Prevalence of coma-recovery scale-revised signs of consciousness in patients in minimally conscious state

ABSTRACT

Different behavioural signs of consciousness can distinguish patients with an unresponsive wakefulness syndrome from patients in minimally conscious state (MCS). The Coma Recovery Scale-Revised (CRS-R) is the most sensitive scale to differentiate the different altered states of consciousness and eleven items detect the MCS. The aim of this study is to document the prevalence of these items. We analysed behavioural assessments of 282 patients diagnosed in MCS based on the CRS-R. Results showed that some items are particularly frequent among patients in MCS, namely fixation, visual pursuit, and reproducible movement to command, which were observed in more than 50% of patients. These responses were also the most probably observed items when the patients only showed one sign of consciousness. On the other hand, some items were rarely or never observed alone, e.g., object localisation (reaching), object manipulation, intelligible verbalisation, and object recognition. The results also showed that limiting the CRS-R assessment to the five most frequently observed items (i.e., fixation, visual pursuit, reproducible movement to command, automatic motor response and localisation to noxious stimulation) detected 99% of the patients in MCS. If clinicians have only limited time to assess patients with disorders of consciousness, we suggest to evaluate at least these five items of the CRS-R.

KEYWORDS:

• Coma recovery scale-revised
• minimally conscious state
• consciousness
• behavioural assessment
• severe brain injury

Acknowledgements

The authors thank the patients and their families, the University and University Hospital of Liège, the French Speaking Community Concerted Research Action (ARC 12/17/01), the Belgian National Funds for Scientific Research (FRS-FNRS), the Wallonie-Bruxelles International, the James McDonnell Foundation, Mind Science Foundation, IAP research network P7/06 of the Belgian Government (Belgian Science Policy), the European Commission, the Public Utility Foundation “Université Européenne du Travail,” “Fondazione Europea di Ricerca Biomedica,” the Bial Foundation, Human Brain Project (EU-H2020-fetflagship-hbp-sga1-ga720270), and Luminus project (EU-H2020-fetopen-ga686764). LH, OB, CM, CA are research fellows, OG, VCV, AT, AD are post-doctoral fellow and SL is research director at FRS-FNRS.

Disclosure statement

No potential conflict of interest was reported by the authors.