# Postural Control Disturbances Induced by Virtual Reality in Stroke Patients
## 3 Results  
Twenty-two SP and 15 HA were screened, where 17 SP were not included for the following reasons: six for wearing of an orthosis, six could not stand for one minute, two  
Figure 1: General experimental setup (**A**), static virtual environment (**B**), and dynamic virtual environment in sparse crowd and wide space (**C**), dense crowd and wide space (**D**), sparse crowd and narrow space (**E**), and dense crowd and narrow space (**F**) conditions.  
for visual trouble, one for motion sickness, one for hip surgery, and one for cognitive impairment. As shown in Table 1, the socio-demographic variables of both groups were homogeneous. Clinical characteristics of SP were a Barthel index of 87 [70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89; 90; 91; 92; 93; 94; 95; 96; 97; 98; 99; 100; 93; 90; 94; 98; 99; 11; 11; 12; 13; 14; 15; 16; 17; 18; 19; 19; 12; 14; 19; 13; 15; 17; 19; 16; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36]; and FES-I of 26.6 [16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36]. There were four left and one right superficial sylvian ischemic strokes and three of them had aphasia. SP had a NIHSS (National Institutes of Health Stroke Scale) of 6 [6; 7; 8; 9] at admission into the department.  
Postural control data are presented in Figure 2. There were no significant differences of CoP velocity displacement between SP and HA in open eyes (\(p\) = 0.275), closed eyes (\(p\) = 0.266), and static virtual environment (\(p\) = 0.098) conditions. In contrast, our results revealed that CoP velocity was greater in SP than HA for all dynamic virtual environment conditions (\(p\) < 0.05).  
\begin{table}
\begin{tabular}{l c c c} \hline \hline \multicolumn{1}{c}{**Parameters**} & **Stroke Patients** & **Healthy Adults** & \(p\)**-Value** \\ \hline Population (N) & 5 & 15 & - \\ Women (N (\%) & 2 (40) & 9 (60) & 0.479 \\ Age (years) & 61.2 \(\pm\) 7.1 & 59.1 \(\pm\) 2.8 & 0.334 \\ BMI (Kg/cm\({}^{2}\)) & 25.9 \(\pm\) 2.2 & 25.7 \(\pm\) 3.9 & 1 \\ \hline Barthel & 87.0 [70:100] & - & - \\ PASS & 33.6 [32:36] & - & - \\ FES-I & 26.6 [16:39] & - & - \\ NIHSS & 6.0 [6:9] & - & - \\ \hline
**CoP velocity** (mm.s\({}^{-1}\)) & & & \\ Open Eyes & 13.1 [11.0; 18.0] & 11.8 [9.2; 14.0] & 0.275 \\ Closed Eyes & 19.7 [18.8; 21.3] & 17.6 [14.9; 22.0] & 0.266 \\ Static virtual environment & 15.6 [13.6; 15.8] & 10.7 [9.7; 12.9] & 0.098 \\ Dynamic virtual environment SW & 15.1 [14.8; 15.9] & 10.7 [9.7; 14.0] & 0.025 \({}^{*}\) \\ Dynamic virtual environment DW & 16.9 [15.8; 18.2] & 12.2 [10.5; 14.7] & 0.015 \({}^{*}\) \\ Dynamic virtual environment SN & 16.0 [13.4; 18.9] & 11.7 [8.7; 13.8] & 0.025 \({}^{*}\) \\ Dynamic virtual environment DN & 18.2 [18.1; 19.2] & 13.0 [11.3; 17.2] & 0.042 \({}^{*}\) \\ \hline
**Vrcost (\%)** & & & \\ Static virtual environment & 17.7 & 2.8 & 0.23 \\ Dynamic virtual environment SW & 28.8 & 4.5 & 0.197 \\ Dynamic virtual environment DW & 31.2 & 13.1 & 0.081 \\ Dynamic virtual environment SN & 38.1 & 2.9 & 0.081 \\ Dynamic virtual environment DN & 51.9 & 20.9 & 0.033 \({}^{*}\) \\ \hline
**VAS (0–10)** & & & \\ Open Eyes & 2.0 \(\pm\) 2.1 & 1.1 \(\pm\) 1.2 & 0.479 \\ Closed Eyes & 3.2 \(\pm\) 2.6 & 2.2 \(\pm\) 1.9 & 0.403 \\ Static virtual environment & 2.3 \(\pm\) 1.7 & 1.3 \(\pm\) 1.7 & 0.215 \\ Dynamic virtual environment SW & 2.4 \(\pm\) 2.1 & 1.2 \(\pm\) 1.2 & 0.215 \\ Dynamic virtual environment DW & 2.6 \(\pm\) 1.8 & 1.5 \(\pm\) 1.6 & 0.25 \\ Dynamic virtual environment SN & 2.4 \(\pm\) 2.1 & 1.3 \(\pm\) 1.3 & 0.271 \\ Dynamic virtual environment DN & 3.5 \(\pm\) 2.6 &Furthermore, the Vrcost appeared significantly higher for SP than HA in the dynamic virtual environment DN condition (51.9% for SP and 20.9% for HA, \(p\) = 0.033). Vrcost did not appear significantly different in any other conditions (\(p\) > 0.05). No group effect was observed for difficulty in identifying feelings (VAS) for all conditions.