Glasgow coma scale: definition

The GCS is the summation of scores for eye, verbal, and motor responses. The minimum score is a 3 which indicates deep coma or a brain-dead state. The maximum is 15 which indicates a fully awake patient (the original maximum was 14, but the score has since been modified).

For best eye responses, there are 4 possible scores:

• No eye opening
• Eye opening in response to pain. (i.e., pressure to fingernail bed or sternal rub)
• Eyes opening to speech
• Eyes opening spontaneously

For best verbal response, there are 5 possible scores:

• No verbal response
• Incomprehensible sounds (such as moaning)
• Inappropriate words
• Confused speech
• Oriented

For best motor response, there are 6 possible scores:

• No motor response
• Extension to pain
• Abnormal flexion to pain
• Withdrawal to pain
• Localizes to pain
• Obeys commands

Once the individual eye, verbal, and motor responses are summed, the final score indicates the following level of brain injury:

• Minor, GCS ≥ 13
• Moderate, GCS 9 – 12
• Severe, with GCS ≤ 8

There are also modifications to the score for intubated patients as well as pediatric patients, as their responses may not adequately grade their level of consciousness (i.e. a 6 month old cannot express themselves, nor can an intubated patient).