The Glasgow Coma Scale: How to Measure Unconsciousness

Not many years ago, in the world of medicine and psychology, there were many problems when it comes to identify signs of altered level of consciousness (in early stages) of thousands of patients around the world, so in many cases there were failures in the diagnoses, thus triggering negative consequences, since the treatment that was carried out in the same way did not it was correct.

There was also no general consensus on what a “serious” head injury entailed., and in different medical parts there were different subjective terms and medical notes that were not entirely clear: mild coma, deep coma, semi coma; "You are more aware today", and so on.

Fortunately, all that has changed, as there is currently a recognized scale at the level that allows a very precise and objective assessment of the level of consciousness of a patient. This is the Glasgow Coma Scale.

• Related article: "The 6 levels of loss of consciousness and associated disorders"

Features of this tool 

The Glasgow Coma Scale was created at the University of Glasgow in 1974 by English neurosurgeons Bryan Jennett and Graham Teasdale. This tool, in general terms,

allows to assess the severity of the coma and assess the state of consciousness of the person through tests that are carried out, which revolve around 3 axes: ocular response, motor response and verbal response.

On the other hand, this scale punctually evaluates two aspects:

1. The cognitive state

It is studied the level of understanding the person may haveThis is through compliance or non-compliance with the orders that the evaluator asks the evaluated person to carry out.

2. Alertness

The degree to which the person is aware is evaluated of the environment that surrounds him.

Advantages of the Glasgow coma scale

This instrument has the properties of discrimination, evaluation and prediction, something that no other similar instrument has to date.

• Discrimination: thanks to the scale, it is known which treatment is the most indicated for the patient, depending on the type and severity of the injury (mild, moderate, etc.).
• Evaluation: in the same way, it allows to evaluate the progress, stagnation and even decrease that the patient has (This can be observed by the application and qualification of the scale repeatedly time later).
• Prediction: it also manages to estimate a prognosis on the level of recovery that can be expected at the end of treatment.

Regarding the poor prognosis, the score obtained from this instrument, and the duration of the coma, represent two very important measures to consider in order to be able to determine the risk of cognitive impairment that may exist. The probability of death increases in the following cases: comas lasting more than 6 hours, in people of advanced ages, and with scores less than 8 (can be obtained from three to fifteen points).

• You may be interested: "What is brain death? Is it irreversible?"

Common mistake in its application and interpretation

There are cases in which the limitations of the patient are not taken into account at the time of evaluation. Sometimes the verbal response is valued when the person encounters an obstruction in the airway (tracheostomy or endotracheal intubation, for example). It would be a mistake then to apply it to that person, since obviously he or she will not be fit.

Another mistake, and that goes in the same direction as the previous one, is to assess the motor response when the person is sedated or you have a neuromuscular blocker in your body.

What is appropriate in these cases is not to evaluate him / her with a specific digit, but rather to register as "not assessable", because if it is applied and qualified as if impediments, there is the possibility that the medical report leaves the impression that the situation is very serious, since there would be a record of 1 point in that area, being that perhaps The evaluated person was able to obtain the 5 points, but not at the time that it was applied, just from what we have already seen, there was an object that did not allow him to perform in the test of the best possible way; They were limitations unrelated to something neurological related, and you should continue with the subscales that can be assessed.

Basic characteristics

The Glasgow Coma Scale has two invaluable aspects that have given it the opportunity to be the most widely used instrument in various medical units to make assessments of the level of consciousness:

Simplicity

Being an easy-to-use instrument, communication between different health professionals (even people who were not specialists in the subject, such as such as nurses, paramedics, etc.) improved greatly, since the understanding between the parties was much greater, since they all had “the same channel” of communication.

Objectivity

Using a numerical scale leave aside any assessment that may be considered subjective, here there is no room for different interpretations to be presented by different evaluators; in this case, it is rather to say if it presents the ocular-verbal-motor movement, or not, adding points or having a point in that area.

Bibliographic references:

• Antonio, P. P. (2010). Introduction to neuropsychology. Madrid: McGraw-Hill.

• Muñana-Rodríguez, J. E., & Ramírez-Elías, A. (2014). Glasgow Coma Scale: Origin, Analysis, and Appropriate Use. University Nursing, 11 (1), 24-35.