In the case of Re M, summarised in the paper by Julian Sheather, Justice Baker faced the difficult task of weighing up objectively whether or not it was in Mâs best interests to withdraw artificial feeding and to let her die.1 The judge concluded that M was ârecognisably aliveâ, and that the advantages of continued life outweighed the disadvantages. He compared her minimally conscious state (MCS) favourably to that of a persistent vegetative state (PVS).2 It was clear that artificial feeding would have been withdrawn if she had been in a PVS (her family and physicians had thought for some time that she was in this condition), but because she was in fact minimally conscious, the judge decided that treatment must continue. But does it make sense to treat MCS differently from PVS in this way? Is it better to be minimally conscious than unconscious? Similar questions have been raised before.3 In 2006, scientists reported results of sophisticated neuroimaging studies which suggested that some patients in persistent vegetative state (PVS), long thought to be unaware, had evidence of minimal consciousness.4 The question then was on the moral significance of this level of consciousness, and whether the presence of such evidence meant that treatment such as artificial nutrition must be continued.5 ,6

There are several potential reasons why the presence of minimal consciousness might warrant continuing life-sustaining treatment. The first is that patients in minimally conscious state (MCS) might have a better prognosis than those who are in PVS. There are relatively few studies of long-term outcome in MCS, a condition that has been recognised and distinguished from other states of severe impairment only relatively recently.7 In one series, half of a group of 35 patients who had been diagnosed as being minimally conscious 1 month after a head injury developed signs of functional recovery by 12 months.8 In a French study, a third of patients who had been in MCS for more than a year showed some improvement over the next 5 years (while in the same study no patient in PVS improved).9 However, this improved outcome may not apply to all minimally conscious patients. The majority of patients who move out of the MCS do so in the first year after the onset of their illness or injury. Those who have a non-traumatic cause of their reduced conscious state have a much lower chance of improvement.8 ,9 Moreover, the degree of recovery may be limited. All 13 of the patients in the French series who recovered from MCS remained severely or totally disabled.9 In M's case for example (8 years after the start of her illness), it was accepted that the chance of her recovering significant function was remote (paragraph 47).2 This might mean that we should wait longer after the onset of MCS before making a decision about treatment (compared with PVS), but decisions might still eventually be made.

A second reason for continuing treatment in MCS is because of the possibility of the patient gaining some benefit from awareness of the surroundings and interaction with the environment. Justice Baker emphasised evidence that M had some awareness of herself and her environment, was able to respond to music, occasionally looked at those around her and had, on occasion, spoken discernible words (paragraph 174).2 But weighing against this, minimal levels of consciousness may also be associated with negative experience, including pain. Neuroimaging studies suggest that patients in MCS have patterns of brain activity in response to pain that are similar to fully conscious patients and considerably more extensive than patients in PVS.10 M was estimated to be in pain or discomfort 25%–30% of the time because of incontinence, spasticity or need for repositioning (paragraph 231).2 Furthermore, there is the possibility that the patient is at least intermittently aware of and distressed by his or her impaired state and inability to act or communicate, an experience that has been compared with indefinite solitary confinement.11 The question then becomes whether the intensity or duration of negative experiences for minimally conscious patients outweighs their positive experiences. In M's case, one expert and some of her family believed that it did, while her carers and another expert believed that it did not. In some cases of MCS, evidence of severe pain, or of genuine and meaningful pleasure, might give clear reasons to discontinue or to continue treatment. In other cases, as in M's, where there is disagreement and uncertainty about the nature of her experience, this appears to give no clear reason either in favour or against continued treatment.

Third, the fact that a patient is minimally conscious rather than in a vegetative state might give us an autonomy-based reason to continue or to withdraw treatment. One possibility is that sophisticated new technologies will allow patients who are minimally conscious to communicate their wishes.12 This might then allow them to indicate whether or not they are in pain, and whether or not they wish treatment to continue. However, to date, this sort of technology has not resulted in reliable communication for patients who are otherwise unable to indicate their wishes.12 Moreover, it appears that the so-called ‘covert cognition’ is present in only a subset of minimally conscious patients.13 In the only published series, none of the group of MCS patients with a non-traumatic brain injury (ie, similar to M) showed brain activity changes in response to a command.13

The other autonomy-based reason for continuing rather than discontinuing treatment would be on the basis of past wishes. For example, a patient might have previously indicated that he or she would like treatment continued in MCS but not in VS. However, it is also possible that someone would have regarded life in MCS as being worse than PVS.11 Or they may, as M's family claimed, have made no distinction between the two states regarding them both as highly undesirable.

Last, there is the possibility that distributive justice would provide a reason to treat MCS differently from PVS. Distributive justice is perhaps the most straightforward ground for limitation of life-prolonging treatment since it does not require an answer to the question of whether a person's life is overall worth living, but only an answer to a relative question of whether one life is more worth living or less expensive to support than another. For the first part of this equation, the above analysis suggests that MCS does not necessarily provide a greater benefit to the patient than PVS. For the second part, one estimate (now almost 15 years old) put the average lifetime cost of care for a patient with a severe traumatic brain injury at US$600 000 to $1.8 million.14 However, there is no reason to think that the long-term care costs of MCS are less than those of PVS. Even if it is of some benefit to be kept alive in an MCS (though we are sceptical of whether the benefits do outweigh the burdens), the magnitude of that benefit is small compared with other uses of limited health resources.

There are then no clear reasons for thinking that a state of minimal consciousness is necessarily better than a vegetative state. Prognosis, or limited awareness, or the wishes of the patient may in some cases mean that life-sustaining treatment should continue. However, in other cases, such as that of M, these same factors, together with distributive justice considerations, mean that treatment should stop.