# Validating the Threat of a Virtual Reality Clinical Environment: A Mixed Methods Study
## 3 Results
### Physiological Threat Measurement: Cortisol Concentration  
There was a significant difference in the cortisol concentration measured across time in the subjects exposed to the threat condition (\(\chi^{2}\)(2) = 13.83, \(p\) < 0.001). Post hoc comparisons revealed a significant decrease in the cortisol concentration from pre-VR exposure to 20 min post-exposure (cortisol Mdn = 0.15 \(\pm\) 0.24 versus cortisol20 Mdn = 0.1 \(\pm\) 0.2; \(p\) = 0.001 \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & & & & & & & & & & & & & \\ \hline \multirow{2}{*}{**Adjective**} & **SD** & **D** & **N** & **A** & **SA** & **Mdn** & **SD** & **D** & **N** & **A** & **SA** & **Mdn** & \(p\)**-Value** \\ \cline{2-13}  & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(IQR)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(IQR)** & **MWU** \\ \hline \multirow{2}{*}{Threatening \(\cdot\)} & 2 & 4 & 3 & 4 & 0 & 3 & 7 & 5 & 1 & 0 & 0 & 1 & \\  & (15) & (31) & (23) & (31) & (0) & (2) & (54) & (38) & (8) & (0) & (0) & (1) & \(p\) = 0.008 \({}^{*}\) \\ \hline \multirow{2}{*}{Stressful \(\cdot\)} & 1 & 1 & 2 & 7 & 2 & 4 & 4 & 7 & 2 & 0 & 0 & 2 & \\  & (8) & (8) & (15) & (54) & (15) & (1) & (31) & (54) & (15) & (0) & (0) & (1) & \(p\) < 0.001 \({}^{*}\) \\ \hline \multirow{2}{*}{Unpleasant \(\cdot\)} & 0 & 1 & 1 & 9 & 2 & 4 & 5 & 7 & 0 & 1 & 0 & 2 & \\  & (0) & (8) & (8) & (69) & (15) & (0) & (38) & (54) & (0) & (8) & (0) & (1) & \(p\) < 0.001 \({}^{*}\) \\ \hline \multirow{2}{*}{Calming \(\bullet\)} & 5 & 6 & 1 & 0 & 1 & 2 & 0 & 0 & 2 & 10 & 1 & 4 & \\  & (38) & (46) & (8) & (0) & (8) & (1) & (0) & (0) & (15) & (77) & (8) & (0) & \(p\) < 0.001 \({}^{*}\) \\ \hline \multirow{2}{*}{Safe \(\bullet\)} & 0 & 5 & 5 & 2 & 1 & 3 & 0 & 0 & 1 & 6 & 6 & 4 & \\  & (0) & (38) & (38) & (15) & (8) & (2) & (0) & (0) & (0) & (8) & (46) & (46) & (1) & \(p\) < 0.001 \({}^{*}\) \\ \hline \multirow{2}{*}{Reassuring \(\bullet\)} & 4 & 7 & 1 & 1 & 0 & 2 & 0 & 0 & 4 & 6 & 3 & 4 & \\  & (31) & (54) & (8) & (8) & (0) & (1) & (0) & (0) & (31) & (46) & (23) & (2) & \(p\) < 0.001 \({}^{*}\) \\ \hline \multirow{2}{*}{Cronbach’s Alpha} & \multicolumn{4}{c}{\(\alpha\) = 0.88} & \multicolumn{4}{c}{\(\alpha\) = 0.74} & \\ \hline Median Threat Score \({}^{*}\) & \multicolumn{4}{c}{22/30} & \multicolumn{4}{c}{\(10/30\)} & \multicolumn{4}{c}{\(p\) < 0.05} \\ \hline \hline \end{tabular}  
* Threat-associated and \(\bullet\) non-threat-associated adjectives, measured on a five-point Likert scale. Frequency percentages are reported for each statement. \(n\) = 26 (13 vs. 13) subjects. SD—Strongly Disagree, D—Disagree, N—Neither Agree nor Disagree, A—Agree, SA—Strongly Agree. Mdn (IQR) presented for all adjectives; however, responses to ‘safe’ and ‘threatening’ in the Threat condition only were normally distributed. \({}^{*}\) Statistically significant difference calculated using Mann–Whitney U test (MWU). \({}^{*}\) Threat scores are summed scores including transformed values.  
\end{table} 
Table 1: Subjects’ perceptions of threat associated with two clinical virtual reality environments. Bonferroni-corrected). There was no significant difference between the cortisol concentrations at timepoints 20 and 26 min post-VR exposure (cortisol20 Mdn = 0.1 \(\pm\) 0.2 versus cortisol26 Mdn = 0.12 \(\pm\) 0.2; \(p\) = 0.922), but there was a significant decrease from pre-VR exposure to 26 min following exposure (cortisol0 Mdn = 0.15 \(\pm\) 0.24; cortisol26 Mdn = 0.12 \(\pm\) 0.2; \(p\) = 0.03; Figure 3). There was no significant difference in cortisol found across time in the non-threat condition (cortisol0 M = 0.18 \(\pm\) 0.09, cortisol20 M = 0.14 \(\pm\) 0.05, cortisol26 M = 0.17 \(\pm\) 0.09; F(2,24) = 1.68, \(p\) = 0.2), indicating that cortisol did not change with VR exposure (Figure 3).