Issues in clinical neuroethics

Personhood and identity. The modern association of personhood and identity with the mind and brain distinguishes neuroethics from other subjects of bioethical inquiry (66; 63). Localizing the essential self to the brain, termed “brainhood,” has contributed to emphasis on neuroscientific research and underscored the necessity of neuroethics. For the purposes of this abbreviated introduction, we present the functional definition of personhood as the essential characteristic or set of characteristics that give an agent moral status. These attributes are typically intimately related to or dependent on cognitive capacities. However, diverse perspectives remain regarding the appropriateness of cognition as the seat of personhood (59; 64; 18; 10). Because of the intimate relationship between brain, mind, and identity, there are numerous reports of patients feeling or appearing fundamentally changed—seemingly a different person—after injury to or medical intervention with the brain, be it surgical or pharmacological (40; 08; 41; 37).

Neurodiversity and inclusivity. Because the brain is so intimately tied to identity, a social justice movement has challenged notions of which brains and their resultant identities are considered “normal” and socially acceptable. Neurodiversity explores how both society and the medical institution could recognize and accept the inherent differences in cognitive and neurologic functioning rather than treating or intervening with characteristic traits of individuals diagnosed with autism spectrum disorder, ADHD/ADD, and bipolarity (06). Neurodiversity advocates argue that by pathologizing neurologic diversity, neuroscience has unnecessarily medicalized natural developmental variance in human cognition (32; 34). To be clear, not all neurodiversity advocates suggest that having autism spectrum disorder, for example, is not distressing and does not require accommodations for these differences. Rather, advocates suggest that the core features of autism spectrum disorder are identity-forming, and patients may want assistance that works with rather than against their conditions to enable them to live fulfilling lives.

Notes on person-first language. Utilizing appropriate semantics for the person-disease relationship can be challenging in considered medical discourse and in the context of neurodiversity. Currently, debate persists about the use of person-first language (person with autism vs. autistic person) for neurologic and psychological conditions. It is important to remain cognizant of the order of words when speaking with or about patients, as many greatly value the distinction between person-first and condition-first language. Preferences tend to correlate with the individual’s understanding of identity—that is, whether the condition is integral to their person or something from which distance is sought (57).

Autonomy and agency. One of the rights engendered by personhood is respect for one’s autonomy, or one’s capacity for self-determination. One who can act autonomously (ie, able to demonstrate reasoning, deliberating, and independent choosing free from undue external influence) is considered an autonomous agent with decision-making capacity (17; 10). In Western biomedicine, the brain has become understood as the executor of all autonomous functions (62). In the clinical setting, autonomy most often manifests in acknowledging patients’ rights to decide which healthcare interventions they will and will not receive. In the future, the very nature of undue influence may change with developing neurotechnological capabilities to “read and write” the brain (42; 01).

Informed consent. Informed consent was developed to recognize the right to autonomous choice and protect patients and research subjects from harm (09). In research trials, informed consent is often problematic. Patients are requested to sign complicated documents that frequently fail to facilitate truly informed consent (29). To provide consent to a procedure, an individual must be deemed to have decision-making capacity or the cognitive ability to understand, make, and indicate a choice between alternatives. A surrogate may make choices for patients who have temporarily or permanently lost decision-making capacity. Acquired injury, neurodegeneration, or neurotechnological intervention can all impact an individual’s capacity to consent.

Informed decision-making requires effective communication of information such as the risks of proposed treatment, alternative options (including abstaining from treatment), as well as the opportunity to ask and receive answers to clarifying questions. However, enabling an informed decision becomes particularly complex in brain interventions that may unpredictably challenge the capacity to consent or even affect qualities and temperaments associated with identity. Challenges to traditional assumptions about capacity have grown from new developments in detecting covert awareness in patients thought to be in a vegetative or minimally conscious state, which will be discussed later in this article (22).

Clinical applications

The body of this article highlights important neuroethical issues that arise with neurologic disorders and interventions throughout the lifespan while also looking into issues likely to present in the near future. Some of these topics are familiar, whereas others are unprecedented, surfacing in tandem with neuroscientific innovation.

Acquired injury. With acquired injuries, such as stroke or traumatic brain injury, physicians and surrogates must contend with patients’ compromised capacity to make autonomous decisions due to cognitive dysfunction. For patients retaining consciousness, the capacity to make a decision is assessed based on the individual’s ability to (1) appreciate the current situation and the consequences of the decision, (2) understand treatment options and their outcomes, (3) engage in reasoning about the alternatives, and (4) communicate a decision (04). In cases of severe injury, determinations of capacity may be heavily influenced by the technology used for assessment. For example, imaging studies have indicated that some patients in the locked-in state or with disorders of consciousness may be able to indicate preferences by answering yes-no questions mediated by fMRI (44; 14). Capacity may further vary on a temporal basis and may exist for some choices but not others; the gravity of the decision often determines the degree to which one must demonstrate meaningful choice.

Diagnostic uncertainty has long been an inescapable challenge for neurologists identifying disorders of consciousness and may further complicate treatment decisions. However, developments in neuroimaging have increased the clinical ability to distinguish between the vegetative state and the minimally conscious state, enabling more accurate diagnoses and prognoses (23; 45). Currently, functional MRI and diffusion tensor imaging may together provide the most informative and accessible imaging techniques to distinguish between the vegetative state and the minimally conscious state (26). Although EEG is a powerful and practical tool for the assessment of brain function, it may not be prognostic after cardiac arrest. The TELSTAR trial showed that treating concerning EEG patterns after cardiac arrest did not alter outcomes (54). As neuroimaging technologies advance and understanding of neurologic correlates of consciousness increases, the ability to accurately diagnose and prognosticate for patients with disorders of consciousness will likely improve.

Following best efforts in diagnosis and prognostication, a plan of care must be elected. Although many understand the treatment options for patients with severe disorders of consciousness to be diametric extremes (ie, prolonged life-sustaining treatment with little hope of recovery or withdrawal of life-sustaining treatment leading to death), others have argued for the moral obligation to improve neurorehabilitation efforts and promote the use of neuroprosthetics for this population. Neuroprosthetic technologies like deep brain stimulation may restore functional communication—even if only to the level of assent—to patients with disorders of consciousness and enable them to participate in rehabilitation research and, one day, treatment decision-making (20; 23; 21).

End of life and brain death. Significant ethical challenges are brought about by deep and continuous sedation until death (46). This approach was codified into French law in 2016, and the concept has spread to other places. The French law is clear because it gives specific circumstances for application.

Brain death arose from the paradigmatic report “A Definition of Irreversible Coma” (Anonymous 1968) in response to advancements in resuscitation and critical care, the physiology of consciousness, and increasing concern about medically futile interventions (16). Debate continues as to whether brain death can be equated to biological death or whether perhaps the term serves more as a useful “legal fiction” to support organ donation, conserve costs on nonbeneficial treatment, or diminish suffering at the end stages of life (61). Even so, brain death is legally recognized in all 50 U.S. states as equivalent to death determined by cardiorespiratory criteria. Because the term “brain death” itself may be problematic in its implication that there is more than one kind of death, “death by neurologic criteria” should be used (49). Determination of death by neurologic criteria requires known occurrence of acute and irreversible insult to the central nervous system resulting in the “irreversible cessation of all functions of the entire brain, including the brainstem” (48). Current opinion holds brain death to be both biologically and philosophically valid, with some states providing accommodation periods for families or recognition of religious exemptions to death by neurologic criteria (49; 11).

Determination of death by neurologic criteria is an inconsistent protocol across the nation, and even hospital practices of addressing whether or not families object to neurologic determinations of death are heterogeneous (65; 39; 38). An AAN guideline on this issue will hopefully address the heterogeneity of hospital practices (30). Just as technologies were developed to allow for better organ donation, which came in tandem with the Uniform Determination of Death Act, it may become the case that new and sure to be controversial radical tissue preservation or reanimation techniques require a revision of existing brain death criteria and protocols (50).

Predictive testing. A goal of neurology and neuroscience research has been to increase early recognition of neurologic diseases and disorders through preclinical and predictive tests. In neurology, disease-modifying interventions are unique in that they require patients and providers to consider not only the condition the patient is experiencing but also who the patient may become as a result of disease progression or intervention. Recommendations for the assessment of capacity, surrogate decision-making, and seeking assent and dissent are pertinent in the context of both the progressive loss of cognitive function due to neurodegeneration and the incomplete autonomy of children and adolescents with neurologic disorders.

For conditions like autism spectrum disorder, early identification and intervention present unmatched opportunities for children to build critical skills before autistic characteristics fully emerge (55). Preclinical testing in other areas is aimed at advancing the understanding of neurologic and psychological conditions that currently have limited interventions, like Alzheimer disease and psychosis (05; 12). Although preclinical research certainly has laudable aims of improving identification and appropriate intervention for developing disease-modifying therapies, certain risks are inherent and should not be overlooked.

The communication of risks to patients may itself be problematic. Medical researchers may downplay or not recognize the nonbiological risks faced by a patient participating in predictive or prodromal testing. The endeavor to communicate potential harm is further complicated by the diversity of presentations and uncertainty surrounding the etiology and diagnosis of many neurologic disorders (68). Even when best efforts are made to explain risks, the participant may not fully understand the nature of the harms due to pervasive issues of scientific and numerical illiteracy. For example, it may be difficult for the research subject to understand how brain data may be uniquely identifiable and may, in the future, expose them to risks that are currently unforeseeable. Further, it is unclear how useful such assessments will be in the near and intermediate term as there currently are no “cures” for autism spectrum disorder, schizophrenia, or dementia. Essentially, the provider must strive to communicate risks as honestly as possible by tailoring the discussion to the method the subject best understands (69). “Risk” may not even be the most appropriate word choice, as neurodiversity advocates would argue that the “risk for developing” autism might better be described as a natural human variant not requiring “cures” or even “treatment.” As we are primarily in the early and research stages of these technologies, the development of appropriate semantics and strategies will need to be integrated into research.

Privacy is of great concern for individuals participating in preclinical research for neurologic disorders. Neurologic and psychiatric conditions being studied (such as schizophrenia or Alzheimer disease) are often stigmatized or may engender discrimination by future employers or insurers. Part of that discrimination from such a preclinical assessment likely arises from an expectation of diminished capacity for decision-making and autonomy. Currently, no legal antidiscrimination protections for nongenetic information exist, nor do privacy laws prevent authorized parties like potential employers from viewing research information that is part of the medical record (PPACA 42 U.S.C. § 300gg-4). Thus, research subjects could be vulnerable to financial and health penalties should their participation be disclosed or the confidentiality of their results breached. Compounding this issue is the uncertainty inherent in preclinically obtained results. Diagnostic error is not uncommon, and the high or unknown rates of false positives in experimental preclinical or prodromal tests may unfairly subject participants to discriminatory effects, regardless of test validity (47).

Diagnostic uncertainty in predictive testing may also jeopardize a child’s “right to an open future,” that is, the full range of the child’s future options and ability to meaningfully decide amongst them, may be precluded by parental decisions enacted before full development of the child’s autonomy (19; 43). For example, a parent electing predictive testing that indicates her child has autism spectrum disorder may enroll the child in a targeted academic program. This choice may be beneficial in providing appropriate skills if the diagnosis is correct, but in instances of false positives, it may limit the full range of choices and interactions that would have otherwise been available to the child.

Enhancement and cosmetic neurology. Neurotechnologies and neuropharmaceuticals are now being used not only for restorative or therapeutic purposes but also with the intent to optimize or enhance human neurologic functioning. Cognitive enhancement has long been sought by humans through physical, chemical, and technological means, but modern neurology is changing the degree to which these modifications may manifest (62).

Stimulation devices like deep brain stimulation and transcranial direct-current stimulation are both under study for their ability to augment certain cognitive abilities in healthy subjects. In particular, preliminary studies explored deep brain stimulation’s promise in memory enhancement, whereas transcranial direct-current stimulation data indicate improvements in attention, learning, and memory (15; 58). However, a study suggested no cognitive enhancement effects in healthy populations (03). Currently, deep brain stimulation remains relegated to physician-administered clinical trials due to the invasive nature of implantation, whereas transcranial direct-current stimulation has become a popular “DIY” method of cognitive enhancement and, thus, remains relatively unregulated (33). Although the goal of improved cognition is not outright unethical, there remains insufficient evidence about the effects of neurostimulation on brain health, identity, and self for endorsement of nontherapeutic application by medical professionals outside of the research setting.

Similarly, there has been increasing discourse surrounding the practice of pharmaceutical cognitive enhancement, in which nootropics and other stimulant drugs are employed to improve focus, motivation, attention, recall, and reaction time (07; 36). These practices predominantly arise in university student and professional populations (including physicians and scientists) with the aim of improving performance (24). Though nonprescription use of these drugs is illegal, the practice is not uncommon. Surveys suggest between 1% and 20% prevalence among healthy subjects (25). Although empirical evidence of the realized cognitive effects is currently limited, there are strong contraindications for the practice due to drug safety and side effects.

Further, ethical concerns about just access and individual autonomy must be addressed. The illicit nature of pharmacological cognitive enhancement means obtaining the drugs is expensive and may unfairly privilege those with preexisting economic advantages or increase disparities in cognitive capacity between those who demonstrate clinical need for a prescription and those simply wishing to gain an advantage. Some physicians already experience or have prescribed interventions for enhancement (31); the term “cosmetic neurology” has been used to describe a practice wherein neurologists may be asked to act more as “quality of life consultants” offering enhancements rather than treatments (13). Critiques of cognitive enhancement also extend beyond concerns of unknown harms, legality, fairness, and equity; some have argued that cognitive enhancement is an affront to the authenticity of one’s identity and a violation of nature’s gifts (35). Others fear that there will be implicit coercion to use cognitive enhancement to keep pace with a culture that keeps moving the goalpost of productivity.

Brain stimulation and identity. Brain interfacing technologies like deep brain stimulation are now being used experimentally for a host of neuropsychiatric disorders and as FDA-approved therapy for Parkinson disease, essential tremor, epilepsy, dystonia, and obsessive-compulsive disorder (28). In experimental and therapeutic contexts, deep brain stimulation and other brain-interfacing devices may pose unique threats to patients’ identity and privacy. Following patient reports about feeling distance from or a sense of strangeness with themselves after deep brain stimulation implantation and family reports of no longer “knowing” the patient when the device is turned on, many scholars expressed unease with the philosophical implications of a disease-modifying intervention that poses a significant threat to personal identity (27; 56; 41). These risks are poorly understood and may be difficult to communicate to patients during informed consent procedures. Although personality and mood alterations may enable deep brain stimulation to substantially contribute to neuroscientific and philosophical understanding about the nature and locus of identity and self-constituting attributes, debate persists about the acceptability of such unintended effects in the context of disease-modifying interventions. Deep brain stimulation and other novel brain-interfacing devices also may threaten patient or participant privacy, as neural data receive little protection under current policy (60).

Conclusion

Neuroethics discourse is a useful and necessary tool in clinical specialties like neurology, neurosurgery, and neuropsychology for exploring ethics of neurotechnology research and application, as well as social and policy issues associated with their use (53; 66; 51). As neuroscience advances and the opportunities for clinical interventions change, neurologists must be equipped to consider the implications of brain interventions on personhood and identity, autonomy and agency, as well as for informed consent. In the near future, neurologists will continue to encounter trenchant ethical problems in contexts of acquired injuries, brain stimulation and brain-computer interface technologies, predictive brain health assessments, disorders of consciousness, and end of life.