Table 2.

Treatment materials and procedures in the VR and in vivo exposure conditions.

		Exposure Treatment
References	Exposure strategy (VR and in vivo condition)	Type of HMD with image resolution and field of view	Movement mode in VR and devices for tactile and haptic stimulation	VR environments	In vivo environments	Additional interventions (VR and in vivo condition)
Rothbaum et al., 2000	Gradual; encouraging comments by therapist	VR6: 640 × 480/60°	Thunderseata	Window seat inside the passenger compartment of a commercial airplane with empty seats; takeoffs and landings; flying in calm and stormy weather	Airport: ticketing, trains, parked planes, waiting area; sitting on stationary plane (+ imaginal exposure of take-offs, cruising, landing, etc. on stationary planec)	Treatment planning and explaining the rationale to the patients, anxiety management techniques (breathing retraining, cognitive restructuring, thought stopping, in case of panic attacks: hyperventilation exposure)
Emmelkamp et al., 2002	Gradual; habituation rationale; verbal guidance and encouragement by therapist	Cybermind Visette Pro: 640 × 480/71.5°	Walk around freely on 1 m2; railing to hold on	Mall with four floors with escalators and balustrades, fire escape (height: ~50 feet), roof garden at top of building (height: ~65 feet)	Real locations corresponding to VR environments	Intake session
Rothbaum et al., 2006	Gradual	VFX3D: 640 × 480/35°	Seat with seatbelt and bass speaker underneath	Window seat inside the passenger compartment of a commercial airplane; start of engines, announcements of pilot and attendants, taking the plane to the runway, take-off, flying in bad and good weather, landing	Airport: ticketing, trains, waiting area; coordination center tower: viewing planes, speaking with knowledgeable airport personnel; sitting on stationary plane (+ imaginal exposure of take-offs, cruising, landing, etc. on stationary planec)	Treatment planning, anxiety management techniques (breathing retraining, cognitive restructuring, thought stopping, interoceptive exposure)
Michaliszyn et al., 2010	Gradual	I-glasses PC/SVGA A502085® (i-O display systems): 800 × 600/26°	Handheld wireless gyration mouse	Three levels of animated spiders of different shapes and sizes; top item: large black-widow spider	Two types of spiders; top-item: manipulate them in the hand	Psychoeducation, cognitive restructuring, relapse prevention
Anderson et al., 2013	Gradual; habituation rational	VFX headset: 640 × 480/35°	N/A	Virtual conference room (about five audience members), virtual classroom (35 audience members), virtual auditorium (100 audience members); different audience reactions (interested, bored, supportive, hostile, distracted, etc.); audience members posing standardized or individualized questions	Group therapy with up to five participants, videotaped speech in front of the other group members, individualized positive feedback from other group members	Psychoeducation, realistic goal setting for social situations through techniques like cognitive preparation, challenging of cost and probability biases, relapse prevention, homework (daily mirror task, daily record of social situations, identification of cognitive bias)
Kampmann et al., 2016	Gradual; until anxiety decreased; communication with therapist in next room via intercom	nVisor SX: 1,280 × 1,024/60°	N/A	Giving a talk in front of an audience followed by questions, talking to a stranger, buying and returning clothes, attending a job interview, being interviewed by journalists, dining in a restaurant with a friend, having a blind date; semi-structured dialogues with different dialogue-styles and content (friendly vs. unfriendly; personal relevance), different number, gender and gestures of avatars	Participants' individual social situations which were translated to exposure exercises (e.g., in supermarkets, subway stations, cafés, etc.); or exposure in personal environment of the participants with contact to therapist via the telephone before and after the exposure	Therapy rationale and anxiety hierarchy, relapse prevention, evaluation of the therapy
Bouchard et al., 2016	Focus of the exposure: develop new, nonthreatening and adaptive interpretations; habituation not required; active modeling from the therapist in early sessions	eMagin z800: 800 × 600/40°	Wireless computer mouse	Speaking in front of audience in a meeting room, having a job interview, introducing oneself and having a talk with supposed relatives in an apartment, acting under the scrutiny of strangers on a coffee shop patio, facing criticism or insistence (meeting unfriendly neighbors, refusing to buy goods from a persistent seller at a store); preformatted answers triggered by the therapists	Role-playing and guided exposure inside or outside the therapist's office (e. g. asking for the time in a coffee shop, asking strangers on a date, giving an awkward impromptu speech to an audience of staff members, making improper requests in boutiques and stores); audience constituted by laboratory members	Developing a personal case conceptualization model, symptoms and avoidance/safety behavior, cognitive restructuring, relapse prevention
Botella et al., 2007	Gradual	V6: 640 × 480/60°	Mouse	Training room, house, subway, bus, shopping mall, tunnel; simulation of bodily sensations (palpitations and breathing difficulties with three levels of intensity from mild to accelerated, visual effects like tunnel vision, blurred vision, double vision); different modulations: number of people present, length of the trips, difficulties like problem with the credit card at the shopping mall or the elevator suddenly stopped between two floors etc.	in vivo exposure	Psychoeducation, cognitive restructuring and breathing training, interoceptive exposure, recording of panic symptoms, relapse prevention
Meyerbroeker et al., 2013	Gradual manipulation of crowd density in situations	nVisor SX: 1,280 × 1,024/60° (or CAVE with projection on three walls and floorb)	N/A	Supermarket, subway, Italian restaurant with bar annex, town center, large open square, marketplace with market stalls, public building with large open spaces and different floors with café on the ground floor; crowd density could be manipulated	Supermarket, shopping malls, marketplaces, streets and public transportation (e.g., subway)	Psychoeducation, cognitive restructuring, interoceptive exposure, discussion of safety behaviors, relapse prevention

This table provides detailed information on the exposure treatment materials and procedures and on additional interventions applied in participants of the included studies. It mentions the general exposure strategy that was similar in VR and in vivo. Moreover, it gives information on the type of HMD used for visual stimuli presentation, including data on image resolution and field of view (FoV). The image resolution is reported by the number of pixels arranged horizontally and vertically; the field of view is reported as diagonal FoV in degrees. If available, information on the movement mode in VR and on additional devices for tactile stimulation is provided. The table furthermore provides descriptions of the VR and in vivo exposure environments and mentions psychological interventions that were applied in addition to pure exposure treatment in the VR as well as for the in vivo exposure condition. Studies are sorted by the type of phobia and date of publication. N/A: no information available.

^aSeat with woofer under it to create noise and vibrations.

^bIn this study, a CAVE system was used in addition to HMD as an alternative mode for VR presentation. No significant effects of HMD vs. CAVE were found on outcome-measures.

^cImaginal exposure was conducted during in vivo exposure on a stationary plane.