Disorders of consciousness (DOC), including the vegetative state/unresponsive wakefulness syndrome, and the minimally conscious state, have long fueled legal and ethical debate, and are also a source of considerable anguish for families forced to make life and death decisions on behalf of their loved ones. Particularly contentious are decisions concerning the withdrawal of life-sustaining treatment for patients who have a poor prognosis for further recovery. Implicit assumptions about the value of life in a state of impaired consciousness often inform decisions, but persistently unanswered questions about the quality of life of persons with DOCs remain a source of uncertainty and distress. Yet, despite the importance of quality of life in end-of-life decision making, there are no validated methods for assessing quality of life in this population. A significant obstacle to doing so is the inability of these patients to communicate.
Quality of life is inherently subjective, and while there are numerous instruments for assessing and quantifying quality of life in specific populations, most rely on patient self-report and self-assessment of the measured aspects of well-being. This presents particular challenges for assessing patients with brain injuries, who may have deficits in the ability to communicate, as well as in self-awareness and self-insight, all of which can impair self-reporting. Research on quality of life for persons living with brain injuries shows, however, that even the most profoundly disabled can confound expectations by reporting good quality of life, sometimes comparable to the well-being reported by healthy persons. Thus, there is reason to be cautious about relying on proxy informant reports of quality of life, or on the norms, preferences, and presuppositions of the general population. There is a danger that common and widely held assumptions are simply wrong about the subjective quality of life of persons with severe and disabling brain injuries. If they are wrong about the quality of life of brain-injured persons, they may be equally wrong about the quality of life of brain-injured persons with DOCs. Because quality of life has such a prominent place in beliefs about whether life is worth living for DOC patients, finding reliable and valid measures of quality of life in this population is a matter of the ethical urgency.
Recent neuroscientific advances, particularly in functional neuroimaging, might shed light on quality of life in DOCs. Indeed, there is propitious synergy between emerging neuroimaging paradigms that promise to enhance diagnosis and prognosis, and those that might objectively assess quality of life in DOCs, e.g. by examining such basic quality of life domains as the potential for pain and pleasure. Both improved diagnosis/prognosis and quality of life assessment would inform and enhance decisionmaking on behalf of DOC patients.
Quality of life research in DOCs would require an innovative, multidisciplinary approach and should consider both how and what to measure in persons with DOCs. To start, an alternative conception of quality of life, one sensitive to the functional status and interests of DOC patients is needed, because existing conceptions of subjective well-being, scaled to the norms and preferences of the general population would be inappropriate. Due to the low level of cognitive and physical functioning of DOC patients, they would always have an unacceptably poor quality of life on standard measures. It may, in fact, be true that their quality of life is unacceptably poor, but whether it is true remains an open question, and one that urgently needs answering.
Aside from the compelling need of decisional surrogates to have quality of life questions answered, what life is like for DOC patients is a critical piece of information about the potential burdens and benefits for them of treatment options. It is also needed to justify research because DOC patients are a highly vulnerable patient group, unable to consent to research participation. The success or failure of research into experimental treatments that might alter the cognitive or physical function of these persons—including such “halfway technologies” as deep brain stimulation and drug therapies (e.g. zolpidem)—cannot be adequately assessed without knowing how they affect the well-being of research participants. That requires being able to measure their quality of life both before and after experimental treatment. Just as it cannot be assumed that prolonging life is always a benefit to a DOC patient, it cannot be assumed that all changes of cognitive status, e.g. increased environmental or self-awareness, would necessarily enhance subjective well-being in patients who were previously shielded from potentially distressing truths by their condition.
Because we do not know what it is like to be in a state of severely disordered or diminished consciousness, we engage in a kind of substituted judgment, based on the values, desires, and interests we have as conscious persons capable of assessing our own well-being. We do that because decisions must be made for those who cannot speak for themselves, and as a practical matter, whether our beliefs and presuppositions are true or false cannot be verified. But there is an ethical imperative to know, to find out what can be known about the quality of life of persons with DOCs. If we make decisions based on false beliefs about quality of life for DOC patients, or about what constitutes an improvement or enhancement of their well-being, we deny these persons the tiny bit of self-rule, exercised through their surrogates, that remains to them.