What is the Glasgow Coma Scale?

The Scale was described in 1974 by Graham Teasdale and Bryan Jennett (Assessment of coma and impaired consciousness. A practical scale. Lancet 1974; 2:81-4.) as a way to communicate about the level of consciousness of patients with an acute brain injury.

The findings using the scale guide initial decision making and monitor trends in responsiveness that are important in signalling the need for new actions.

Eyes
  • Spontaneous
  • To sound
  • To pressure
  • None
Verbal
  • Orientated
  • Confused
  • Words
  • Sounds
  • None
Motor
  • Obey commands
  • Localising
  • Normal flexion
  • Abnormal flexion
  • Extension
  • None

Development

Comparisons of assessments of different methods in large numbers of patients in the Glasgow Neurosurgical Unit pointed to the merits of a multidimensional approach to assessment

A short list of terms capable of clear definition and grading in rank order was refined through studies of inter- observer agreement.

Refinement took account of input from junior doctors and nurses and from experienced international colleagues.

The aims in developing the scale were that it should be widely acceptable and should complement, not replace assessments of other neurological functions.

Adoption and spread

The Scale’s simplicity and ease of communication were welcomed in departments caring for patients with acute brain injury from trauma and other causes. Display of the findings on a specially designed chart facilitated detection of clinical changes. Nurses rapidly welcomed the clarity of capture of important trends in the condition of a patient.

With the rapid expansion in the numbers of intensive care units, the arrival of Computerized Tomography (CT) and the popularisation of brain monitoring there was a growth of interest in management of the head injured patient. Research required standardized methods for reporting initial severity and outcome. The Scale therefore became increasingly widely used as the common ‘language’ internationally to communicate about and debate the merits of the different advances in clinical practice and to apply them to caring for patients.

The use of Scale was promoted in 1980 when it was recommended for all types of injured person in the first edition of the Advanced Trauma and Life Support and again in 1988 when the World Federation of Neurosurgical Societies (WFNS) used it in its scale for for grading patients with a subarachnoid haemorrhage. The Scale progressively occupied a central role in clinical guidelines and an integral component of scoring systems for victims of trauma or critical illness.

Forty years after the original description, a review in The Lancet Neurology (2014; 13: 844 - 54) reported that the GCS was in use by neurosurgeons and other disciplines in more than 80 countries worldwide and had been translated into the national language in 74%. The review also noted a continuing rise in the use of the Scale in research reports, making it the most frequently quoted paper in clinical neurosurgery.

Derived Indices

The Glasgow Coma Scale Score (GCS score) was developed to combine the findings of the three components of the Scale into a single index. (Acta Neurochirurgica. 1979; 1: Suppl 28: 13-16). Its possible values range from 3 to 15. Although it lost some of the detail and discrimination conveyed by the full scale, it became popular as a simple summary measure in communication in clinical practice and in analysing and classifying findings in groups of patients.

The Glasgow Coma Scale – Pupils score (GCS-P) was described in 2018 in response to the wish for a single index combing the Coma scale with pupillary reactivity as a reflection of brainstem function (Journal of Neurosurgery 2018;128 : 1612-1620). It’s possible values range from 1 to 15, reflecting an extended range of severity, and may be particularly useful in relating to prognosis

Key references

Teasdale G, Jennett B: Assessment of coma and impaired consciousness: A practical scale. Lancet 304:81–84, 1974

Teasdale G, Galbraith S, Clarke K: Acute impairment of brain function-2. Observation record chart. Nurs Times 71:972–3e, 1975

Teasdale G, Jennett B: Assessment and prognosis of coma after head injury. Acta Neurochir (Wien) :1976

Teasdale G, Knill-Jones R, Van Der Sande J: Observer variability in assessing impaired consciousness and coma. J Neurol Neurosurg Psychiatry:1978

Teasdale G, Murray G, Parker L, Jennett B: Adding up the Glasgow Coma Score. Acta Neurochir Suppl (Wien) 28:13–6, 1979

Middleton PM: Practical use of the Glasgow Coma Scale; a comprehensive narrative review of GCS methodology. Australas Emerg Nurs J:2012

Teasdale G, Maas A, Lecky F, Manley G, Stocchetti N, Murray G: The Glasgow Coma Scale at 40 years: Standing the test of time. Lancet Neurol 13:844–854, 2014

Teasdale Graham, Allan D, Brennan P, McElhinney E, Mckinnon L: Forty years on: updating the Glasgow Coma Scale. Nurs Times 110:12–16, 2014

Ponce FA, Lozano AM: Erratum: Highly cited works in neurosurgery. Part II: the citation classics. J Neurosurg:2014

Reith FCM, Brennan PM, Maas AIR, Teasdale GM: Lack of standardization in the use of the glasgow coma scale: Results of international surveys. J Neurotrauma 33:2016

Reith FCM, Lingsma HF, Gabbe BJ, Lecky FE, Roberts I, Maas AIR: Differential effects of the Glasgow Coma Scale Score and its Components: An analysis of 54,069 patients with traumatic brain injury. Injury:2017
Access the full text (Accessed 18 July 2017)

Reith FC, Synnot A, van den Brande R, Gruen RL, Maas AI: Factors Influencing the Reliability of the Glasgow Coma Scale: A Systematic Review. Neurosurgery:2017

Reith FCM, Lingsma HF, Gabbe BJ, Lecky FE, Roberts I, Maas AIR: Differential effects of the Glasgow Coma Scale Score and its Components: An analysis of 54,069 patients with traumatic brain injury. Injury:2017
Access the full text (Accessed 18 July 2017)

Reith FC, Synnot A, van den Brande R, Gruen RL, Maas AI: Factors Influencing the Reliability of the Glasgow Coma Scale: A Systematic Review. Neurosurgery:2017

Brennan PM, Murray GD, Teasdale GM: Simplifying the use of prognostic information in traumatic brain injury. Part 1: The GCS-Pupils score: an extended index of clinical severity. J Neurosurg:2018

Murray GD, Brennan PM, Teasdale GM: Simplifying the use of prognostic information in traumatic brain injury. Part 2: Graphical presentation of probabilities. J Neurosurg:2018