# Augmented Reality, Mixed Reality, and Hybrid Approach in Healthcare Simulation: A Systematic Review
## 3 Results
### Evaluation of Simulators (FQ9-10)
The sample sizes are five (expert physicians), five (undergraduate students), and seven ( Veterinary students), respectively. In [29], the authors evaluate the effectiveness of the system to teach anatomy and to grasp the basics of a specific orthopedic surgery. In [32], both content validity and usability evaluation are performed in terms of how easy to use the simulator is. In [39], the authors perform only face validity. In [40], the authors report face, content, construct, skills improvement validity, and criterion validity (often divided into concurrent and predictive validity). They compare the developed simulator and the PERC Mentor. Simulator's face and content validity are evaluated by 38 expert surgeons in [22] and by 40 subjects in [34]. In both of these studies, a questionnaire on the realism and the usefulness of simulators is used, and in [22] the authors also address questions on the value of AR for medical training. Overall, the opinions of the users are very positive in all studies. Finally, in [34], proficiency level is also assessed. Concurrent validity is reported in four studies [25; 30; 37; 40]. In [25], the authors evaluate the performance of 20 medical students in robotic surgery sessions before and after training using ProMIS and the LapSim. The results show that the use of ProMIS and LapSim simulators in conjunction with each other can improve robotic console performance. In [37], laparoscopic skills are assessed in ProMIS tasks before and after LapSim training to clarify whether this training improves operation skills: the results confirm an improvement. In [30], the authors compare physical simulation and AR simulation of central venous catheters mannequin. The results show a significant difference in the adherence level between the AR group and the non-AR group, owing to the real-time feedback the AR group received as they performed the procedure. Additionally, tests of usability, workload, and ergonomics of AR glasses are performed. [PERSON] et al. [33] report both face and construct validity of their simulator. Face validity is evaluated by 20 users (10 novices and 10 expert surgeons) using a questionnaire about the realism of the VR objects and the interaction between the instruments and the VR objects, and the difficulty of the task and the lack of force feedback during tool-object interaction. Construct validity is evaluated in three tasks between two experience groups. The results demonstrate highly significant differences in all performance metrics. Validity and technical evaluation: Four studies out of 23 report face and content validity and technical evaluation [24; 26; 41; 44]. With regard to face and content validity, all studies use a questionnaire on the realism and the usefulness of the simulators; in [26; 44], the questions also address the value of AR for medical training. Overall, the opinions of the users are very positive. Additionally, in [26; 44] the authors evaluate the robustness of the simulator hardware. The users enrolled in all studies are five expert surgeons in [26], 13 clinicians in [24], 10 expert surgeons in [44], six novices, and four expert surgeons in [41]. With regard to the technical evaluation, in [26; 44] the accuracy of AR visualization is evaluated as adequate for training purposes. In [24], the authors perform three tests to measure eventual damage of EM sensors during embedding steps, the correspondence between planned and actual sensor positions, and the correspondence between real and virtual scenarios; all the results were coherent. In [41], the authors assess both the simulator reliability measuring the precision of the tracking and the simulator face, content, and construct validity. All users agree on the realism of the simulator and on the fact that practice on the simulator would improve their intraoperative wire navigation performance. About the content validity assessment, the authors compare the desired task characteristics from the design specification checklist with the features of the assembled simulator.