pvs vs. mcs

with news that the US appeals court in atlanta has turned down a request by terri schiavo's parents for an emergency review of its earlier decision not to intervene, comes a report that the governor of florida, jeb bush, has suggested that doctors might have misdiagnosed schiavo's condition, which he says might be one of a minimally conscious state (MCS) rather than a persistent vegetative state (PVS). what's the difference?

well, i didn't know there was a difference until i read today an article from a site called neuroethics which drew a distinction between patients in PVS and those in MCS. it quoted a study published in 2003 which says that:

"In the persistent vegetative state, patients have lost cognitive neurological function but retain vegetative or noncognitive neurological function such as cardiac action, respiration, and maintenance of blood pressure… This state follows coma and is characterized by the absence of cognitive function or awareness if the environment, despite a preserved sleep-wake cycle. Spontaneous movements may occur and the eyes may open in response to external stimuli, but the patient does not speak or obey commands… The diagnosis of PVS should be made cautiously and only after extended periods of observation.

The term minimally conscious state [MCS] is distinguished from coma and persistent vegetative state by the preservation of discernible behavioral evidence of consciousness… The diagnosis is established by the presence of one or more of the following behaviors: (1) ability to follow simple commands, (2) gestural or verbal yes/no responses, (3) intelligible verbalization, or (4) purposeful behaviors that are contingent upon and relevant to the external environment."

in other words, patients in a MCS are more conscious compared with patients in a PVS. the article continues:

"The preponderance of medical opinion is that Terri Schiavo is in a PVS. However, based on her behavior; some have suggested that she is conscious. Although neither her brain damage nor her behavior are consistent with a locked-in state, in which patients are fully conscious, some observers would argue that they are consistent with a minimally conscious state. And most agree that the line between PVS and MCS is fuzzy."

what i have not heard discussed with any great detail and definitiveness is the opinion of her doctors and the actual state of schiavo's brain: namely, what tests have been administered on schiavo, has she undergone functional magnetic resonance imaging (fMRI), is her brain now irreversibly necratized (liquidized), and other hard medical facts such as those. maybe these facts are out there and i have missed them (in which case if i could be guided to those, i would appreciate it). i'd hate to have some politician (whoever he may be, governor or what-not), telling my doctors that their diagnosis has been wrong.

especially in a case such as this which has drawn the attention of the nation if not the world, the medical dimension of this sad situation should be made clearer and definite. sadly, in light of the article's words that "the line between PVS and MCS is fuzzy" this is perhaps one medical aspect which probably might never be made clear or definite.

read the article from neuroethics here.