A sensitive scale to assess nociceptive pain in patients with disorders of consciousness
- 1Coma Science Group, Cyclotron Research Centre, University of Liège, Liège, Belgium
- 2Department of Neurology, University Hospital of Liège, Liège, Belgium
- 3Department of Cognitive Sciences, University of Liège, Liège, Belgium
- 4Moss Rehabilitation Research Institute, Philadelphia, Pennsylvania, USA
- Correspondence to Dr Caroline Schnakers, Coma Science Group, Cyclotron Research Centre, Sart Tilman, B30, University of Liège, 4000 Liège, Belgium;
Contributors CC: collection, analysis and interpretation of the data, drafting the manuscript. SM, SL: revising the manuscript. JW: conceptualisation of the study and revising the manuscript. SC: design of the study, analysis and interpretation of the data, drafting the manuscript. CS and CC conducted the statistical analysis.
- Received 16 April 2012
- Revised 23 July 2012
- Accepted 1 August 2012
- Published Online First 20 August 2012
Objective To determine the sensitivity of the Nociception Coma Scale (NCS), the first scale developed to assess nociceptive pain in vegetative state and minimally conscious state patients, in comparing behavioural changes in response to noxious versus non-noxious stimulation.
Methods The NCS was administered to assess patients' responses in three conditions: (1) baseline (observation of spontaneous behaviours), (2) non-noxious/tactile stimulation (taps on the patient's shoulder), and (3) noxious stimulation (pressure on the nail bed).
Results We included 64 patients (27 vegetative state and 37 minimally conscious state; age range 20–82 years; 22 traumatic brain injury; 21 in the acute stage). The NCS total scores and subscores (motor, verbal and facial) were higher for the noxious versus the non-noxious stimulation conditions. We did not observe a difference between the non-noxious and the noxious stimulation conditions for the visual subscale. We also found a NCS cut-off value of 4 differentiating the patients receiving a noxious stimulation from patients receiving a non-noxious stimulation. The exclusion of the visual subscale increased the cut-off sensitivity (from 46% to 73%; specificity of 97% and accuracy of 85%).
Conclusion We propose a new version of the NCS excluding the visual subscale, the NCS-R, which constitutes a highly sensitive tool to assess responses to nociceptive pain in severely brain injured patients.
- Nociceptive pain
- brain injury
- vegetative state
- minimally conscious state
- head injury
- persistent vegetative state
- functional imaging
- clinical neurology
- cognitive neuropsychology
- cognitive electrophysiology
Funding This study was supported by the Belgian Federal Public Health, the National Funds for Scientific Research (FNRS), James S. McDonnell Foundation, Mind Science Foundation, European Commission (Mindbridge, DISCOS, DECODER & COST), Concerted Research Action (ARC 06/11-340), Public Utility Foundation ‘Université Européenne du Travail’, ‘Fondazione Europea di Ricerca Biomedica’ and the University of Liège. CS is postdoctoral researcher, CC is research fellow, and SM and SL are senior research associates at FNRS.
Competing interests None.
Ethics approval Ethics Committee of the Faculty of Medicine of the University of Liège.
Provenance and peer review Not commissioned; externally peer reviewed.