What impact can hospitalization environment produce on the ANS functioning in patients with Unresponsive Wakefulness Syndrome? - 24-hour monitoring.

: Studies showed that the recovery of patients with Unresponsive Wakefulness Syndrome (UWS) is also correlated to the recovery of circadian rhythms. In this study, we observed the correlations between patients with UWS biometrical and ambient parameters. : A dedicated monitoring system was realized to record and correlate the level of noise and luminosity with biometric Heart Rate (HR), Heart Rate Variability (HRV) and Breath Rate (BR) parameters. Eleven patients with UWS were recruited and monitored for 13 ± 7 days. Correlation of ambient and biometric parameters was analyzed by Spearman's test. Wilcoxon's test was used to compare the biometric parameters in two different moments of daily activity in the rehabilitation unit (night and day). Patients showed a moderate negative or positive correlation between biometric and ambient parameters. : Significant differences between night and morning (0.0001 < p ≤ 0.001) were found for HR, HRV and BR in seven, five and four patients, respectively, at Wilcoxon's test. HR and BR were higher during the night while HRV was lower. : In patients with UWS, lower HRV and higher HR and BR during the night might be indicative of interference in sleep/wake cycles. The modifications of the environment surrounding the patient due to the unit procedures of the staff and/or some interaction modalities of the relatives may have an effect on residual endogenous mechanisms of self-regulation. However, differences between night and day in the biometrical parameters are not necessarily linked to the changes in the environment care unit.