Glasgow coma scale is a practical method of measuring the person’s level of consciousness in response to different stimuli. The stimuli are divided into 3 categories: 1. Eye opening (divided into 4 grades) 2. Verbal response (further divided into 5 grades) 3. Motor response (divided into 6 grades) The score can range from 3 (minimum score seen in completely unresponsive patients) to 15 (completely responsive and normal). Brain injury can be classified according to the score as: Severe: GCS < 8 or 9 Moderate: GCS 9-12 Mild: GCS > 13