What is the Glasgow coma scale?

Answer: The Glasgow coma scale is an assessment of a person’s consciousness level with a 3 being completely comatose and a 15 being fully awake.

glasgow coma scale

The Glasgow coma scale was first developed in 1974 by two neurosurgeons named Graham Teasdale and Bryan Jennett. It is used for assessing an adult’s consciousness after a traumatic head injury. Another way to think about it is that the scale measures the level of activity of the central nervous system.

The scale is only applicable for adults who are able to make appropriate responses. For infants who do not have complete responding, they will score poorly on the verbal component of the coma scale.

The Glasgow coma scale measures the responses of three components:


Eye response on the Glasgow coma scale is rated from 1 to 4, with higher numbers indicating increased awakeness / consciousness. For each symptom that a patient exhibits, add the number that best describes their response.

  1. Eyes do not open.

  2. The eyes only open in response to application of a painful stimulation.

  3. The eyes may open in response to a voice, without any physical touch.

  4. If the eyes are open in normal conditions. A fully conscious person would receive a 4 on this scale.


The verbal score on the Glasgow coma scale is a measure of a person’s ability to use language. These scores are ranked from 1 to 5, with 1 being most unconscious and 5 being awake.

  1. A patient does not make any sounds at all.

  2. The patient is able to make some sorts of sounds, not necessarily anything specific.

  3. If they patient is able to say words, but not complete phrases or sentences. Generally, incomplete thoughts may be given a 3.

  4. A patient produces speech that is confused or disoriented.

  5. Normal communication. People who are fully awake are able to respond completely in conversation.


The Glasgow coma scale also evaluates a person’s gross motor skills. Motor skill is rated on a scale from 1 to 6, and as with the other scales, lower numbers indicate lower central nervous system activity, whereas a higher score is indicative of increase consciousness.

  1. The person makes no movements whatsoever.

  2. A painful stimulus induces abnormal extension. This reaction is also called the decerebrate response.

  3. A painful stimulus causes unusual flexion. This reaction is also called a decorticate response.

  4. Painful stimuli causes withdrawal or an appropriate reflex.

  5. The patient is able to localize where the painful stimulus is applied.

  6. The patient can respond to and obey commands.

With the GCS, the sum of the numbers as well as the individual components are significant and are a useful diagnostic tool. Therefore, it is useful to record all the relevant scores for a patient.

Reading a Glasgow coma scale score

Lower than 9: This is a severe brain injury with coma like symptoms.

Between 8 and 12: This is a moderate brain injury

Greater than 13: Minor brain injury.

The scores may be difficult to interpret in the case of certain medical procedures such as an intubation, where a flexible plastic tube is put into the trachea in order to permit sustained airflow to allow the person to breathe. In this case, the Verbal score appears to be a one, even though the person may be fully capable of answering questions and forming complex sentences. In this case, you might see V1t as the verbal score (t=tube.) For these people, the top score they can achieve would be a 10.

Alternatively, another reason that a score may be difficult to interpret is in the case of facial injury, particularly to the eye. If the injury is severe enough, the eyes may be swollen shut, thus making it difficult to assess whether or not a person’s eyes are responsive to stimuli or not. Again, the GCS may be written under this condition as E1c (c=closed).

Another method by which a person’s consciousness can be rated is the Rancho Los Amigos Scale.