Researcher Anouk Keizer (https://www.anoukkeizer.com/) wanted to translate the rubber hand illusion to a more sensitive body part: the belly. In the rubber hand illusion a participant puts their hand on a table next to a rubber hand. The real hand is hidden from view by a screen. If the experimenter then brushes the real and rubber hand simultaneously the multi-sensory experience of the rubber hand (visual and touch) will strengthen the illusion that the rubber hand is the participant's real hand. Unfortunately, translating this illusion to other body parts is not so simple.
We decided that the most convincing way to show a participant an equivalent of a "rubber belly" was to use VR. Since we did this experiment in 2014 Oculus' DK1 and DK2 were the obvious choice. That took care of the visual aspect, but not the sensory part. The touch controllers or Vive wands didn't exist yet, the Wiimote lacked accurate motion tracking and the Leap Motion's working space was too small. We turned to the Razer Hydra (https://en.wikipedia.org/wiki/Razer_Hydra) because it was accurate, had low latency and was easy to carry around and set up.
The hydra's buttons enabled the researcher to do a quick calibration of the Hydra on the participant's belly. The touch was then translated to the correct part of the virtual avatar so that touch and visuals matched up. The researcher furthermore could enable an asynchronous control condition, as well as influence the avatar's skin color to both realistic and unrealistic tones.
In addition to resulting in published papers with anorexia patients researcher Silvia Serino has used the tool with obesitas (https://scholar.google.com/citations?user=-XfC9U0AAAAJ&hl=nl)