A person in a vegetative state is defined as arousable- which means that they can have reflex responses to stimulus- but unaware. It is not necessary to wake up to be aroused. Patients in a persistent vegetative state's higher levels of their brain are no longer functional. Once a vegetative state exists from six weeks to three months, it is deemed persistent. The picture of the brain is a patients brain before and after PVS.
In many cases, the cerebral cortex of the PVS patient has died from major trauma or dementia. The brain stem, however, is alive. The stem controls cycles of breathing and awakefulness, making the patient appear as though he/she is alert. A brain scan shows that there is no activity that we normally associate with being awake. Even their eyes move, like in the cases of tracking a moving object. They can no longer feel hunger or pain, although they will appear to react to pain in a reflexive way.
Persistent vegetative state is different from a coma, because the cause of a coma is generally corrected and the patient begins to recover brain function. The coma is usually reversed within a few days. A person in a coma is unconscious, and therefore will not react like a person in a PVS would to stimulus. Since PVS is the late stage outcome of an irreversible coma or dementia, the outlook for recovery is almost always poor.When death of large areas of the brain occur, the outcome is generally grim and brain tissue does not regenerate. Many people recover fully from comas, but there are only five cases of recovery of some sort of function from people who have been in PVS.
Unlike brain death, people in persistent vegetative state are technically not legally dead. They are kept alive through feeding tubes and other assistive machines. Since people with PVS are unable to make decisions for themselves, a surrogate usually makes legal decisions for them such as whether to continue with medical treatment or being taken off (resulting in death). This is where legal cases come up regarding PVS, the most notable being the case of Terri Schiavo.
In 1990, Terri suffered a heart attack as a result of an eating disorder that sent her in to a coma. Although she came out of the coma, she came out with brain damage that left her in PVS. When brain scans were taken, they indicated no apparent functioning of the cerebral cortex. After three years of years of trying different methods, her husband decided that Terri would not want to live
Since a patient in persistent vegetative state appear to be alert, many (especially religious groups) consider it inhumane to take the patient off of life support because they might "recover"- as in the case of Ms. Schiavo's parents. Some patients are misdiagnosed, as in a recent study by the American Academy of Neurology that found that 18 out of 49 patients (37%) who had been given the label of PVS were truly not in this state. Those truly in the state, (again as in the case of Terri), however, have no hope for recovery of higher brain function.
like this and wanted to take her off of life support. Her parents, however, disagreed believing that Terri would someday miraculously recover. The case went to courts beginning in 1994. Eventually, in 2001, a Florida trial court ruled that Terri would not want to live on life support, based on "clear and convicting evidence" presented by some of her doctors and her husband. Legal battles continued. In 2003, when Terri's tube was removed for a second time, the Florida legislature came up with "Terri's law" to override the court decision, and the tube was reinserted. Finally, on March 18th, 2005 Terri's tube was removed for a third time. The U.S. Congress passed an emergency measure (which President Bush signed) to force federal courts to review Terri's case and create a legal mandate to have her tube reinserted. The U.S. District Court in Florida denied the appeal, and Terri died on March 31, 2005.
So what do you think- should persistent vegetative state patients be taken off of life support, or should a family keep them on in the rare case that they have been misdiagnosed and have a chance for recovery of brain function?