A coma is a "profound state of unconsciousness associated with depressed cerebral activity from which the individual cannot be aroused. Coma generally occurs when there is dysfunction or injury involving both cerebral hemispheres or the brain stem reticular formation."[1]
Unlike in coma, the eyes may be open in the persistent vegetative state.[2]
The FOUR (Full Outline of UnResponsiveness) score may be better than the Glasgow Coma Scale (GCS) among patients in critical care.[3] The FOUR Score tests: