Behavioral assessment in the CAVE
In order to assess MPA in a condition as real as possible on the different levels (subjective and physiological), a BAT is performed in the CAVE (software from VTplus GmbH, Institute of Psychology I at the University of Würzburg). The CAVE system is a room sized 4 × 3 × 3 m, in which a virtual environment is projected onto the four walls and floor via stereoscopic images. The stereoscopic impression is created by passive interference filtering glasses worn by the subjects [After finishing the preparations for the BAT (e.g. attaching the microphone, head tracker, and electrodes for measuring the heart rate), blood pressure and heart rate are measured. The musicians are instructed to behave and interact with the jury (e.g. respond to questions) as if it was a real audition. Also, they are briefed about the subjective fear ratings ranging from 0 “no fear at all” to 100 “maximum fear” that are assessed throughout the BAT over a microphone. When entering the CAVE, a physiological baseline for the HRV is recorded. Therefore the participants have to sit and to stand respectively one minute in a neutral CAVE (white walls) while doing nothing. After measuring the baseline, the subjects are asked to rate their anticipatory and maximum expected fear of the audition. Subsequently, they are told that the audition will start now and the CAVE shifts to display a waiting room in which the musicians find themselves waiting in front of the door of a big concert hall. To help the participants immersing into the situation, short, standardized instructions are read at the beginning of the waiting phase and when entering the stage. At the beginning and at the end of the waiting phase, the participants are asked to rate their actual fear (0-100). Thereafter, participants “enter the stage” by shifting the CAVE to display a concert hall with other musicians waiting in the background and people sitting in the audience. The musicians are instructed to wait for another minute until the jury will arrive, and to feel free to look around and prepare for their performance. Also they are asked again to rate their current fear (0-100). Finally the jury, consisting of two men and two women, pops up in the first row of the audience and another fear-rating (0-100) is assessed. When the jury appears they seem busy (e.g. looking down at their notes or around). After 30 s all the jury members lay back and start to look up at the participant and a male juror begins to greet the participant. He asks the musician to introduce her-/himself and the first piece he/she is going to perform. When the musician has finished answering, the juror reacts confirming the choice of the piece and asks the musician to start playing/ singing when ready. After three minutes, the participants are being interrupted by the jury even though they have not finished their first piece yet. Another fear rating is assessed asking for the maximum fear while playing (0-100) and the actual fear after having finished the first piece (0-100). Finally, a female jury member asks the musician for the second piece that the musician is going to present and prompts the participant to start the performance. Following the same procedure as for the first piece, the musician is being interrupted by the jury at latest after having played three minutes, which is followed by the fear ratings to assess the maximum fear while playing (0-100) and the actual fear after having finished the second piece (0-100). Thereafter, the female jury member says goodbye and asks the participants to wait outside. The audition is ended and the BAT ends with again recording a physiological baseline for the HRV in a neutral CAVE (e.g. white walls), same as at the beginning. After recording the baseline, the participants are asked for the last time to rate their actual fear (0-100) and are then asked to leave the CAVE. Outside the CAVE, blood pressure and heart rate are measured again and microphone, head tracker and electrodes are being removed.In addition, during the BAT, the musical performance is recorded by a recorder (Zoom H4n®) which is attached to a microphone stand in front of the musician.The total duration of the CAVE examination is estimated to last approximately 120 min of which 50 min are estimated for the BAT, its preparations and debriefing (e.g. attaching the microphone, head tracker and electrodes for measuring the heart rate, recording the physiological baseline and measuring heart rate and blood pressure before and after the BAT), 40 min to fill out the questionnaires, and 30 min to take blood and saliva samples in the beginning and at the end of the examination.Concerning the pieces of music, the participants are told two weeks in advance to present a slow and a virtuosic piece of music of moderate to high degree of difficulty, similar to a real audition. Participants have to present the same two pieces of music at all time points (T0 up to T2). The follow-up (T2) after six months also takes place at the CAVE and an appointment is made with the participants directly after the therapy respectively the assessment in the CAVE at T1. By doing so, we hope to promote participant retention and motivate them to complete follow-up.