1. Glasgow Coma Scale

2. Glasgow Coma Scale or GCS is a neurological scale that aims to give a reliable, objective way of recording the conscious state of a person for initial as well as subsequent assessment.
A patient is assessed against the criteria of the scale, and the resulting points give a patient score between 3 (indicating deep unconsciousness) and either 14 (original scale) or 15 (the more widely used modified or revised scale).

3. Glasgow Coma Scale
The test measures the motor response, verbal response and eye opening response with these values

4. I. Motor Response
6 - Obeys commands fully 5 - Localizes to noxious stimuli 4 - Withdraws from noxious stimuli 3 - Abnormal flexion, i.e. decorticate posturing 2 - Extensor response, i.e. decerebrate posturing 1 - No response

5. II. Verbal Response
5 - Alert and Oriented 4 - Confused, yet coherent, speech 3 - Inappropriate words and jumbled phrases consisting of words 2 - Incomprehensible sounds 1 - No sounds

6. III. Eye Opening
4 - Spontaneous eye opening 3 - Eyes open to speech 2 - Eyes open to pain 1 - No eye opening

7. The final score is determined by adding the values of I+II+III.
This number helps medical practioners categorize the four possible levels for survival, with a lower number indicating a more severe injury and a poorer prognosis:

8. Mild (13-15):
More in-depth discussion on the Mild TBI Symptoms page.

9. Moderate Disability (9-12):
Loss of consciousness greater than 30 minutes
Physical or cognitive impairments which may or may not resolve
Benefit from Rehabilitation

10. Severe Disability (3-8):
Coma: unconscious state.  No meaningful response, no voluntary activities

11. Vegetative State (Less Than 3):
Sleep wake cycles
Arousal, but no interaction with environment
No localized response to pain
A persistent vegetative state is a condition of patients with severe brain damage who were in a coma, but then progressed to a state of wakefulness without detectable awareness. It is a diagnosis of some uncertainty in that it deals with a syndrome. After four weeks in a Vegetative State (VS), the patient is classified as in a Persistent Vegetative State. This diagnosis is classified as a Permanent Vegetative State (PVS) after approximately 1 year of being in a Persistent Vegetative State.

12. Persistent Vegetative State:
Vegetative state lasting longer than one month

13. Brain Death: No brain function
Specific criteria needed for making this diagnosis
Brain death is a legal indicator of death in the USA that refers to the irreversible end of all brain activity (including involuntary activity necessary to sustain life) due to total necrosis of the cerebral neurons following loss of blood flow and oxygenation. Brain-stem death (not whole brain death) is taken to be the significant indicator of death. The significant point is that the brain is no longer capable of sustaining the rest of the body's systems without advanced life support. It should not be confused with a persistent vegetative state. The concept of brain death emerged in the 1960s, as the ability to resuscitate individuals and mechanically keep the heart and lungs functioning became prevalent.
A brain-dead individual has no clinical evidence of brain function upon physical examination. This includes no response to pain and no cranial nerve reflexes. Reflexes include pupillary response (fixed pupils), oculocephalic reflex, corneal reflex, no response to the caloric reflex test and no spontaneous respirations.

14. Injury to specific areas of the brain will cause certain symptoms.
  For example, injury to the frontal lobes will cause loss of higher cognitive functions, such as loss of inhibitions leading to inappropriate social behavior.  Injury to the cerebellum will cause loss of coordination and balance.  The brainstem controls things like breathing and heart rate, as well as arousal.  An injury to this area could inhibit any of these processes.

15. GCS Modified to Age