# An Immersive Virtual Reality Simulator for Echocardiography Examination
## 3 Results
### Validation Results of the Echocardiography Examination Simulator  
As mentioned in Section 2.6, a validity assessment of the echocardiography examination simulator was conducted using a questionnaire method with 58 medical university students. Based on the questionnaire results, we calculated response rates for each item, as well as the averages and standard deviations of responses for individual questions within each item to evaluate the validity of the simulator. Figure 21 shows the response rates for each item, and Figure 22 shows the averages and standard deviations for individual questions within each item. Figure 21: Graph of response rates for each item. In the resolution section, responses were very good (30.17%), good (42.24%), normal (24.14%), bad (1.72%), and very bad (1.72%), indicating that over 72% of the responses were positive. For the four questions in this category, an average of 3.97 and a standard deviation of 0.88 were calculated. These results indicate that the examination images presented in the echocardiography examination simulator are appropriately provided at the probe contact location, and users are satisfied with the sharpness of the provided images. However, the average score for question 4 was lower compared to other questions. This requires restraining the movement of interactive devices to maintain the previous image before medical university students proceed to the next step when displaying echocardiography examination images. However, the medical university students participating in the evaluation have no prior experience with interactive device usage. As a result, precise operations such as restraining the movement of interactive devices were challenging, ultimately resulting in low average scores. In the accuracy section, very good (31.38%), good (36.55%), normal (24.83%), bad (5.17%), and very bad (2.07%) responses were derived, indicating positive results of 71% or more. For the five questions, an average of 3.90 with a standard deviation of 0.98 was calculated. These results suggest that the representation of models, the movement of objects, and the processes of echocardiography examination within the simulator closely resemble real scenarios. However, the average score for question 3 was lower compared to the other questions. This is because the ratio of haptic device movement to virtual environment movement is different. Representing movement in a 1:1 ratio poses challenges in performing interactions within the virtual environment using the limited movement range of the haptic device. Therefore, the ratio of haptic device movement to virtual environment movement was adjusted to 1:2. Since the validity assessment targeted students with no prior experience in using interaction devices, the low average score was a result of their unfamiliarity with the movement ratio adjustment. In terms of usability, very good (30.17%), good (38.36%), normal (22.84%), bad (6.47%), and very bad (2.16%) responses were derived. For the four questions, an average of 3.88 with a standard deviation of 0.98 was calculated. In questions related to simulator operation, high average scores were obtained, but lower average scores were obtained in questions related to interaction and visualization. For question 1, the low average score is attributed to the difficulty in sensing haptic feedback when using the controller as an interaction  
Figure 22: Average and standard deviations for each question by item. device. Regarding question 2, difficulties such as motion sickness, challenges in adjusting focus, and the inability to wear glasses when using the HMD for the first time resulted in a lower average score due to the challenging visual experience. In the applicability section, very good (38.79%), good (35.78%), normal (18.10%), bad (4.74%), and very bad (2.59%) were derived. For the four questions, an average of 4.03 with a standard deviation of 1.0 was calculated. The echocardiography examination simulator has been confirmed to be sufficiently utilizable for educational and instructional purposes.