Glasgow Coma Scale (GCS) The Glasgow Coma Scale (GCS) is a neurological assessment tool used to evaluate a patient’s level of consciousness (LOC) in cases of head injury, coma, stroke, or critical illness. 1️⃣ Components of the Glasgow Coma Scale (GCS) GCS measures three parameters of consciousness: Component Maximum Score Minimum Score Eye Opening (E) 4 1 Verbal Response (V) 5 1 Motor Response (M) 6 1 Total GCS Score