Designing and piloting an innovative mixed reality experience to deliver exposure therapy for contamination-related obsessive-compulsive disorder

The mixed reality-based exposure and response prevention (MERP) experience was designed by Liminal VR. It will be deployed on the Meta Quest 3, a mixed reality headset that superimposes computer-generated imagery on a real-world view. Within the program, participants will be exposed to and asked to interact with virtual contaminants projected onto a real table which are intended to trigger their contamination-related Obsessive-Compulsive Disorder (C-OCD) concerns. Participants will use their own hands to manipulate the virtual objects. There are three experiences in the exposure – abstract, realistic, and hyper-realistic. The abstract and hyper-realistic experiences will respectively use a half-eaten burger or a half-eaten mouldy burger as the contaminant, while the realistic experience will have a mouldy burger sealed in a plastic box as the contaminant. Each experience will be delivered once only and each take 5 minutes, and the order of experiences will be randomised for each participant. There will be a 5-minute break between each experience where participants will be asked to engage in a neutral filler task (spot the difference puzzles) while still wearing the headset. After putting on the headset, at the start of each experience, participants will see virtual objects projected onto the table. This includes a virtual partition dividing the table into halves – on the left will be the contaminant (burger) with a blue block placed on top of it and a grey block on the table next to it; the right side will have four differently coloured blocks. Participants will be instructed to place their phone on the bottom right corner of the table. They will then be guided to look at the contaminant and to move the grey block to the right side of the table. Then, they will be prompted to move the blue block to the right side of the table and build a tower with all the blocks. Finally, they will be prompted to interact with their phone on the table by unlocking it and finding a photo that makes them feel neutral. Then the experience will end. The table will be cleaned prior to starting the ambiguous experience. The student investigator will monitor participant adherence to the MERP experience, which will be accomplished by mirroring what the participant sees through their headset onto the student investigator’s phone using the Meta Quest application.