Terri Schiavo, has been in a permanent vegetative state which is far more severe than a coma, since she had a heart attack in 1990 that deprived her brain of oxygen.
Under the medical definition, that became a permanent state after a month.Terri is now at the center of an emotional and political storm over whether she should be allowed to die; neurologists agree she will almost certainly never recover from her unconscious condition; no one has ever come back from such a condition, according to the American Academy of Neurology. The decision on whether and how long to keep such a patient alive is usually left to the individual doctor and the patient's guardian.
The Multi-Society Task Force on Persistent Vegetative State says in its 1995 guidelines that approximately 10,000 to 25,000 adults and 6,000 to 10,000 children in the United States are diagnosed as being in the persistent vegetative state, and survival beyond 10 years is unusual.
Terri's husband and legal guardian, Michael Schiavo, has fought to allow her to die and the courts have supported him. Last Friday the tube which keeps Terri alive was removed after Florida courts rejected numerous last-ditch legal attempts by the parents, Bob and Mary Schindler, to keep their daughter alive. But early in the hours of Monday morning President George W. Bush signed a bill allowing federal courts to again intervene in the matter.
The Schindlers believe their daughter responds to them and her condition could improve with treatment. Tennessee Sen. Bill Frist, a surgeon and Senate majority leader, has viewed videotapes and agrees with them.
But Dr. Ronald Cranford, a neurologist and bioethicist at the University of Minnesota Medical School, said reflexes can fool non-specialists and PVS patients often look fairly 'normal' to the families and loved ones, and to inexperienced health care professionals.
Such patients can even squeeze a hand in response to a caress, Swedish Covenant Hospital in Chicago says in guidance posted on its Internet Web site and sadly, these actions often appear meaningful to hopeful families but are all automatic reflexes - not movements with a purpose.
There are no confirmed reports of anyone fully recovering from a permanent vegetative state lasting more than three months.
In these patients, the cerebral cortex has been destroyed,"four to six minutes of anoxia, lack of oxygen, destroys that completely," said Dr. Lawrence Schneiderman, a physician and bioethicist at the University of California, San Diego. "The rest of your brain, particularly the brain stem, can survive for fifteen or twenty minutes without oxygen," added Schneiderman, who signed a friend of the court brief in July of last year supporting Michael Schiavo, but that part of the brain, the cerebral cortex, which is us, our personality, who we are, how we think - our capacity to experience, see, hear, think, emote - that may be permanently destroyed.
Experts say Terri Schiavo would experience no discomfort if allowed to die, as the part of her brain that experiences pain is unlikely to be functioning.