Materials
The self-hypnosis device used was the OnComfort-Sedakit™ (Oncomfort, Wavre, Brabant-Wallon, Belgique). This medical device comprises an HMD mask Samsung Gear VR powered by Oculus with a Samsung S7 mobile phone (Samsung Electronics, Seoul, South-Korea) or Pico G2 (PICO-interactive, Qingdao, Shandong, China), and headphones for tone and noise reduction.The virtual reality software displays an underwater world. A whale swims in front of the user, inviting him to breathe at the frequency of its tail. A prerecorded discourse guides the patient through autohypnosis. To maximize the effects of VR, it is important to let the patient concentrate on the session. Thus, verbal communication is avoided, although people can freely speak if necessary. Throughout the experience, the patients can move their head freely to explore the virtual environment. A relaxed state is facilitated by binaural beats [The operator can select the duration beforehand, this determines the length of the different hypnotic phases (i.e., induction, deepening, suggestion, and return). The duration may also be shortened or prolonged per-procedure [