First, it helps to understand the basic functions of the brain:
Scientists believe consciousness depends on the constant transmission of chemical signals from the brainstem and thalamus to the cerebrum – neural pathways connect these areas and any interruptions to these messages can put a person into an altered state of consciousness.
The difference between a vegetative state and a coma? A vegetative state is a type of coma – a person is awake but in an unresponsive state of consciousness. A person can go into a vegetative state after being in a coma. The difference is, patients in vegetative state may still have low levels of consciousness. A comatose person is alive but is unable to respond to any stimuli or make any voluntary movement -> the brain is still functioning, just at it’s most basic level. We’ve all seen people in comas on the television, and more than often they come out and completely recover. However, coma survival rates are unfortunately not as frequent as the television may make them seem… coma survival rates are 50% or less, and less than 10% completely recover.
How do people go into comas? A person can become comatose when something causes the brain to swell. Consequently there is added pressure on the blood vessels. Blood flow to certain parts of the brain is blocked, causing a deprivation of oxygen. As we know, the brain cannot function without a consistent oxygen supply and this results in certain areas of brain dying.
The Glasgow Coma Scale (GCS) determines the degree of consciousness and impairment by adding up the scores from 3 sections: Eye Response, Best Verbal Response, Best Motor Response. The scores range from 3(very low – deepest coma) to 15(being normally awake and alert).
How do people come out of comas? There is no “cure” for a coma. Treatments can, however, prevent further physical and neurological damage. The speed at which a person comes out of a coma depends on the cause and how severely the brain is damages, just how the speed at which a person can become comatose can vary. One of the most important questions is, when a person is a coma in which they require a ventilator and feeding tube when do you decide to let the person die if they seem to have no hope?