“DoC-feeling”: a new behavioural tool to help diagnose the Minimally Conscious State

Abstract Objectives The clinical distinction between vegetative state/unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS) is a key step to elaborate a prognosis and formulate an appropriate medical plan for any patient suffering from disorders of consciousness (DoC). However, this assessment is often challenging and may require specialized expertise. In this study, we hypothesized that pooling subjective reports of the level of consciousness of a given patient across several nursing staff members can be used to clinically detect MCS. Setting and Participants Patients referred for consciousness assessment were prospectively screened. MCS (target condition) was defined according to the best Coma Recovery Scale-Revised score (CRS-R) obtained from expert physicians (reference standard). “DoC-feeling” score consisted in the median value of multiple ratings of patient’s behavior observation pooled from multiple staff members during a week of hospitalisation (index test). Individual ratings were collected at the end of each shift using a 100mm visual analog scale, blinded from the reference standard. Diagnostic accuracy was evaluated using area under the receiver operating characteristic curve (AUC), sensitivity and specificity metrics. Results 692 ratings performed by 83 nursing staff members were collected from 47 patients. Twenty patients were in a UWS and 27 in a MCS. DoC-feeling scores obtained by pooling all individual ratings obtained for a given patient were significantly greater in MCS than in UWS patients (59.2 mm IQR: 27.3-77.3 vs. 7.2 mm IQR: 2.4-11.4; p<0.001) yielding an AUC of 0.92 (95%CI: 0.84-0.99). Conclusions DoC-feeling capitalizes on the expertise of nursing staff to evaluate patients’ consciousness. Together with the CRS-R as well as with brain imaging, DoC-feeling might improve diagnostic and prognostic accuracy of DoC patients. Strengths and limitations of this study We designed a new behavioural tool called “DoC-feeling” to help face the clinical challenge of the detection of Minimally Conscious State in patients suffering from disorders of consciousness (DoC) “DoC-feeling score” quantifies nursing staff’s subjective perception of patient’s consciousness by pooling multiple assessments obtained from multiple caregivers (“wisdom of the crowds”) This score which requires no particular training showed a very good accuracy when compared to the gold standard (repeated expert clinical assessment using the Coma Recovery Scale – Revised (CRS-R)) A validation in a separate cohort would help to determine its place in consciousness assessment This score should be tested not only against the CRS-R but also against brain-imaging techniques to test for its capacity to detect covert signs of consciousness