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Glasgow Coma Scale (GCS)
The instrument is freely available here: Glasgow Coma Scale Link
NeuroRehab Supplemental - Highly Recommended:
Recommendations for Use: Indicated for studies requiring a physical/neurological examination. Recommended for Stroke studies.
Supplemental - Highly Recommended:  Stroke (based on study type, disease stage and disease type)
Short Description of Instrument
The Glasgow Coma Scale (GCS) was developed to overcome the misunderstandings and confusion about comatose patients. The GCS is also used to assess neurological trauma as well as to document and predict neurological changes. It is considered the gold standard in this regard and is widely used.
Comments/Special Instructions
The timing and frequency of assessment that are appropriate varies according to the stage after onset of the impairment of consciousness and the pattern in any previous observations of a patient. Observation should begin as soon as possible after onset of the impaired consciousness in order to guide initial management and to establish a baseline against which to interpret later findings. Observations initially should be repeated frequently to establish if the patient is stable or to detect any trends of improvement, or of deterioration from developing complications. When a stable pattern emerges as time passes, the frequency can be reduced.
The scale can be applied without modification to children over 5 years old. In younger children and infants, an assessment of a verbal response as "orientated" and motor response as "obeys commands" is usually not possible. A 'Paediatric Glasgow Coma Scale' was therefore described in the Adelaide Coma Scale in which responses were modified.
Scoring and Psychometric Properties
Scoring: Three questions must be answered in regards to unconsciousness and coma with the first addressing eye opening, the second motor function and the third verbal response. Scores range from 3-15 total points with lower scores indicating patients in comatose.
Psychometric Properties: Consistency in its findings is a key feature of a clinical assessment and during the development of the Glasgow Coma scale it was shown to be better than existing methods. Although some subsequent studies reported levels ranging from very poor to excellent a definitive systematic review has shown that the reproducibility of the scale is usually high.
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Baker M. Reviewing the application of the Glasgow Coma Scale: Does it have interrater reliability? J Neurosci Nurs. 2008;4(7):342-347.
Marmarou A, Lu J, Butcher I, McHugh GS, Murray GD, Steyerberg EW, Mushkudiani NA, Choi S, Maas AI. Prognostic value of the Glasgow Coma Scale and pupil reactivity in traumatic brain injury assessed pre-hospital and on enrollment: an IMPACT analysis. J Neurotrauma. 2007;24(2):270-280.
Reith FC, Van den Brande R, Synnot A, Gruen R, Maas AI. The reliability of the Glasgow Coma Scale: a systematic review. J Intensive Care Med. 2016;42(1):3-15.  
Sternbach GL. The Glasgow coma scale. J Emerg Med 2000;19(1):67-71.
Stocchetti N, Pagan F, Calappi E, Canavesi K, Beretta L, Citerio G, Cormio M, Colombo A. Inaccurate early assessment of neurological severity in head injury. J Neurotrauma. 2004;21(9):1131-1140.
Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale.  Lancet. 1974;2(7872):81-84.
Teasdale G, Knill-Jones R, van der Sande J. Observer variability in assessing impaired consciousness and coma. J Neurol Neurosurg Psychiatry. 1978;41(7):603-610.
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 2014;13(8), 844-854.
Weir CJ, Bradford AP, Lees KR. The prognostic value of the components of the Glasgow Coma Scale following acute stroke. QJM. 2003;96(1):67-74.
Document last updated January 2022