Nociception Coma Scale-Revised Allows to Identify Patients With Preserved Neural Basis for Pain Experience

The Nociception Coma Scale-Revised (NCS-R) was developed to help assess pain in patients with disorders of consciousness (DOC). Several studies have shown its sensitivity in assessing response to acute noxious stimuli. However, they failed to determine a reliable cut-off score that could be used to infer pain processing in these patients. This retrospective cross-sectional study aimed to determine a NCS-R cut-off score supporting preserved neural basis for pain experience, based on brain metabolism preservation as measured by fluorodeoxyglucose positron emission tomography (FDG-PET). We included patients in unresponsive wakefulness syndrome (UWS) confirmed by the FDG-PET and examined the NCS-R total scores. As the highest score was 4, we defined the cut-off to be 5 and compared the brain metabolism of these patients to matched patients with DOC and a NCS-R cut-off score ≥5 (ie, potential pain), as well as healthy subjects. We found a higher global cerebral metabolism in healthy subjects compared to both patient groups and also in patients with potential pain compared with FDG-PET confirmed UWS. We observed a preserved metabolism in the left insula in patients with potential pain compared with FDG-PET confirmed UWS. PERSPECTIVES: Our data suggest that using the cut-off score of 5 could be helpful to improve pain management in patients with DOC. Future studies should focus on patients showing scores below this cut-off to better characterize their profile and improve care.