Nociception Coma Scale–Revised Scores Correlate With Metabolism in the Anterior Cingulate Cortex

Abstract

Background. The Nociception Coma Scale–Revised (NCS-R) was recently validated to assess possible pain perception in patients with disorders of consciousness. Objective. To identify correlations between cerebral glucose metabolism and NCS-R total scores. Methods. [18F]-fluorodeoxyglucose positron emission tomography, NCS-R, and Coma Recovery Scale–Revised assessments were performed in 49 patients with disorders of consciousness. Results. We identified a significant positive correlation between NCS-R total scores and metabolism in the posterior part of the anterior cingulate cortex, known to be involved in pain processing. No other cluster reached significance. No significant effect of clinical diagnosis (vegetative/unresponsive vs minimally conscious states), etiology or interval since insult was observed. Conclusions. Our data support the hypothesis that the NCS-R total scores are related to cortical processing of nociception and may constitute an appropriate behavioral tool to assess, monitor, and treat possible pain in brain-damaged noncommunicative patients with disorders of consciousness. Future studies using event-related functional magnetic resonance imaging should investigate the correlation between NCS-R scores and brain activation in response to noxious stimulation at the single-subject level.