Diagnostic accuracy of the CRS-R index in patients with disorders of consciousness

ABSTRACT

Objective: To obtain a CRS-R index suitable for diagnosis of patients with disorders of consciousness (DOC) and compare it to other CRS-R based scores to evaluate its potential for clinics and research.

Design: We evaluated the diagnostic accuracy of several CRS-R-based scores in 124 patients with DOC. ROC analysis of the CRS-R total score, the Rasch-based CRS-R score, CRS-R-MS and the CRS-R index evaluated the diagnostic accuracy for patients with the Unresponsive Wakefulness Syndrome (UWS) and Minimally Conscious State (MCS). Correlations were computed between the CRS-R-MS, CRS-R index, the Rasch-based score and the CRS-R total score.

Results: Both the CRS-R-MS and CRS-R index ranged from 0 to 100, with a cut-off of 8.315 that perfectly distinguishes between patients with UWS and MCS. The CRS-R total score and Rasch-based score did not provide a cut-off score for patients with UWS and MCS. The proposed CRS-R index correlated with the CRS-R total score, Rasch-based score and the CRS-R-MS.

Conclusion: The CRS-R index is reliable to diagnose patients with UWS and MCS and can be used in compliance with the CRS-R scoring guidelines. The obtained index offers the opportunity to improve the interpretation of clinical assessment and can be used in (longitudinal) research protocols.

Abbreviations: CRS-R: Coma Recovery Scale-Revised; CRS-R-MS: Coma Recovery Scale-Revised Modified Score; DOC: Disorders of Consciousness; MCS: Minimally Conscious State; UWS: Unresponsive Wakefulness Syndrome; ROC: Receiver Operating Characteristic; AUC: Area Under the Curve; IRT: Item Response Theory.

KEYWORDS:

• CRS-R
• CRS-R index
• CSR-R modified score
• disorders of consciousness
• unresponsive wakefulness syndrome
• minimally conscious state

Acknowledgments

We are highly grateful to the members of the Liège Coma Science Group and Centre du Cerveau² for their assistance in clinical evaluations. We thank all the patients and their families and the Neurology department of the University hospital of Liège.

Declaration of Interest

The authors report no conflicts of interest.

Additional information

Funding

This project has received funding from the University and University Hospital of Liège, the Belgian National Fund for Scientific Research (F.R.S-FNRS), the European Union’s Horizon 2020 Framework Programme for Research and Innovation under the Specific Grant Agreement No. 785907 (Human Brain Project SGA2), the Luminous project (EU-H2020-fetopenga686764), the Center-TBI project (FP7-HEALTH- 602150), the public utility foundation ‘Université Européenne du Travail’, “Fondazione Europea di Ricerca Biomedica”, the Bial Foundation, the Mind Science Foundation and the European Commission, the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778234, European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) for their support in the framework of the PRODEX Programme. CC is a post-doctoral Marie Skłodowska-Curie fellow (H2020-MSCA-IF-2016-ADOC-752686). CA and LRDS are research fellow, and AT are post-doctoral fellow, and SL is research director at the F.R.S.-FNRS Belgian National Fund for Scientific Research;.