial session consisted of psychologicaleducation rega...


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