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

Systematic assessments of different methods in large numbers of patients in the Glasgow pointed to the merits of a multidimensional approach to assessment.

A shortlist 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, the position of the scale was reviewed in The Lancet Neurology (access the full text here). This reported the results of a survey that showed that the GCS is in use by neurosurgeons and other disciplines in more than 80 countries worldwide and has 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.

Key references

Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet 1974; 2:81-4.
Access the full text here

Teasdale G, Knill-Jones R, van der Sande J. Observer variability in assessing impaired consciousness and coma. J Neurol Neurosurg Psychiatry 1978;41:603-10.

Teasdale GM, Jennett B. Assessment and prognosis of coma after head injury. Acta Neurochirurgica. 1976 34: 45-53

Teasdale G, Jennett B, Murray L, Murray G. Glasgow coma scale: to sum or not to sum. Lancet. 1983; 2:678

Teasdale GM, Murray L. Revisiting the Glasgow Coma Scale and Coma Score. Intensive Care Med. 2000; 26:153-4.

Ponce FA, Lozano AM. “Erratum: Highly cited works in neurosurgery. Part II: the citation classics.” J Neurosurg 2014; 120:1252–57.

Middleton PM. Practical use of the Glasgow Coma Scale; a comprehensive narrative review of GCS methodology. Australas Emerg Nurs J. 2012; 15:170–183.

Graham Teasdale, Andrew Maas, Fiona Lecky, Geoffrey Manley, Nino Stocchetti, Gordon Murray. The Glasgow Coma Scale at 40 years: standing the test of time. The Lancet Neurology 2014; 13: 844 - 54
Access the full text here

Reith F, Brennan P, Maas AIR, Teasdale GM. Lack of standardization in applying painful stimuli for assessment the GCS. J. Neurotrauma 2014, in press.

Reith FCM, Brennan PM, Maas AIR, Teasdale GM. Lack of standardization in the use of the Glasgow Coma Scale. Results of international surveys. In Press

Teasdale G. Acute impairment of brain function-1. Assessing 'conscious level'. Nursing Times. 1975; 71: 914-7

Teasdale G. Galbraith S. Clarke K. Acute impairment of brain function-2. Observation record chart. Nursing Times. 1975; 71: 972-3

Teasdale G, Allen D, Brennan P, McElhinney E, Mackinnon L. The Glasgow Coma Scale: an update after 40 years. Nursing Times 2014; 110: 12-16