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Subject of the scale: Traumatic brain injury, coma, stroke

Glasgow Coma Scale


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The Glasgow Scale, or Glasgow score (Glasgow coma scale, GCS), is an indicator of the state of consciousness.

In an urgent situation, it allows the doctor to choose a strategy with a view to maintaining the vital functions.

This scale was developed by G. Teasdale and B. Jennet at the Institute of Neurology of Glasgow (Scotland) in 1974 for cranial traumatisms and was later used for several other pathologies (AVC, cardio-respiratory failure, septic shock).

This score is also often linked to the gravity (stratification of the risk of complications and spontaneous evolution) of comas.

It is often used to classify the gravity of a coma following an encephalic lesion:

> 13 = slight cranial traumatism

9 - 12 = moderate cranial traumatism

< 8 = severe cranial traumatism

> Access to the scale is free

Psychometric properties:


Psychometric properties



Face validity


Content validity


Criterion validity

Concurrent validity


Predictive validity

[3] [4] [7] [10]

Construct validity

Convergent validity


Divergent validity


Discriminant validity
(sensitivity and distinctiveness)



Intra-rater reliability


Inter-rater reliability

[5] [6] [7] [8] [9]



Internal consistency (alpha)




General comment on reliability:

The GC is one of the most used scales in the world of reanimation. Even though widely disseminated, several learned societies have reservations on its validity as much for taking a therapeutic approach (like orotracheal intubation) as for its prognostic value. This said, its ease of use and the great number of articles using this tool have made it one of the most essential scales, especially for brain-damaged patients.

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For more details of the scale, the comments or the psychometric properties presented here, please contact Dr. François GENET :


Inaugural references:

[1] Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet. 1974 Jul 13;2(7872):81-4.

Psychometric references:

[2] Amirjamshidi A, Abouzari M, et al. (2007). "Glasgow Coma Scale on admission is correlated with postoperative Glasgow Outcome Scale in chronic subdural hematoma." J Clin Neurosci. 2007 Dec;14(12):1240-1. Epub 2007 Mar 26.

[3] Balestreri M, Czosnyka M, et al. (2004). "Predictive value of Glasgow Coma Scale after brain trauma: change in trend over the past ten years." J Neurol Neurosurg Psychiatry. 2004 Jan;75(1):161-2.

[4] Chamoun RB, Robertson CS, Gopinath SP, et al. (2009). "Outcome in patients with blunt head trauma and a Glasgow Coma Scale score of 3 at presentation." J Neurosurg. 2009 Oct;111(4):683-7. doi: 10.3171/2009.2.JNS08817.

[5] Fischer M, Ruegg S, et al. (2010). "Inter-rater reliability of the Full Outline of UnResponsiveness score and the Glasgow Coma Scale in critically ill patients: a prospective observational study." Crit Care. 2010;14(2):R64. doi: 10.1186/cc8963. Epub 2010 Apr 14.

[6] Gill MR, Reiley DG, Green SM. "Interrater reliability of Glasgow Coma Scale scores in the emergency department." Ann Emerg Med. 2004 Feb;43(2):215-23.

[7] Iyer VN, Mandrekar JN, Danielson RD, Zubkov AY, Elmer JL, Wijdicks EF. Validity of the FOUR score coma scale in the medical intensive care unit. Mayo Clin Proc. 2009 Aug;84(8):694-701. doi: 10.1016/S0025-6196(11)60519-3.

[8] Kerby JD, MacLennan PA, Burton JN, McGwin G Jr, Rue LW 3rd. Agreement between prehospital and emergency department glasgow coma scores. J Trauma. 2007 Nov;63(5):1026-31.

[9] Menegazzi JJ, Davis EA, Sucov AN, Paris PM. Reliability of the Glasgow Coma Scale when used by emergency physicians and paramedics. J Trauma. 1993 Jan;34(1):46-8.

[10] Ting HW, Chen MS, Hsieh YC, Chan CL. "Good mortality prediction by Glasgow Coma Scale for neurosurgical patients." Journal of the Chinese Medical Association 73(3): 139-143.

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