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The reliability of the Glasgow Coma Scale: a systematic review

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Abstract

Introduction

The Glasgow Coma Scale (GCS) provides a structured method for assessment of the level of consciousness. Its derived sum score is applied in research and adopted in intensive care unit scoring systems. Controversy exists on the reliability of the GCS. The aim of this systematic review was to summarize evidence on the reliability of the GCS.

Methods

A literature search was undertaken in MEDLINE, EMBASE and CINAHL. Observational studies that assessed the reliability of the GCS, expressed by a statistical measure, were included. Methodological quality was evaluated with the consensus-based standards for the selection of health measurement instruments checklist and its influence on results considered. Reliability estimates were synthesized narratively.

Results

We identified 52 relevant studies that showed significant heterogeneity in the type of reliability estimates used, patients studied, setting and characteristics of observers. Methodological quality was good (n = 7), fair (n = 18) or poor (n = 27). In good quality studies, kappa values were ≥0.6 in 85 %, and all intraclass correlation coefficients indicated excellent reliability. Poor quality studies showed lower reliability estimates. Reliability for the GCS components was higher than for the sum score. Factors that may influence reliability include education and training, the level of consciousness and type of stimuli used.

Conclusions

Only 13 % of studies were of good quality and inconsistency in reported reliability estimates was found. Although the reliability was adequate in good quality studies, further improvement is desirable. From a methodological perspective, the quality of reliability studies needs to be improved. From a clinical perspective, a renewed focus on training/education and standardization of assessment is required.

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Acknowledgments

The authors would like to thank Sir Graham Teasdale, Emeritus Professor of Neurosurgery, University of Glasgow, UK, for the valuable discussions and very helpful contribution throughout the course of this work. This work was in part supported by the Framework 7 program of the European Union in the context of CENTER-TBI (Grant Number 602150-2).

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Authors and Affiliations

  1. Department of Neurosurgery, Antwerp University Hospital, Wilrijkstraat 10, 2650, Edegem, Belgium

    Florence C. M. Reith, Ruben Van den Brande & Andrew I. R. Maas

  2. University of Antwerp, Edegem, Belgium

    Florence C. M. Reith, Ruben Van den Brande & Andrew I. R. Maas

  3. Australian & New Zealand Intensive Care Research Centre (ANZIC-RC), School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia

    Anneliese Synnot

  4. Cochrane Consumers and Communication Review Group, Centre for Health Communication and Participation, School of Psychology and Public Health, La Trobe University, Melbourne, Australia

    Anneliese Synnot

  5. Central Clinical School, Monash University, Melbourne, Australia

    Russell Gruen

  6. Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore

    Russell Gruen

  7. ANZIC-RC, Department of Epidemiology and Preventive Medicine, Monash University, The Alfred Hospital, Level 6, 99 Commercial Road, Melbourne, VIC, 3004, Australia

    Anneliese Synnot

  8. Central Clinical School, Level 6, The Alfred Centre, 99 Commercial Road, Melbourne, VIC, 3004, Australia

    Russell Gruen

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  1. Florence C. M. Reith
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Correspondence to Florence C. M. Reith.

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Take-home message: The overall reliability of the GCS is adequate, but can be improved by a renewed focus on adequate training and standardization. The methodological quality of reliability studies should be improved.

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Reith, F.C.M., Van den Brande, R., Synnot, A. et al. The reliability of the Glasgow Coma Scale: a systematic review. Intensive Care Med 42, 3–15 (2016). https://doi.org/10.1007/s00134-015-4124-3

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