Higher nociception scores in minimally conscious state compared to unresponsive wakefulness syndrome and positive correlations among CRS-R, GCS-P and NCS-R in Patients with Disorders of Consciousness

Background: One of the greatest challenges in understanding pain is the difficulty in assessing or recognizing it in patients with disorders of consciousness (DOC). Objective: To compare the nociception using the Nociception Coma Scale Revised (NCS-R) in DOC. Methods: In the first phase, patients with DOC were evaluated using the Coma Recovery Scale-Revised (CRS-R) to diagnose the type of DOC, either Unresponsive Wakefulness Syndrome (UWS) or Minimally Conscious State (MCS). Subsequently, the Modified Glasgow Coma Scale-Pupils Score (GCS-P) was applied, and the occurrence of pain was assessed using the NCS-R. Main Outcome Measures: Score of NCS-R from UWS and MCS patients and correlations among CRS-R, GCS-P and NCS-R. In the second phase, a subgroup of patients with a cutoff score of ≥5 on the NCS-R was selected to evaluate the analgesic effect. Results: The mean NCS-R scores were higher in the MCS group (n=42) compared to the UWS group, (n=14) with differences mainly attributed to the motor, verbal and facial components. Strong positive correlations were observed for the whole sample between NCS-R and GCS-P (r=0.788; p<0.001); between CRS-R and GCS-P (r=0.754; p<0.001) and between NCS-R and CRS-R (r=0.796; p<0.001). In the UWS group, a moderate positive correlation was also observed. In phase 2, in the NCS-R assessment, the two groups showed similar mean score. Conclusions: We found that the UWS group had lower NCS-R scores than the MCS. In addition, across the entire sample and in the UWS group, the three scales used (CRS-R, GCS-P and NCS-R) showed positive correlations.