# A Virtual Reality-Based Simulation Tool for Assessing the Risk of Falls in Older Adults
## 4 Results  
The participants reported high presence scores in the ITC-SOPI for all the components: Spatial Presence (Mean: 2.8; SD: 0.69), Engagement (Mean: 3.28; SD: 0.88), Naturalness (Mean: 3.67; SD: 0.84), and Negative Effects (Mean: 1.55; SD: 0.83). Examining the results, participants were highly engaged and perceived an ecologically highly valid VR environment. However, the spatial presence was slightly lower. It was also observed that participants' responses were low for the component of the negative effect of the environment (Figure 4). The mean score on the SUS was M = 73.8 (SD = 12.0) for the system's usability. This indicates a good usability score (>68) [58]. Table 1 shows the results from the repeated ANOVA, which was executed on all the 2 MST, 30 SCST, and CCS parameters. We found significant differences (\(p\) < 0.05) in three of the CCS speeds and track angles in the anterior-posterior axis (speed = 5, angle = \(-\)90; speed = 7, angle = 90; speed = 7, angle = \(-\)90). This indicates that the different CCS parameters can induce measurable behavioral differences. Figure 4: Box Plot Indicating the Results of the ITC-SOPI Questionnaire. The asterisks and circles are the far-out and far outliers, respectively. The maximum excursion of COP in the AP direction for all combinations of Angles (0, 45, 90, \(-\)45, \(-\)90) and Speeds (3 m/s, 5 m/s, 7 m/s, 9 m/s) was correlated with nearly all metrics of BBS metrics such as EOMeanScore, ECMeanScore, and Composite Mean, etc. (Table 2). However, no significant correlations were observed between the BBS metrics and the maximum excursion of COP in medial-lateral directions. The mean angles are the parameters where angles were ignored, speed limits were selected, and vice versa. The COP mean velocity for almost all combinations of Angles (0, 45, 90, \(-\)45, \(-\)90) and speed limits (3 m/s, 4 m/s, 5 m/s, 6 m/s) of the CCS was observed to be significantly correlated with the parameters of BBS. Again, these findings indicate that the CCS is effective at inducing behavioral responses and that the COP metrics of the CCS are consistent with those of the BBS. A Discriminant Analysis (DA) was performed to assess the sensitivity of the KAVE simulations to profile and classify participants as high-risk-falls or low-risk-falls based on the assessment conducted by the BBS. The participants who were classified in the higher 50 percentile predicted Composite Mean score (11 points) were referred to as high-risk falls, and those below were in low-risk falls. Several DA models, such as linear, pseudolinear, diaglinear, pseudoquadratic, diagquadratic, and support vector machine (SVM), were built along with the leave-one-out cross-validation method to evaluate the performance of the models (accuracy, recall, precision, and F-score). The selected input features for the classifier included CCS speeds and turning angles, their average responses, 2 MST, 30 SCST, and HR. A DA with each feature was performed to establish the prediction power of each feature modality; additionally, a posterior step-wise regression approach was used to perform the feature selection. Discrimination accuracies differ substantially, with the best classification for HR at 55%, CCS at 72%, 2 MST and 30 SCST at 72%, and 100% for the combined features through a step-wise regression (Table 3). The selected features were the maximum excursion of the COP for high speeds at high turning angles for both AP and ML, the mean of the speeds at 45-degree turning angles for both AP and ML, the mean of the angles at high speeds in the AP direction, and the COP at high speeds for no rotation. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Cable Car Speed and Trajectory Angles** & **F** & **Sig.** \\ \hline cable\_car\_speed5\_angle\_minus\_90 & 4.461 & 0.050 \\ cable\_car\_speed7\_angle90 & 7.11 & 0.016 \\ cable\_car\_speed7\_angle\_minus\_90 & 5.10 & 0.037 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Maximum excursion of COP in anterior–posterior axis for cable car speed and trajectory angles.