The Neuroethics of Disorders of Consciousness

A Brief History of Evolving Ideas

Michael J. Young; Yelena G. Bodien; Joseph T. Giacino; Joseph J. Fins; Robert D. Truog; Leigh R. Hochberg; Brian L. Edlow


Brain. 2021;144(11):3291-3310. 

In This Article

Neuroethics in Disorders of Consciousness: A Road Map

Neuroethics is the ethics of neuroscience; that is, what is right and what is wrong in the evaluation or manipulation of the nervous system when conducting research or clinical care in the fields of the neurosciences.[5,13–20] In developing a systematic approach to neuroethics in DoC, it is worthwhile to consider issues as they pertain to and emerge from the principles of biomedical ethics. Questions of how to respect autonomy when the capacities that are prerequisite to autonomy are themselves disordered, as they are in DoC, are especially germane. This principle motivates inquiry into how to improve paradigms of consent, testing and counselling in this uniquely vulnerable and incapacitated population of patients. Considering the principles of beneficence and non-maleficence, questions relating to the perils of misdiagnosis and misprognostication arise. Additional challenges emerge relating to the ethics of brain–computer interfaces, covert consciousness (consciousness that is not detectable by bedside examination)[21,22] and disclosure of experimental data. The principle of justice prompts further inquiry into topics surrounding stigma of persons with DoC, equity in access to neurorehabilitation, integration of disability rights perspectives and law, fair distribution of limited resources and disparities in care.[5] Virtue ethics animates consideration of how to design systems and standards of research and care for the DoC population that instill the medical-professional ethos of integrity, compassion, accountability, prudence, trust, truthfulness and equity.[23–26] In addition to these principles, contemporary ethical inquiry is informed by analysis of prior instructive cases (casuistry), consideration of expected utility (consequentialism), analysis of normative obligations and duties (deontology), contractarian approaches, and clinical pragmatism.[27–31] Finally, there are a wide range of intriguing philosophical puzzles relevant to this field, relating to the proper classification of border-zone states of consciousness, the relationship of consciousness and personal identity, how to reconcile the subjectivity of consciousness with our conception of an objective reality and the relationship between neural processes and phenomenal experiences.[4,7,32,33]

At the core of cases in which neurologists are consulted for neuroprognostication in DoC are the fundamental questions of: is the patient conscious, if not, will that change, and if so, how can recovery be catalysed, and ultimately, what will the patient's life look like in the future? Therefore, a clear definition of the term consciousness is essential.

Before examining guideline-driven approaches to answering these questions, a particularly insightful comment found in the introduction of Plum and Posner's classic book on the Diagnosis of Stupor and Coma, where some of these diagnostic categories were initially defined, is worth mention. Plum and Posner remark that 'the limits of consciousness are hard to satisfactorily define, and we can only infer the self-awareness of others by their appearance and their acts'.[34]

These difficulties were foreshadowed by what is perhaps the first detailed medical treatise on the topic of DoC by Scottish physician and surgeon John Cheyne (1777–1836; eponymously associated with Cheyne-Stokes respirations) in 1812, entitled 'Cases of Apoplexy and Lethargy: With observations upon the comatose diseases'. In the prefatory remarks, Cheyne detailed that 'it is not my intension to offer any definition … I do not expect to succeed where great masters have failed … but as, in a medical treatise it is usual … I shall begin by presenting … some faithful sketches'.[35] Cheyne presciently later notes,

'I cannot be blind to the imperfect classification of the comata … such are the disease sometimes treated under the names of carus, cataphora, coma and lethargus … some of the best writers are not perfectly consistent in their application of these terms … had the genera of this order been less numerous, the subject would have been less embarrassed; for it appears, upon attentively considering the definition, descriptions, and histories and lethargus, or comatedes, and carus, that they differ not in nature but in intensity; that the same class of patients are affected by all these diseases, and that they flow from the same causes … there may exist cases concerning which we may be in doubt to which genus they ought to be referred'. [35]