5-9. LEVELS OF HEAD INJURY

a. The Glasgow Coma Scale. The Glasgow Coma Scale (GCS) is the most widely used system of defining the level of consciousness of head-injured patients. Older classification systems relied on descriptive terms such as obtundation (diminished pain or touch sensations), stupor, semicoma, etc. These terms sometimes meant different signs/symptoms to different people. The Glasgow Coma Scale defines the level of consciousness according to three functions: eye-opening, language function (verbal response), and movement (motor response).

b. Responses of Glasgow Coma Scale. Each of these functions has a set of subscales made up of a hierarchy of responses which are assigned numerical values (points). The patient is stimulated, his response is observed, and a point value is given based on the response. The person examining the patient tries to draw out the best response from the patient. The total number of points from these patient responses defines a level of consciousness (recognized worldwide) and indicates the severity of the head injury.

c. Points Assigned Responses on the Glasgow Coma Scale. The points assigned patient responses are as follows:

(1) Eye opening. Examiner determines the best eye response in accordance with the following response grading scale:

(a) Eyes open spontaneously -- 4 points.

(b) Eyes open in response to speech -- 3 points. The patient opens his eyes when he is told to do so, or he responds to a command.

(c) Eyes open in response to noxious stimuli -- 2 points.

(d) Eyes do not open in response to noxious stimuli --1 point.

(2) Verbal response. Examiner determines the best verbal response in accordance with the following response grading scale:

(a) The patient is oriented to person, place, and time --5 points. The patient can talk and say who he is, where he is, the year, and the month.

(b) The patient is not oriented (is confused), but is able to communicate -- 4 points. The patient can talk but is somewhat confused.

(c) The patient speaks in a disorganized manner (inappropriate speech) -- 3 points. The patient does not enter into conversations but says understandable words (a curse, for example) or may say words which do not make sense.

(d) The patient responds with moaning or groaning sounds (incomprehensible sounds) -- 2 points. The patient vocalizes (makes sounds) but does not say recognizable words.

(e) The patient has no verbal response -- 1 point. The patient does not vocalize. He makes no sounds, nor does he respond to noxious stimulus.

(3) Motor response. Examiner determines the best motor response in accordance with the following response grading scale.

(a) The patient obeys commands appropriately and is able to move all extremities equally and spontaneously -- 6 points.

(b) The patient is still able to obey commands, but exhibits weakness (for example, drifting of an upper extremity) -- 5 points.

(c) The patient attempts to withdraw from the source of painful stimulus (flexor withdrawal) -- 4 points.

(d) The patient flexes an extremity abnormally -- 3 points.

(e) The patient extends an extremity abnormally -- 2 points.

(f) The patient has no motor response to painful stimuli (flaccid) -- 1 point.

NOTE: The Glasgow Coma Scale may not be valid in certain circumstances. The score of a patient who has used alcohol or other mind-altering drugs, is hypoglycemic, is in shock (systemic blood pressure less than 80 mm Hg), or who is hypothermic (body temperature below 34o C) may not accurately reflect the patient's level of consciousness.

d. Meaning of Total Points on Glasgow Coma Scale. The total points accumulated from the patient's responses indicate the following levels of consciousness:

Figure 5-1. Glasgow Coma Scale. (Abbreviated response scale)

(1) Comatose. Less than 8 points on the Glasgow Coma Scale.

(2) Moderate head injury. GCS total of 9 to 12 points.

(3) Mild head injury. A total point count of 13 to 15 on the Glasgow Coma Scale.