A traumatic brain injury can affect a person’s level of consciousness. A complete loss of consciousness that endures for some time is considered a coma. However, a person may be conscious after a head injury but still suffer some impairment when it comes to the ability to speak, move, follow instructions or even open the eyes.
The Glasgow Coma Scale is an assessment used to discern the extent of impaired consciousness. It assigns point values to three different categories of responses that a traumatic brain injury may affect. The stronger and more functional the response, the higher the point value.
If a person is able to respond to commands to move, he or she receives a score of six points in the motor response category.
A person who is not able to respond to commands but withdraws from a painful stimulus receives either four or five points depending on whether the movement is instinctive or intentional.
If there is no response to either a painful stimulus or verbal commands to move, the person receives one point.
A person whose eyes are not open following a head injury and does not respond to stimuli intended to elicit an eye-opening response receives one point.
A person who opens his or her eyes only as a pain response receives two points.
Responding to a verbal command to open one’s eyes entails three points. If a person has his or her eyes open and is blinking, this response is worth four points.
This assesses whether a person is able to speak and correctly respond to questions about his or her situation. If the person’s speech is incomprehensible or he or she uses words that are inappropriate, the person receives two or three points, respectively.
A person who is able to speak intelligibly but appears confused about time, place or person receives four points.
A person who speaks intelligibly and demonstrates no confusion receives five points.
No verbal response receives one point.
Adding together the point values for the three categories produces the final score on the Glasgow Coma Scale. The lowest possible score is three, while the highest is 15. A GCS score of 13 to 15 indicates a mild head injury, while a score of eight or less is a severe head injury. The head injury is moderate if the GCS score is between nine and 12.