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

Ethical Challenges in Systems of Disorders of Consciousness Care

Having covered key nomenclature in this field, we will now turn to the challenges to current systems of DoC care. Many of the key ethical challenges that arise surrounding DoC involve high rates of misdiagnosis. Approximately 40% of patients diagnosed with vegetative state based on consensus opinion following bedside examination may be in the MCS, a finding that has been replicated across multiple studies.[135–140] Misdiagnosis can lead to dissonant consequences, especially in end-of-life decision-making.[141] Contrary to patients in vegetative state, those who are MCS retain some capacity for potential phenomenological experience, cognitive processing and pain perception.[142] Moreover, the prognosis of patients in MCS is significantly more favorable relative to those in vegetative state.[116,117,143–149]

Why are rates of misdiagnosis so high? There are at least 11 reasons.[5,62,150] These may be classified into patient factors, clinician factors and systems factors (Table 2).[101,151] Patient factors include sensory impairments, motor impairments, fluctuating responsiveness, comorbid conditions or medications that could mask a patient's underlying awareness or capacity to respond to a behavioural command. Clinician factors include evaluator inexperience, confirmation bias and resource utilization bias that may affect the ability of a clinician to rigorously and impartially administer neurobehavioural evaluations. Systems factors include complexity of consciousness assessment scales, training gaps, and prevailing diagnostic schemata that rely on the premise that absence of evidence of awareness should be taken as evidence of absence of awareness. Opportunities to address each of these factors and mitigate misdiagnosis should be recognized and strengthened. Such interventions may include improved education of clinical trainees for evaluating patients with DoC, further research and advocacy highlighting downstream ethical challenges resulting from misdiagnosis, all the way to systemic policy interventions, such as aligning incentives to allow for more time in clinicians' schedules for rigorous neurobehavioural examinations.

Existing nomenclature and diagnostic categories themselves can be conceptually problematic and may underpin the high rates of misdiagnosis. Some descriptions of vegetative state seem to define the syndrome anatomically, others behaviourally and others seemingly tautologically.[152] On the anatomical plane, despite early descriptions, there is wide variation in neuropathology and most do not exhibit loss of the entire neocortex but rather functional disconnection between key neuroanatomic regions. On the behavioural plane, the state of apparent unresponsiveness can be interpreted as unresponsiveness due to unawareness, unresponsiveness due to inattention, unresponsiveness due to impaired drive (e.g. akinetic mutism/abulia) or might reflect unresponsiveness due to covert consciousness.[153] Attempts at defining the syndrome in terms of consciousness itself become tautological.[152]

Accompanying shortcomings in misdiagnosis is undue pessimism. The rise of pessimism after brain injury coincided with the evolution of the right to die movement and concomitant over-generalization of nihilism to all forms of severe brain injury in the wake of Terri Schiavo and other prominent cases.[5,154] Most patients with acute DoC due to brain injury who die in the hospital do so in settings of the redirection of goals of care towards prioritizing comfort measures.[155–157] Such decisions to withdraw life-sustaining therapy are commonly predicated on expectations of poor recovery and cognate attributions of therapeutic futility.[158] Yet, in light of available data, it is not clear what drives these prognostic paradigms. In one cohort study of 50 patients admitted to a rehabilitation centre in vegetative state, 24% recovered responsiveness and 20% of the total sample recovered responsiveness at greater than 1 year (ranging from 14 to 28 months post-onset).[89] For patients in MCS, it is estimated that a third may emerge at greater than 1 year after coma onset.[145] In another study on the natural history of recovery from brain injury after prolonged DoC, 36 patients in a vegetative state or MCS were followed for 4 years during and after rehab. At 4 years, ~50% returned to daytime independence at home; 22% returned to work or school and 17% recovered to at or near pre-injury levels.[146] Considering the total sample, almost two of three patients admitted to acute or chronic rehabilitation settings in vegetative state recovered consciousness, many at time points beyond what former diagnostic guidelines would have dubbed permanent. One group recently found that functional outcomes of patients may continue to progress towards functional independence up to 10 years post-injury.[159] While by design these studies measured outcomes only in persons for whom life-sustaining treatments were continued and could not establish counterfactual outcomes for those where those treatments were withdrawn, the results appear at odds with typical poor prognoses and attributions of futility delivered to the families of patients with acute DoC.[159–162] Because it may be surmised that patients who survive to transfer to rehabilitation facilities may be the least medically and neurologically ill within their respective diagnostic categories, some suspect that prognoses for the patients followed in many neurorecovery studies may be better than for an average patient in an acute care environment with a given DoC. This underscores the need for further study of the natural history of recovery in contexts where withdrawal of life-sustaining treatment is uncommon regardless of perceived prognosis, as is now underway.[163–165] Prior evidence suggesting that factors other than injury severity play an equal or greater role in rehabilitation referral decisions (including involvement of family and a physiatrist in clinical care), together with limitations in data comparing outcomes in DoC patients referred versus not referred to inpatient rehabilitation, confound the attribution of uniform selection bias in rehab referral processes favoring patients with better prognoses.[166–170] Recent prospective, longitudinal evidence from a study of patients enrolled in the Traumatic Brain Injury Model Systems National Database did not suggest systematic severity-based referral bias.[171,172] These points underscore critical opportunities for further empirical investigation. Nonetheless, in light of data highlighting the possibility of meaningful recovery in a substantial percentage of patients, what drives decisions to limit treatment?

The Heavy Weight of Bias and the Limits of Certainty

Clinicians, especially those practicing in acute settings, tend to see this population of patients at their worst and often comatose states, which in many other contexts is a justifiable marker of terminal illness and a reasonable trigger for end-of-life discussions.[5,173] In contrast to practices in some regions,[174,175] clinicians in the USA and elsewhere are often trained to protect patients' dignity at the end of life by not unnecessarily prolonging the dying process and often believe that patient advocacy demands directing families to less aggressive care when death is apparently imminent.[158,176–178] However, in settings of acute DoC, reliable prediction of recovery is inordinately challenging.[179] Most clinicians caring for these patients during acute hospitalization do not bear witness to the clinical course of patient recovery during the neurorehabilitation phases, when care is directed by multidisciplinary teams including physiatrists, therapists and psychologists. Attributions of poor prognosis may thereby become self-fulfilling, wherein expectations of poor outcomes drive actions that engender this clinical reality.[156,180,181] In so doing, acts of prognostication slip from the descriptive to the performative, bringing about or transforming states of affairs that they ought only describe.[182] Such decisions therefore carry a high risk of promoting a self-fulfilling prophecy bias that is compounded by a fuzzy nosology and resource constraints that may force premature closure and solidified at times by an erroneous view of disordered consciousness as irreversible.[11]

Apart from self-fulfilling prophecy bias, a range of other cognitive biases weigh heavily on decision making in this population. The disability paradox refers to the fact that many who are living with disabilities report good or excellent quality of life despite external observers' attributions of suffering.[183–185] This paradox and its tendency to unduly influence clinical decision making has been described repeatedly in studies on patients in the locked in syndrome, spinal cord injury, stroke and other conditions, and may stem from a failure to understand how the prudential values or capacities for experience may change with disability.[186–188] The inability to assess quality of life in those who cannot respond, and the pliable, subjective nature of what constitutes a 'meaningful recovery', compounds the difficulty of clinical decision-making in these contexts.

More foundationally, clarity about the value of consciousness for patients and families is needed.[6,189] Whether the state of consciousness is viewed as intrinsically valuable or valuable instrumentally and only insofar as the experiences that it may instantiate will be uniquely influential in determining ethically appropriate and goal-concordant care for patients with DoC. Some theorists have contended that states of reduced consciousness preclude attribution of 'full moral status' or the experience of 'life worth living'.[190–192] While some limited data have been gathered,[193,194] these approaches require further phenomenological and empirical study, particularly including investigation of projected versus actual life satisfaction across a wider range of DoC states, determinants of quality of life and possible evolution over time in those who have improved.[195–200] This may be achieved by surveying the perspectives of patients, surrogates and others whose voices may provide a window through which the phenomenology and moral significance of these states could be empirically understood and rigorously grounded. This could foreseeably vary by culture, context or background.[201–203] Principles of justice and truth-telling support the imperative that clinicians describe such uncertainty with candor and transparency. Such counselling should aim to explain the range of best and worst possible interpretations and outcomes, instead of relying on synthetic or monotonic judgments, avoid disability bias and ensure that care delivered protects patient dignity and preferences to the extent that they may be ascertained.[154,204–206]

Implications for Clinician-family/Surrogate communication

While some portion of patients with DoC may make remarkable recoveries, a significant portion will not, despite months or even years of intensive rehabilitation and long-term care. Families of these patients may experience significant financial losses and psychosocial distress, and resources and support systems for family members caring for loved ones with DoC are limited. Some may turn to crowdfunding campaigns to continue aggressive treatments due to gaps in insurance coverage and exhausting all personal resources (a May 2021 search of the largest crowdfunding platform, GoFundMe, revealed over 400 campaigns for patients in a vegetative state or with unresponsive wakefulness syndrome or MCS; while many of these campaigns were USA-based, there were numerous campaigns to raise funds for patients in other regions around the world).[207] For some family members, there may be substantial opportunity costs, such as foregoing educational or professional opportunities because of the need to care for, and be available for, a recovering loved one. Also, for the patient, there is the potential pain, suffering and loss of dignity of continued treatments that ultimately prove to be non-beneficial or without attainment of what the patient would agree to be a minimally acceptable neurological outcome. How to balance these prospects for harm against potential benefits of continuing life-sustaining treatment requires careful ethical and empirical study. With every decision to continue aggressive therapy, surrogates should be counselled that these decisions need not be permanent, and that decisions surrounding goals of care could and should be revisited at regular intervals under the guidance of a clinician who may track relevant progress/stagnation, update prognostic expectations and counsel surrogate decision makers accordingly. Indeed, while counselling surrogate decision makers that a decision to transition to hospice care can be made at any time, clinicians should also recognize that making such a transition many months or years after acute injury is itself accompanied by complexity.

Often, decisions surrounding the intensity and goals of treatment converge on questions of nutritional management (e.g. tube feeding), pulmonary support (e.g. mechanical ventilation), treatment of comorbid medical conditions and management of symptoms or complications of brain injury (e.g. intracranial pressure, dysautonomia, seizures, spasticity and pain). To achieve goal-concordant care, clinicians must work closely with surrogate decision makers to provide education about these categories of management and explain possible treatment pathways (e.g. rehabilitation-focused or comfort/palliative-focused) along with the range of possible outcomes that might be expected through each treatment pathway, and they should diligently identify how patient values and preferences can help guide consistent decisions. While some treatment decisions may be reversible and time-insensitive, others are more critical and may shunt families and patients towards a particular treatment path.[208] Commonly, after several weeks of endotracheal intubation, clinicians become worried about the risk of tracheal erosion and thus a possibly premature pressure is placed on deciding whether to place a tracheostomy (commonly paired with a percutaneous gastrostomy tube). Placement of a tracheostomy for some patients will remove the requirement for mechanical ventilation. But with the course of recovery being easier to predict even a week later, the early forced decision may result in an extended life with DoC that the surrogate might have, a week later, ethically judged to have been more appropriately transitioned to comfort measures via palliative extubation.[209] The perceived limited window of opportunity for certain critical treatment decisions or early palliative care may amplify the psychosocial burden on surrogates faced with these decisions, especially when likely outcomes are uncertain.[210–212] Providing psychosocial support to surrogates through the decision-making process is therefore imperative.[213] Surrogates should be prospectively counselled that if eventual outcomes do not align with prior expectations, overall treatment goals may be revisited and revised as needed. Specialized systems of longitudinal care for patients with prolonged DoC may thus help to ensure alignment of treatment decisions with patient goals across the care continuum.[214]