Distinguish Patients in a Vegetative State from the Minimally Conscious state: moral and legal dilemmas
| Autor | Silvia Zullo |
| Cargo | Research Fellow in Bioethics at CIRSFID - School of Law of the University of Bologna. |
| Páginas | 13-27 |
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Current neuroimaging techniques -PET and functional MRI-have encouraged neurologists to have a closer look at vegetative patients’ clinical condition, exploring their residual cognitive abilities and their degree of awareness following serious brain injury. A recent example is Monti et al. (2010), who have attracted the attention of the scientific community for the findings they have reported in a study in which they asked questions to vegetative and minimally conscious patients and observed how the brain responds in these subjects in comparison with the brain response of conscious subjects: 5 responses were detected over a total of 54 subjects enrolled in the study, and in one case the response suggested a state of consciousness. Research in deep brain stimulation has shown that in some vegetative patients some areas of the brain remain active, making it possible to give voluntary behavioral responses to such stimulation, and in this way we can detect in these patients a transition from the vegetative state to the minimally conscious state.1
These diagnostic findings and advancements in neurology are compelling us to rethink the way we do diagnosis and prognosis for patients in a vegetative state (VS) or in a minimally conscious state (MCS), making it even more urgent to find a shared moral and legal basis on which to decide what treatments these patiens should undergo, especially as concerns the decision to end or prolong life support.
As is known, patients in a vegetative state present a peculiar clinical picture: we are dealing with persons who have come out of a coma and yet cannot seem to make any contact with their surroundings. And this impossibility, or at least the difficulty these persons have in establishing any such form of communication, makes it quite hard to determine how conscious they are of themselves and of the outside world: a state of consciousness does persist in these patients, but the standard clinical tests used to detect it do not take the peculiarity of this state into account, thus making such detection all the more difficult. This is a serious failing, considering that some "vegetative patients" do, after a time, give signs of recovery, appearing to resume contact with the environment and move into a "new" permanent clinical condition, namely, the minimally conscious state. As much as these signs may be intermittent and are not a sufficient basis on which to find that these patients are conscious of themselves or of their surroundings, they nonetheless have made it possible to distinguish the vegetative state from the minimally conscious state and to identify some previous diagnoses as incorrect.
These findings make all the more urgent the familiar moral and legal dilemmas arising in connection with persons in these "reduced" states, because in debating whether these persons have a will, we have to take into account the possibility that they may have "glimpses of consciousness," and
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this will make increasingly problematic the idea that we should always apply by default the principle In dubio pro vita in deciding whether to discontinue or prolong life support.
As is known, the VS condition cannot be classed as a "natural" end-of-life stage, for it is a new way of dying closely tied to recent biomedical advances. In addition, its diagnosis is probabilistic, nor is its prognosis any more certain. In 1972, Jennett and Plum observed a new clinical condition they described as neither a state of unconsciousness nor a coma in the ordinary sense of the term, but a state of wakefulness without consciousness (Jennett and Plum 1972). But this characterization of the VS has since been revised with the introduction of neuroimaging techniques, which have given us new findings that further complicate both diagnosis and prognosis for such patients. Further complicating the scene is the MCS that has since been described (Giacino et al. 2002), where vegetative patients who have suffered brain injury in time give signs suggesting that they are reestablishing contact with their environment (Defanti 2007).
As problematic as a prognosis of irreversibility is (for obvious moral reasons), even more complicated and difficult is a prognosis for the MCS, where the patient can satisfy simple requests and show intentional behavior (such as following an object with the eyes). As early as the late 1990s, the frequent misdiagnoses of the past prompted the scientific community (a group made up not only of neurologists but also of psychologists and philosophers) to call for more research into the way the VS is diagnosed: they were aiming to find a scientific basis on which to determine whether or not these patients still had a functional mind, and one concern they had was to ensure as far as possible that moral prescriptions and legal solutions could be framed without any ideological capture, which very much seems to be the trend now in the bioethical and legal debate, with the increasing tendency to envelop empirical data in value judgments.
And a further aim was to offer guidance to neurologists in diagnostic and therapeutic decision-making and supporting family members in deciding on a therapeutic course, in that a reliable diagnostic and prognostic basis can go a long way toward helping us make thoughtful decisions for ourselves and for others.
We are not yet in a position to tell whether the stimulus-and-response brain activity that can be detected using functional MRI with vegetative patients can be taken as evidence of anything more than a state of wakefulness. However, a 2006 study led by S. Laureys in Liège and A. M. Owen in Cambridge attracted a great deal of interest in the scientific community for its diagnostic use of this neuroimaging technology. The study (Owen et al. 2006) is similar to the one previously discussed (Monti et al. 2010, in which Owen also took part), in that the basic idea, here too, was to assign the same task to subjects in two different groups (healthy subjects, on the one hand; a vegetative patient, on the other) and use functional MRI to compare their brain activity. The task in this case was to imagine yourself playing tennis and then walking around your own home (30 seconds of sustained
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brain activity for each request): Owen observed that the vegetative patient (she had been in that condition for five months after traumatic brain injury) responded to the instructions through a cortical activation pattern similar to that of the volunteers in the healthy group: he drew the conclusion that she not only understood but also acted to carry out the instructions, and that this was evidence of an intention on her part. In the corroborating study of 2010, which Owen conducted with M. M. Monti in Oxford and Cambridge (Monti et al. 2010), 23 subjects involved were VS patients and 31 were MCS patients, and of the 5 corroborating responses-similar to the one observed in the vegetative patient in Owen et al. 2006-2 were in the VS group and 3 in the MCS group.2
To be sure, it is still too early to extract any definite normative conclusions from these findings, but in view of the rapid pace at which these functional imaging technologies are developing, we can see a future in which empirical findings will offer valuable support in making end-of-life decisions for and with patients in conditions we won’t be able to treat-patients we consequently won’t be able to bring back to a state of consciousness.
The most controversial of the questions to which the neurotechnologies are imparting a new sense of urgency are those involving the moral status of persons in a VS-at once patients and "moral agents"-and the way the law ought to regulate end-of-life decisions in these cases. Neuroimaging, in other words, is compelling us to think ever more carefully about the moral obligations we as a society have to persons in a VS or an MCS, and about the rights they ought to be recognized as having.
Discontinuing Life Support
The first case where a judge ruled in favour of discontinuing life support for a vegetative patient who had previously expressed a wish not be artificially kept alive in that condition, should it so happen, was in Massachusetts in 1986 (Paul Brophy), when it was decided to discontinue artificial provision of nutrition and hydration (ANH). And in 1991 (in the Helga Wanglie case) physicians and family members were arrayed on opposite sides, the former arguing against life support and the latter in favour, and the court came down on the side of the family, recognizing the woman’s husband as her rightful guardian, thus empowering him to make medical decisions in her best interest (Angell 1991).3
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Now accepted across much of the United States is the substituted judgment doctrine for deciding whether to withhold or maintain life-sustaining treatments for persons who did not clearly state their wishes before lapsing into a vegetative state: under this standard, a surrogate decision maker will try to make a decision based not so much on the patient’s best interest as on the patient’s own values and frame of reference, by taking into account any views the patient may have expressed as a healthy person about similar treatments and cases, as well as the patient’s moral, philosophical, or religious beliefs and outlook, so far as these can be reconstructed through a close acquaintance with the patient. From a clinical point of view, the American Academy of Neurology reaffirmed in 2006 the...
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