# \"Scoliosis 3D\"-A Virtual-Reality-Based Methodology Aiming to Examine AIS Females' Body Image
## 3 Results
### Experimental Procedures  
Based on the \"Avatar Scoliosis 3D\" application, an experimental procedure using a library of realistic virtual-3D avatars to allow for realistic scoliosis-related body-deformity manipulations and a naturalistic-scenario presentation of these avatars was developed. In general, the investigator provides all participants with a verbal description of the purpose of the VR tasks, via the \"Avatar scoliosis 3D\", explaining the components of the VR experience. To sum up, participants are told that they will be participating in a study examining their perception of actual and desired body shape. In particular, the procedure comprises two experimental sessions (E1 and E2), in which avatars are presented on an immersive life-size stereoscopic display that mimics in virtual reality the situation of looking at oneself in a mirror. Therefore, participants will complete two method-of-adjustment tasks (MoA), the first referring to current body shape (E1) and the second referring to ideal body shape (E2). At the beginning of the procedure, each participant is informed that, based on real-patient body scans, a set of bodies will be generated. Participants are also told that the presented avatars can either represent their body exactly or be a modified version of their body, gradually made less or more deformed. In the E1 and E2 tasks participants are shown each avatar, corresponding to the following ranges of Cobb's angle that were selected before: (1) Cobb angle of 10-19; (2) Cobb angle of 20-29; (3) Cobb angle of 30-39; (4) Cobb angle of 40-49; (5) Cobb angle of 50-59; (6) Cobb angle of 60-69; (7) Cobb angle of 70-79 (Figures 3 and 4). Participants are shown the avatar with no time limit, and have to adjust it to their current [E1] or ideal [E2] body shape [15]. Then, body tracking is turned on and the patient is able to see the selected avatar in motion. Avatar no. 1 presents a Cobb angle of 10-19; no. 2 presents a Cobb angle of 20-29; no. 3 presents a Cobb angle of 30-39; no. 4 presents a Cobb angle of 40-49; no. 5 presents a Cobb angle of 50-59; no. 6 presents a Cobb angle of 60-69; and no. 7 presents a Cobb angle of 70-79. At the beginning of each experiment, the investigator provides the instruction, after which the avatar appears. In E1, the instruction given is as follows: \"Please adjust the body until it matches your current body!\". In E2, the instruction is modified to \"Please adjust the body shape on screen until it matches your ideal, desired body shape\". During the session, it is possible to change the selected avatar to one with a different Cobb angle (lower or higher) if the patient's perception is incompatible with the visualization of the initial avatar. Although there is no set time limit to a session, participants are instructed to rely on their instinct and to not linger too long over a decision. Furthermore, after the session, participants complete a questionnaire in which they are asked to rate on a Likert scale from 1 (not at all) to 7 (very much) a) how similar they perceived the two finally selected avatars to be (overall impression) and b) whether, as the avatars were presented on an immersive life-size stereoscopic display mimicking looking at a mirror reflection of themselves in virtual reality, they could identify with the presented avatars. [PERSON] et al. [21] observed such ratings to be sensitive to dissimilarities between avatar and participant. The experimental procedure for control, healthy female adolescents was also developed, for comparative purposes. The procedure comprises an experimental session with Experiment 1 (E1). Specifically, participants complete one method-of-adjustment task (MoA), referring to the estimation of the current (E1) body shape. The only instruction is, \"Please adjust the body until it matches your current body!\".