The Glasgow Coma Scale is a quick and dirty way of determining impaired consciousness or presence of coma. It was introduced in a 1974 paper by G. Teasdale and B. Jennet in the journal Lancet, and has become accepted throughout the whole field of medicine, especially sport medicine. This test is meant to be given six or so hours after a closed head injury (concussion) of any kind, and scored according to the rubric below.

                  Eye Opening
Opens eyes on own                             4
Opens eyes when asked in loud voice           3
Opens eyes when pinched                       2
Does not open eyes                            1

                Motor Response

Follows spoken commands                       6
Can point to place where pinched              5
Pulls entire body part away when pinched      4
Flexes body inappropriately when pinched      3
Body becomes rigid when pinched               2
Has no response to pinch                      1

               Verbal Response

Converses well, knows who and where he is     5
Seems confused or disoriented                 4
Speaks words, but makes no sense              3
Produces unintelligible sounds                2
Makes no noise                                1

A total score is computed by adding the score in all three categories. A score of 15 indicates the person is entirely conscious and without serious brain injury, whereas a score of 3 indicates profound unconsciousness. Presence of a mild injury is indicated by a score of 13 or 14 points; a moderate injury by 9 through 12 points. 90% of patients with a score less than or equal to 8 after six hours will eventually enter a coma, and a score of 8 or fewer points after six hours indicates a roughly 50% chance of death due to brain injury. This scale's definition of coma is less rigorous than that of most medicine. Its three criteria are:

  1. Not opening eyes.
  2. Not obeying commands.
  3. Not uttering understandable words.