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This chapter evaluates the tenability of the unity thesis by examining the evidence for phenomenal disunity within the context of number of quite different domains. The first third of the chapter addresses the question of whether the unity of consciousness might break-down in the context of the perceptual phenomena of apparent motion and meta‐contrast masking. The second third of the chapter examines objections to the unity thesis that appeal to data derived from studies drawn from developmental psychology. The final third of the chapter evaluates objections to the unity thesis derived from a cluster of conditions that are characterized by minimal responsiveness: the persistent vegetative state, the minimally conscious state, and epileptic fugue states. It is argued that none of these objections undermines the unity thesis.

This chapter examines what we know and are learning about the permanent vegetative state and the minimally conscious state, as well as the new, promising techniques to distinguish between the two. It also reviews the evidence about Terri Schiavo's condition.

Recovery of consciousness following severe brain injuries typically evolves through several stages marked by considerable behavioral variability. This chapter considers the role of ‘circuit-level’ mechanisms in the forebrain in the generation of behavioral variability and specifically emphasizes the contributions of the central thalamus to altered arousal regulation in neurological disorders of consciousness. Neurons within the central thalamus play a key role in forebrain arousal regulation, acting as a nexus for the influence of ascending brainstem/basal forebrain neuronal populations (‘arousal systems’) and control signals descending from frontal cortical systems. Clinical distinctions among neurological disorders of consciousness and some observations of wide fluctuations in behavioral responsiveness in severely brain-injured patients can be organized by considering the possible role of circuit-level alterations of function involving the central thalamus, striatum and frontal cortical systems.

In this chapter, Hardcastle questions whether consciousness determines how much we should care about a living being. Instead of consciousness, Hardcastle focuses on pain and argues that consciousness is not required for pain. We do not know what it is like to be in a minimally conscious state, and misdiagnoses are numerous. For these reasons, it is reckless to assume that patients who have been diagnosed as being in a permanent vegetative state or a minimally conscious state lack pain or consciousness. That assumption could result in extreme and extended suffering, so we should assume that pain is possible and treat it.

This chapter reviews the diagnostic classification of disorders of consciousness, severe brain injuries that span a spectrum of brain states ranging from coma to the vegetative and minimally conscious states. The chapter makes the key point that brain states can – and do – evolve over time and that it is critical to be vigilant of changes that indicate that a patient who was unconscious is now conscious, albeit minimally so. The chapter describes how this traditional nosology is being challenged, and refined, by emergent technologies like neuroimaging and the ethical implications of this evolution for clinical practice and research. Specifically, the chapter addresses the challenge posed by discordant assessments when the clinical examination is brought into question by neuroimaging data that suggests that the patient is operating at a higher functional status than indicated by purely behavioral measures of assessment. Finally, drawing upon in-depth interviews of families touched by disorders of consciousness, the chapter explores family experiences and expectations, and suggests that these data indicates that the overriding goal of care, as understood by families, is the restitution of functional communication for this population silenced, at least in part, by disorders of consciousness.

This chapter considers the use of deep-brain stimulation as a treatment for neurological and psychiatric disorders. It addresses the question of whether a person with a disease of the mind can consent to stimulation of the brain, and how patients and medical teams weigh the potential benefits and risks of the treatment. It also describes some of the trade-offs between physical and psychological effects of stimulation. The medical and moral justification of this technique depends not only on whether it corrects brain dysfunction but also on how it affects all the psychological properties of the person.

This chapter explains and contrasts various scales that neurologists use to measure consciousness. These scales attempt to differentiate patients in a minimally conscious state from those in a vegetative state. They include the Glasgow Coma Scale, the Coma Recovery Scales, the Nociception Coma Scale, and the author’s own Coma Recovery Scale‒Revised. These scales are crucial for avoiding misdiagnosis and misunderstanding of patients with severe brain damage. Findings of studies on residual brain activity are described, with a focus on distinguishing conscious from unconscious states.

Hawkins sees the moral debates surrounding brain-damaged patients as coming down to two questions: whether the patients suffer and whether they derive benefit from their lives. In Hawkins’ view, life brings benefits only to those who have the capacities to form relationships and to value. Patients in permanent vegetative states and even minimally conscious states lack these capacities. For this reason, Hawkins defends the choice to allow such patients to die. In responding to the likely objection that such patients could express a desire to live, Hawkins questions the value of such messages on the basis that we cannot assess the quality of the decision making or the process behind it.

This chapter explains the values that conflict in choices of whether to let brain-damaged patients die. The author argues for the moral significance of consciousness, including not only phenomenal consciousness but also access consciousness, because it brings abilities. Nonetheless, other values, including autonomy and distributive justice, can conflict with the well-being of patients who have only minimal kinds of consciousness. These conflicts come to a head when a patient in such a state asks or previously asked to die. The considerations, as well as informational deficits at the time of the decision, are important to consider in regard to advance directives.

Disorders of consciousness are devastating to patients and present profound challenges to clinicians, scientists, philosophers, and ethicists alike. In the past, distinguishing between levels of these disorders has been vital to guiding important decisions. This chapter argues that these disorders are not sufficiently distinct, however, to dictate such decisions: diagnostic criteria are not discrete, nor do they reflect the conceptual definitions of these disorders. It argues that these non-distinct diagnostic boundaries reflect an inherent continuity between disorders of consciousness. In light of these points, a new way of thinking about disorders of consciousness is presented in the chapter to more effectively guide clinical decision-making. The chapter argues that these considerations bring clarity to disorders of consciousness and can improve the ethical management of patients suffering from these disorders.

In this chapter, modes of consciousness are distinguished from states of consciousness. A mode of consciousness is a global way of being conscious, such as waking, dreaming, seizures, and the minimally conscious state. States of consciousness are content specific, such as hearing music or feeling pain. Both modes and states of consciousness contrast with “levels of consciousness” in neurology. This original framework helps readers understand how the consciousness after brain damage is similar in some ways and different in other ways from normal consciousness.

This chapter examines issues of social justice as it pertains to the provision of health care for individuals suffering from profound neurological injury and brain death. Advances in neurology enable detection of the presence or absence of activity in different parts of the brain, allowing doctors to sustain the lives of patients whose neurological damage prevents consciousness. These advances have, in turn, raised questions about what sort of care is owed to such individuals, for how long, and why. The chapter first provides a medical background on coma, brain death, vegetative state, minimally conscious state, and locked-in state before discussing the social and ethical implications of sustaining a patient like Terri Schiavo, including the justice of abiding by or rejecting the values of people who do not accept the brain death standard. It also considers the role of efficacy in resource distribution.

This chapter summarizes the recently developed methods by which neuroscientists can detect consciousness in severely brain-damaged patients. These methods involve the use of functional magnetic resonance imaging or electroencephalography to discern willful brain activity in patients and healthy volunteers. Subjects are asked to use mental imagery of particular motor functions, and these can be used to indicate answers to “yes or no” questions. The authors discuss how far these methods can succeed in determining thoughts, intentions, feelings, and other mental states in patients who show no outward signs of consciousness as well as the diagnostic and judicial implications.

This chapter recounts the broad medical and cultural history of ideas about unconsciousness and the minimally conscious state. It provides a useful background concerning the various issues and beliefs about death and consciousness. Brain death and the vegetative state are discussed in detail. The chapter considers the hopes and fears of people from the last three centuries that provide the basis for current approaches. Examples include premature burials of live persons, respirators and iron lungs, modern ventilation, organ procurement, and withdrawal of food and fluids as a means of letting patients die.

This chapter first outlines a general framework for addressing ethical issues by applying Beauchamp and Childress’s principles of autonomy, beneficence, nonmaleficence, and justice. The authors then report the results of their survey of how laypeople rank these principles and reach overall judgments about whether patients with various disorders of consciousness should be allowed to die. The survey responses differ from those of physicians and bioethicists in fascinating ways. They also vary depending on whether the question is asked abstractly or concerns an actual concrete case and whether the question is about treatment withdrawal for other people or for themselves if they were in such a condition. The authors close by arguing that popular opinions about issues such as treatment withdrawal have indirect relevance to normative issues regarding what we should do.

This chapter introduce a healthy dose of skepticism about whether brain scans can prove any significant intentions, agency, or consciousness in brain-damaged patients. The authors argue that the abilities to follow commands and answer questions show only that these patients respond to external stimuli. They do not demonstrate that they have internally-originated intentions, much less plans, interests, or preferences about how life will proceed. Patients who pass these tests, they claim, still might have no more consciousness than patients with a different diagnosis: extreme akinetic mutism. They conclude that these tests do not demonstrate what is relevant to the moral status of being a person.

This chapter examines the clinical problem of detecting consciousness in brain-injured patients who emerge from coma in a state of behavioral unresponsiveness. Intensive care medicine is artificially producing, as a by-product of saving many lives, brains that may remain isolated, split, or fragmented. In extreme cases, large cortical islands or an archipelago of islands may survive totally dissociated from the world outside. Can these islands sustain consciousness? Does it feel like anything to be a big chunk of isolated human cortex? Scientific and philosophical doubts aside, we need to urgently address this question. The text underscores the necessity and difficulty of developing brain-based objective measures of consciousness, which are independent of sensory processing and motor behavior.

This chapter introduces key ethical and practical issues involving patients with disorders of consciousness and provides background information for readers who are new to these issues. It reviews the overall concept of the different states of consciousness in comparison with death. The relevant court cases and recent technological developments are described. This chapter launches the discussions that follow and provides a narrative that shows how the various chapters fit together.

The authors of this chapter address legal and policy issues surrounding guardianship of brain-damaged patients. Guardians assist patients in many ways and make many important decisions regarding treatment. Still, there is potential for infringing a patient’s civil liberties, especially when guardianship is assumed to be permanent. The authors argue that we need to structure guardianship so as to protect patients both while they are incompetent and also when they might regain competence. They also recommend that close family members be privileged in guardianship because they tend to have the greatest knowledge of and respect for the wishes of that individual patient.