7
Virtual Reality Exposure Therapy for World Trade Center Post-traumatic Stress Disorder: A Case Report JOANN DIFEDE, Ph.D., 1,2 and HUNTER G. HOFFMAN Ph.D. 3,4 ABSTRACT Done properly by experienced therapists, re-exposure to memories of traumatic events via imaginal exposure therapy can lead to a reduction of Post-traumatic Stress Disorder (PTSD) symptoms. Exposure helps the patient process and habituate to memories and strong emotions associated with the traumatic event: memories and emotions they have been carefully avoid- ing. But many patients are unwilling or unable to self-generate and re-experience painful emotional images. The present case study describes the treatment of a survivor of the World Trade Center (WTC) attack of 9-11-01 who had developed acute PTSD. After she failed to im- prove with traditional imaginal exposure therapy, we sought to increase emotional engage- ment and treatment success using virtual reality (VR) exposure therapy. Over the course of six 1-h VR exposure therapy sessions, we gradually and systematically exposed the PTSD patient to virtual planes flying over the World Trade Center, jets crashing into the World Trade Center with animated explosions and sound effects, virtual people jumping to their deaths from the burning buildings, towers collapsing, and dust clouds. VR graded exposure therapy was suc- cessful for reducing acute PTSD symptoms. Depression and PTSD symptoms as measured by the Beck Depression Inventory and the Clinician Administered PTSD Scale indicated a large (83%) reduction in depression, and large (90%) reduction in PTSD symptoms after completing VR exposure therapy. Although case reports are scientifically inconclusive by nature, these strong preliminary results suggest that VR exposure therapy is a promising new medium for treating acute PTSD. This study may be examined in more detail at www.vrpain.com. 529 CYBERPSYCHOLOGY & BEHAVIOR Volume 5, Number 6, 2002 © Mary Ann Liebert, Inc. INTRODUCTION T HE CURRENT STANDARD OF CARE FOR Post- traumatic Stress Disorder (PTSD) is imagi- nal exposure therapy. The efficacy of imaginal exposure has been established in multiple studies with diverse trauma populations. 1,2 However, imaginal exposure presents an un- solvable dilemma for some patients. Effective imaginal exposure requires patients to retell their trauma in the present tense to their thera- pist, over and over again. Avoidance of re- minders of the trauma is inherent in PTSD, and is a defining symptoms of the disorder. Some patients refuse to engage in the treatment, and others, though they express willingness, are 1 Weill Medical College of Cornell University, New York, New York. 2 The New York Presbyterian Hospital, New York, New York. 3 Human Interface Technology Laboratory, University of Washington, Seattle, Washington. 4 Department of Psychology, University of Washington, Seattle, Washington.

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Page 1: Virtual Reality Exposure Therapy for World Trade Center Post-traumatic Stress Disorder: A Case Report

Virtual Reality Exposure Therapy for World Trade Center Post-traumatic Stress Disorder:

A Case Report

JOANN DIFEDE, Ph.D.,1,2 and HUNTER G. HOFFMAN Ph.D.3,4

ABSTRACT

Done properly by experienced therapists, re-exposure to memories of traumatic events viaimaginal exposure therapy can lead to a reduction of Post-traumatic Stress Disorder (PTSD)symptoms. Exposure helps the patient process and habituate to memories and strong emotionsassociated with the traumatic event: memories and emotions they have been carefully avoid-ing. But many patients are unwilling or unable to self-generate and re-experience painfulemotional images. The present case study describes the treatment of a survivor of the WorldTrade Center (WTC) attack of 9-11-01 who had developed acute PTSD. After she failed to im-prove with traditional imaginal exposure therapy, we sought to increase emotional engage-ment and treatment success using virtual reality (VR) exposure therapy. Over the course of six1-h VR exposure therapy sessions, we gradually and systematically exposed the PTSD patientto virtual planes flying over the World Trade Center, jets crashing into the World Trade Centerwith animated explosions and sound effects, virtual people jumping to their deaths from theburning buildings, towers collapsing, and dust clouds. VR graded exposure therapy was suc-cessful for reducing acute PTSD symptoms. Depression and PTSD symptoms as measured bythe Beck Depression Inventory and the Clinician Administered PTSD Scale indicated a large(83%) reduction in depression, and large (90%) reduction in PTSD symptoms after completingVR exposure therapy. Although case reports are scientifically inconclusive by nature, thesestrong preliminary results suggest that VR exposure therapy is a promising new medium fortreating acute PTSD. This study may be examined in more detail at www.vrpain.com.

529

CYBERPSYCHOLOGY & BEHAVIOR

Volume 5, Number 6, 2002© Mary Ann Liebert, Inc.

INTRODUCTION

THE CURRENT STANDARD OF CARE FOR Post-traumatic Stress Disorder (PTSD) is imagi-

nal exposure therapy. The efficacy of imaginalexposure has been established in multiplestudies with diverse trauma populations.1,2

However, imaginal exposure presents an un-

solvable dilemma for some patients. Effectiveimaginal exposure requires patients to retelltheir trauma in the present tense to their thera-pist, over and over again. Avoidance of re-minders of the trauma is inherent in PTSD, andis a defining symptoms of the disorder. Somepatients refuse to engage in the treatment, andothers, though they express willingness, are

1Weill Medical College of Cornell University, New York, New York.2The New York Presbyterian Hospital, New York, New York.3Human Interface Technology Laboratory, University of Washington, Seattle, Washington.4Department of Psychology, University of Washington, Seattle, Washington.

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unable to engage their emotions or senses.During imaginal therapy, such patients retella flat emotionless tale reflecting their numb-ness, and fail to improve. The few studiesthat have addressed the question of treat-ment failures have concluded that failure toengage emotionally predicts a poor treat-ment outcome.3

The present case study describes the treat-ment of a survivor of the World Trade Center(WTC) attack of September 11th, 2001 who de-veloped acute PTSD. After failing to makeprogress using traditional imaginal exposuretherapy, this patient was offered the opportu-nity to try virtual reality (VR) exposure. Thepresent study explored whether immersive VRcould be used to facilitate the patient’s emo-tional engagement and thereby improve theefficacy of exposure therapy for acute PTSD.

Until the recent introduction of VR-basedtherapies, imaginal exposure therapies reliedsolely on the imaginative and memorial capac-ities of individual patients. Virtual reality af-fords opportunities not only to capitalize onpatient’s imagery capacities,4 but also to aug-ment them with visual, auditory, and evenhaptic computer-generated experiences.5–7 Forpatients who are reluctant to engage in recol-lections of feared memories, the sensory-richvirtual world creates an evocative therapeuticenvironment which may encourage the pa-tient’s emotional engagement. Because the vir-tual environment can be encountered at thepatient’s own pace, a firm distinction can becreated between remembering (and staying incontrol) and reliving8 (becoming overwhelmedby the re-experience). Additionally, VR tech-nology allows for graded exposure to increas-ingly feared virtual environments/objects/events that can be carefully monitored and tai-lored to the individual patient.9 As a result, VRtherapy experiences may increase a patient’sfeelings of self-efficacy and of being an activeagent of their own experience.

Research has shown that VR exposure ther-apy is effective for the treatment of anxietydisorders other than PTSD, such as specificphobias. VR exposure has been effective forfear of heights,10,11 fear of flying,12–14 claustro-phobia,15,16 and spider phobia.17,18 As withPTSD, patients with specific phobias avoid the

feared stimulus, but must confront it to getwell. Research suggests that those sufferingfrom phobias may be more likely to seek andcomplete therapy with VR exposure than withtraditional exposure.19 The VR world oftendoes not include the same risks as returning tothe feared environment and patient’s can feelsupported in knowing that the therapist view-ing the virtual environment is sharing in theirexperiences.

VR-based therapy for PTSD was introducedby Rothbaum and colleagues.20,21 Based ontheories of Foa and colleagues,8,22 Rothbaumand colleagues proposed that the illusion ofpresence in the virtual world facilitates emo-tional processing of memories associated withthe traumatic event. Additionally, they haveshown that virtual reality exposure therapycan reduce symptoms of chronic PTSD in Viet-nam Veterans.20,21 The present study is the firstto explore whether VR exposure therapy is ef-fective for treating acute PTSD (within a fewmonths after the traumatic event).

MATERIALS AND METHODS

Assessment method

Our patient was assessed with standardizedclinical and self-report instruments. PTSD wasassessed with the Clinician AdministeredPTSD scale (CAPS), psychiatric history was as-sessed with the Structured Clinical Interviewfor the DSM-IV,23 and trauma history wasassessed with a structured trauma historychecklist. Standardized self-report measuresincluded the Beck Depression Inventory andthe Post-traumatic Diagnostic Scale. A baselineclinical assessment was conducted one weekprior to the initiation of VR treatment, and in-cluded the standardized clinical and self-report measures. The self-report measureswere also administered prior to each VR treat-ment session. Assessments were conductedbefore the patient began VR therapy, and aftercompleting the final VR treatment session, byan independent assessor blind to the treatmentcondition. During treatment, the patient ratedher distress several times a session, using theSubjective Units of Distress Scales.24

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Three months post-trauma

Our patient was a 26-year-old single AfricanAmerican female presented for evaluation ap-proximately four months after the attack onthe WTC. At the time of the attack, she was anexecutive for a large financial institution lo-cated near the WTC. Prior to September 11th,she had functioned well in a very competitiveindustry and was on the “fast track.” She de-scribed herself as having bright prospects andthe ambition to match.

The patient was across the street from theNorth tower when the first plane hit. Duringher evaluation she described with little emotionthe sequence of events that she experiencedSeptember 11th. She spoke in a monotone voice,and denied feeling any terror when giving herdescription.

The patient was diagnosed with PTSD and aco-morbid major depression according toDSM-IV criteria. She did not meet criteria forany other Axis I or II disorder. She had notrauma history. She reported moderate to se-vere symptoms in each of the three DSM-IVcluster areas for PTSD. Her re-experiencingsymptoms included frequent unbidden intru-sive imagery of the plane striking the tower,and the building collapsing, being distressedwhen confronted with reminders, and occa-sional flashbacks. The patient’s avoidantsymptoms were extensive, and includedavoiding thoughts of the attack, avoiding re-minders of the attack (e.g., refusal to watch TVnews or read newspapers) and avoiding situa-tions where she perceived herself to be espe-cially vulnerable (e.g., she would not stay inher boyfriend’s apartment because it was on a

high floor of a tall tower). Although she wasraised in a close extended family, she de-scribed feeling distant, and cut-off from herfamily and friends after September 11th. Hersymptoms of hyperarousal included difficultyfalling asleep and staying asleep, difficultyconcentrating, an exaggerated startle responseand intense anger. Her hypervigilance ex-tended to sleeping with the lights on and keep-ing a pair of eyeglasses near the door. Shereported being very irritable and angry withthose closest to her. She repeatedly lost hertemper and yelled at her mother and others inher family. She had “no patience” for them.She noted that this was unlike her. Indeed itwas her mother who initially called the firstauthor to ask for help, noting that she wasvery worried about her daughter who “wasnot herself, and was unusually irritable.”

Treatment

Before beginning VR therapy, the patienthad been treated with imaginal exposure ther-apy without success. Attempts to engage herin imaginal exposure therapy were made infour successive unsuccessful sessions beforeVR treatment was initiated. There was nochange in the patient’s symptoms of PTSD orMajor Depression between the time of theinitial evaluation and initiation of the VR ex-posure therapy (Table 1, baseline vs. VR ses-sion 1). Though she appreciated the rationalefor the treatment, repeated attempts continuedto yield a flat emotionless tale. The patientgave Subjective Units of Distress ratings ofzero, reflecting her inability to engage emo-tionally. In a rather irritable voice, she would

VR EXPOSURE THERAPY FOR WORLD TRADE CENTER PTSD 531

TABLE 1. SELF-REPORT SCORES OF PTSD AND DEPRESSION

Depression PTSD (PDS) Reexperience Avoidance Arousal(BDI) total score symptoms symptoms symptoms

Baseline 37.00 37.00 9.00 16.00 12.00VR Session 1 30.00 40.00 13.00 14.00 13.00

(week 5)Completion of 5.00 4.00 1.00 0.00 3.00

Treatment(week 14)

Note that re-experiencing symptoms + avoidance symtoms + arousal symptoms =PTSD total score.

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give the therapist a vexed look and say, “Idon’t understand why I should do this. I amfine.” Though saying that she was fine, infollow-up discussion with her therapist (J.D.),she would acknowledge that there was some-thing wrong because she was aware of, anddistressed by, her irritability. Thus, she agreedto try the VR therapy.

For VR exposure therapy, the patient worea virtual reality helmet that positioned twogoggle-sized miniature computer monitorscreens close to the patient’s eyes. Positiontracking devices kept the computer informedof changes in the patient’s head location. Thescenery in VR changed as the patient movedher head orientation (e.g., virtual objects infront of the patient in VR got closer as the pa-tient, wearing the VR helmet, leaned forwardin the real world). The essence of immersivevirtual reality is the illusion it gives patientsthat they are inside the computer-generatedenvironment—as if they are “there” in the vir-tual world. In the present study, the place thepatient visited was lower Manhattan, and theevent she re-experienced was the September11th attack on the WTC.

Equipment

A Dell (www.dell.com) 530 workstationwith dual 2-gig CPUs, 2 gigs of RAM, a Wild-cat 5110 video card, Windows 2000 operatingsystem, and MultiGen-Paradigm Inc Vega VRsoftware (www.multigen.com) was coupledwith a 1,024 2 768 resolution VR helmet, with40 degrees horizontal field of view(www.keo.com/proviewxl3550.htm). A Polhe-musTM Fastrak position tracking system wasused to measure the position of the user’shead (www.polhemus.com).

The virtual World Trade Center world

After putting on the head gear, initially thepatient saw the twin WTC towers from a dis-tance, with no sound effects, with a sunny bluesky, as it appeared the morning of September11, 2001. The virtual world was programmedsuch that the therapist was able to controlwhat the patient experienced in VR by touch-ing pre-programmed keys on the keyboard.

The therapist was able to view what the pa-tient was experiencing simultaneously on thecomputer screen. The following is a list of thesequences that the patient viewed:

a. A jet flies over the WTC towers, but doesn’tcrash, normal New York city street sounds.

b. Then a jet flies over, hits building, but noexplosion

c. Then a jet flies over, crashes with explosion,but no sound effects

d. Then a jet flies over, crashes with explosion,and explosion sound effects

e. Burning and smoking building (with holewhere jet crashed), no screaming

f. Burning and smoking building (with holewhere jet crashed) and screaming

g. Burning and smoking building (with holewhere jet crashed), screaming, and peoplejumping

h. Second jet crashes into second tower withexplosion and sound effects

i. Second tower collapses with dust cloudj. First tower collapses with dust cloud

k. The full sequence

Procedure

Time in VR ranged from 45 to 60 min persession. The pace was patient-driven. Each se-quence in the VR menu was repeated until theSubjective Units of Distress level decreased byat least 50%. Each sequence was repeated anumber of times before habituation occurred.The next sequence was not approached with-out the patient’s verbal assent. This procedurewas designed to evoke a level of response thatcreated discomfort, but was tolerable. Gradu-ally, as the patient habituated to her experi-ence, she was able to approach sequences thatmore nearly approximated the traumatic event(Fig. 1). After two VR exposure therapy ses-sions, the patient was able to experience themost realistic version of the WTC virtualworld, sequence K (the full sequence).

Course of treatment

While it had not been possible to engage thepatient in imaginal exposure, it was apparentfrom the very first moments of VR exposure

532 DIFEDE AND HOFFMAN

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therapy that she was able to engage emotion-ally in the virtual WTC world. This was evi-dent in her verbal report, her behavior, notablephysical signs of emotional arousal, and in herSubjective Units of Distress scores. She ap-proached the first sequence with nervous, butdetermined, anticipation. As she viewed thefirst image of the twin towers through the VRhelmet, she began to cry for the first time, say-ing that she “never thought she’d be able tolook at them again”. She then began to recountan emotional tale of the harrowing events ofthat day, spontaneously recalling memoriesthat had been previously inaccessible. The or-deal began September 11th when she stoppedat a drug store across from her office, on theway to work that morning. She witnessed thesecond plane hit the South Tower while shewas in a crowd of people all of whom werestaring in disbelief. Then it seemed that every-one around her was trying to escape, whichwas terrifying. For the first time since the or-deal began she remembered believing that shewould die. She noted that as she tried to run,

there was a crush of bodies trying to escape,people began to fall on one another, and shestruggled to free herself from beneath severalother people. As she fled, a woman cried outfor help. Our patient recalled meeting thewoman’s eyes, and thinking that if shestopped to help, that she herself would die,too. She looked down to see that the women’slegs had been severed, and she was bleedingto death. Our patient recalled looking in thewoman’s eyes and telling the woman that shecouldn’t stop. Debris was falling all aroundthem bringing along with it the possibility of afatal collision. She recalled running and run-ning through the hazy smoke. Eventually,when she was a few miles away, clear of thesmoke and falling debris, she recalled notingthat people were looking at her oddly. Shestopped in a deli, where people looked calmand were going about their daily routine, andshe screamed “don’t you know what’s hap-pening?” A woman came over to her to helpher. Our patient had no shoes on, no money,and her feet were bleeding. The woman took

VR EXPOSURE THERAPY FOR WORLD TRADE CENTER PTSD 533

FIG. 1. Event 1: (a) A jet flies over the WTC towers, but doesn’t crash, normal NY city street sounds, (b) Then a jetflies over, hits building, but no explosion, (c) Then a jet flies over, crashes with explosion but no sound effects, and (d)Then a jet flies over, crashes with explosion and explosion sound effects. Event 2: (e) Burning smoking building (withhole where jet crashed), no screaming, (f) Burning smoking building (with hole where jet crashed) and screaming, and(g) Burning smoking building (with hole where jet crashed), screaming and people jumping. Event 3: (h) Second jetcrashes into second tower with explosion and sound effects, (i) Second tower collapses with dust cloud, (j) First towercollapses with dust cloud, and (k) The full sequence.

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her to buy a pair of shoes, and gave her carfarehome. Our patient described the relief that shefelt when her boyfriend met her in midtownManhattan to escort her home.

RESULTS

Six VR exposure sessions were conducted.Figure 1 shows the decrease in the patientsSubjective Units of Distress rating over timefor each VR event. After completion of VRtreatment, our patient no longer met criteriafor PTSD, Major Depression, or any other psy-chiatric disorder upon examination by anindependent assessor. This finding was consis-tent with her verbal report and with the im-provement documented on the standardizedself-report measures of PTSD and Major De-pression (Table 1).

DISCUSSION

VR graded exposure therapy was successfulfor reducing acute PTSD symptoms, providingconverging evidence for a growing literatureshowing the effectiveness of VR as a newmedium for exposure therapy. While in the vir-tual WTC world, the patient relived September11th, retrieving and modifying memories shehad already stored. VR exposure therapy isthought to work by modifying the patient’smemory20. After treatment, the patient could re-member what happened to her on September11th with much greater detail, without the samedegree of associated terror. And doing so nolonger elicited PTSD symptoms anymore. VRexposure therapy has the advantage of allow-ing PTSD patients to virtually re-experience theevents of September 11th in a controllable man-ner that allows for habituation. The patient ap-peared to become immersed in the virtualenvironment, and she claimed that going intoVR helped her improve.

In the treatment of PTSD, VR technologiescan offer patients who are unable to otherwiserecount their experiences an external setting inwhich to encounter and master their trauma.The multiplicity of sensory cues that VR af-fords also may provide a greater possibility of

generating patient involvement and a sense ofpresence that can facilitate processing of thetraumatic experience. VR environments can bemanipulated above and beyond the con-straints of the everyday world, thus creatingnew possibilities for therapeutic action.25

The substantial limitations of case studiesare well known.26 Although case studies are agood vehicle for presenting innovative tech-niques, more convincing evidence for effective-ness will require larger, more generalizable,controlled studies. Because of VR’s potential,and the need for new techniques for treatingacute and chronic PTSD, additional research onthe potential value of VR exposure therapy fortreating PTSD is warranted.

ACKNOWLEDGMENTS

This research was funded by a NIMH RapidAssessment Post Impact of Disaster (RAPID)grant to J.D. Pfizer Pharmaceuticals donatedthe high quality VR helmet, head positiontracking system, and other equipment to J.D.for this project. Dell Computers donated thehigh-performance PC computer. WTC worldsoftware was created with funding to DavePatterson from the Paul Allen Foundation forMedical Research and NIH grant GM42725–07.Creation of WTC world involved MultiGen-paradigm VEGA programming by HowardAbrams, custom 3-D models, and animationsby cyberartist Duff Hendrickson, and use of a3-D model of Manhattan donated by www.3dcafe.com, and Digimation. We would alsolike to acknowledge the encouragement andeditorial advice of Ian Alger, M.D.

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Address reprint requests to:JoAnn Difede, Ph.D.

Helmsley Medical Tower1320 York Ave., Ste. 610

New York, NY 10021

E-mail: [email protected]

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