Terri Schiavo has been in a persistent vegetative state since 1990. Her husband wants to withdraw the nutrition and hydration her body has been receiving and allow her body to die. Her mother, father, and sister—and now Florida Governor Jeb Bush—want to continue supplying her body with food and water until… what? She wakes up? Dies of pneumonia?
What is a persistent vegetative state? According to the National Institute for Neurological Disorders and Stroke people in PVS "have lost their thinking abilities and awareness of their surroundings, but retain non-cognitive function and normal sleep patterns. Even though those in a persistent vegetative state lose their higher brain functions, other key functions such as breathing and circulation remain relatively intact. Spontaneous movements may occur, and the eyes may open in response to external stimuli. They may even occasionally grimace, cry, or laugh. Although individuals in a persistent vegetative state may appear somewhat normal, they do not speak and they are unable to respond to commands." People suffering from PVS can generally be distinguished from afflicted but cognitively intact patients who suffer from "locked-in syndrome" by the fact that "locked in" patients can track visual stimuli and use eye blinks for communication.
According to most neurological experts, Terri Schiavo is definitely PVS—her eyes do not really track visual stimuli and she cannot communicate using eye blinks. However, Terri Schiavo's parents have posted several short ambiguous video clips online which are meant to show that Ms. Schiavo responds to stimuli. But what they show seems to fit an AMA's report of how PVS patients can respond to environmental cues without being aware. Specifically, the report notes, "Despite an 'alert demeanor', observation and examination repeatedly fail to demonstrate coherent speech, comprehension of the words of examiners or attendants, or any capacity to initiate or make consistently purposeful movements. Movements are largely confined to reflex withdrawals or posturing in response to noxious or other external stimuli. Since neither visual nor auditory signals require cortical integrity to stimulate brief orienting reflexes, some vegetative patients may turn the head or dart the eyes toward a noise or moving objects. However, PVS patients neither fixate upon nor consistently follow moving objects with the eyes, nor do they show other than startle responses to loud stimuli. They blink when air movements stimulate the cornea but not in the presence of visual threats per se."
Ms. Schiavo has been in this state for 13 years. What are her chances of recovering at least some awareness? Minnesota neurologist Ronald Cranford told the Washington Post, "There has never been a documented case of someone recovering after having been in a persistent vegetative state for more than 3 months. However, the journal Brain Injury reported the case, of a 26-year-old woman who, after being diagnosed as suffering from a persistent vegetative state for six months, recovered consciousness and, though severely disabled, is largely cognitively intact. However, it is generally agreed that if a patient doesn't become responsive before six months, his or her prognosis is extremely poor. A report on PVS by the Australian National Health and Medical Research Council finds that "patients in a state of post-coma unresponsiveness may emerge from it to become responsive," that "the probability of emergence becomes progressively less over time," and that "there is general agreement that emergence is less likely in older people, and in the victims of hypoxic brain damage." Terri Schiavo is the way she is because oxygen was cut off to her brain for 14 minutes; in other words, she suffered severe hypoxic brain damage.
So is Terri Schiavo still alive? The odds are way against it. It's time that her long-suffering parents and the grandstanding politicians let her go in peace.