Clinical Ethics in the Context of Deep Brain Stimulation for Movement Disorders

New Perspectives of Deep Brain Stimulation Indications for Parkinson's Disease: A Critical Review

Deep Brain Stimulation (DBS) is an effective treatment option for patients with dopaminergic complications of Parkinson's disease (PD) and drug-refractory PD tremor. However, DBS and its indications can be challenging, and they are not often debated in the medical community. Through a critical narrative review, the objective of this paper is to improve the comprehension of DBS indications and help to solve the puzzle that this process can be. Proper patient selection is the first step for a good surgical outcome. In this review, then, relevant considerations are discussed, involving PD genes, PD phenotypes, indications of early stages, non-motor symptoms, neuroimaging predictors, comorbidities, and age. Individualized approaches are encouraged, including clinical and radiological factors. Social support during the whole follow-up and expectations alignment are necessary through this process and are also debated.

Brain Pioneers and Moral Entanglement: An Argument for Post-trial Responsibilities in Neural-Device Trials

We argue that in implanted neurotechnology research, participants and researchers experience what Henry Richardson has called "moral entanglement." Participants partially entrust researchers with access to their brains and thus to information that would otherwise be private, leading to created intimacies and special obligations of beneficence for researchers and research funding agencies. One of these obligations, we argue, is about continued access to beneficial technology once a trial ends. We make the case for moral entanglement in this context through exploration of participants' vulnerability, uncompensated risks and burdens, depth of relationship with the research team, and dependence on researchers in implanted neurotechnology trials.

Translational Neuroethics: A Vision for a More Integrated, Inclusive, and Impactful Field

As early-career neuroethicists, we come to the field of neuroethics at a unique moment: we are well-situated to consider nearly two decades of neuroethics scholarship and identify challenges that have persisted across time. But we are also looking squarely ahead, embarking on the next generation of exciting and productive neuroethics scholarship. In this article, we both reflect backwards and turn our gaze forward. First, we highlight criticisms of neuroethics, both from scholars within the field and outside it, that have focused on speculation and lack of skepticism; the dearth of consideration of broader social issues such as justice and equality, both with regard to who speaks for neuroethics as a field and who benefits from its recommendations and findings; and the insufficient focus on the practical impact of our ethical work. Second, we embrace the concept of "translational neuroethics" to outline a vision for neuroethics that is integrated, inclusive, and impactful. Integration can help us identify more pertinent, real-world issues, and move away from speculation; inclusivity can help ensure that the questions we attend to are not merely relevant to a single subgroup but aim toward just distribution of benefits; and impact can help us think beyond guidelines and recommendations to focus on implementation. Our goal is for this call to action to help shape neuroethics into a discipline that develops rigorous research agendas through relationships with interdisciplinary partners, that is broadly inclusive and attends to issues beyond novel neurotechnologies, and that is devoted to the translation of scholarship into practice.

The Role of Family Members in Psychiatric Deep Brain Stimulation Trials: More Than Psychosocial Support

Family members can provide crucial support to individuals participating in clinical trials. In research on the "newest frontier" of Deep Brain Stimulation (DBS)-the use of DBS for psychiatric conditions-family member support is frequently listed as a criterion for trial enrollment. Despite the significance of family members, qualitative ethics research on DBS for psychiatric conditions has focused almost exclusively on the perspectives and experiences of DBS recipients. This qualitative study is one of the first to include both DBS recipients and their family members as interview participants. Using dyadic thematic analysis-an approach that takes both the individuals and the relationship as units of analyses-this study analyzes the complex ways in which family relationships can affect DBS trial participation, and how DBS trial participation in turn influences family relationships. Based on these findings, we propose ways to improve study designs to better take family relationships into account, and better support family members in taking on the complex, essential roles that they play in DBS trials for psychiatric conditions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12152-023-09520-7.

A ética na investigação científica

A ética em investigação é uma matéria estudada há várias décadas, dado o interesse no meio académico e científico. Ao realizar-se uma revisão narrativa com o objetivo de conhecer os pressupostos éticos na investigação em doença de Parkinson, refletiu-se também a possibilidade de se interiorizar a perspetiva de Freire no ato de investigar. Uma nova corrente de investigação assente na pedagogia crítica de Freire é simultaneamente refletir acerca dos domínios ontológico, ideológico, político e de identidade cultural descritos ao longo da sua obra, e baseados na consciência ético-crítica. Constituem-se como requisitos éticos da investigação clínica em doença de Parkinson: (1) – respeito pelos participantes; (2) – avaliação do risco/benefício; (3) – consentimento informado; (4) –adicionar valor; (5) – validade científica; (6) – seleção criteriosa dos participantes; (7) – acesso independente ao estudo. As evidências científicas são consensuais, verificando-se a inclusão destas pessoas num grupo de participantes mais amplo, atendendo à sua condição de vulnerabilidade.

Patients with Cognitive Impairment in Parkinson's Disease Benefit from Deep Brain Stimulation: A Case-Control Study

Background

Deep brain stimulation (DBS) for Parkinson's disease (PD) is generally contraindicated in persons with dementia but it is frequently performed in people with mild cognitive impairment or normal cognition, and current clinical guidelines are primarily based on these cohorts.

Objectives

To determine if moderately cognitive impaired individuals including those with mild dementia could meaningfully benefit from DBS in terms of motor and non-motor outcomes.

Methods

In this retrospective case-control study, we identified a cohort of 40 patients with PD who exhibited moderate (two or more standard deviations below normative scores) cognitive impairment (CI) during presurgical workup and compared their 1-year clinical outcomes to a cohort of 40 matched patients with normal cognition (NC). The surgery targeted subthalamus, pallidus or motor thalamus, in a unilateral, bilateral or staged approach.

Results

At preoperative baseline, the CI cohort had higher Unified Parkinson's Disease Rating Scale (UPDRS) subscores, but similar levodopa responsiveness compared to the NC cohort. The NC and CI cohorts demonstrated comparable degrees of postoperative improvement in the OFF-medication motor scores, motor fluctuations, and medication reduction. There was no difference in adverse event rates between the two cohorts. Outcomes in the CI cohort did not depend on the target, surgical staging, or impaired cognitive domain.

Conclusions

Moderately cognitively impaired patients with PD can experience meaningful motor benefit and medication reduction with DBS.

Toward personalized medicine in connectomic deep brain stimulation

At the group-level, deep brain stimulation leads to significant therapeutic benefit in a multitude of neurological and neuropsychiatric disorders. At the single-patient level, however, symptoms may sometimes persist despite "optimal" electrode placement at established treatment coordinates. This may be partly explained by limitations of disease-centric strategies that are unable to account for heterogeneous phenotypes and comorbidities observed in clinical practice. Instead, tailoring electrode placement and programming to individual patients' symptom profiles may increase the fraction of top-responding patients. Here, we propose a three-step, circuit-based framework with the aim of developing patient-specific treatment targets that address the unique symptom constellation prevalent in each patient. First, we describe how a symptom network target library could be established by mapping beneficial or undesirable DBS effects to distinct circuits based on (retrospective) group-level data. Second, we suggest ways of matching the resulting symptom networks to circuits defined in the individual patient (template matching). Third, we introduce network blending as a strategy to calculate optimal stimulation targets and parameters by selecting and weighting a set of symptom-specific networks based on the symptom profile and subjective priorities of the individual patient. We integrate the approach with published literature and conclude by discussing limitations and future challenges.

Trading Vulnerabilities: Living with Parkinson's Disease before and after Deep Brain Stimulation

Implanted medical devices-for example, cardiac defibrillators, deep brain stimulators, and insulin pumps-offer users the possibility of regaining some control over an increasingly unruly body, the opportunity to become part "cyborg" in service of addressing pressing health needs. We recognize the value and effectiveness of such devices, but call attention to what may be less clear to potential users-that their vulnerabilities may not entirely disappear but instead shift. We explore the kinds of shifting vulnerabilities experienced by people with Parkinson's disease (PD) who receive therapeutic deep brain stimulators to help control their tremors and other symptoms of PD.

Bringing Advanced Therapies for Parkinson's Disease to the Clinic: An Analysis of Ethical Issues

Advanced therapies for Parkinson’s disease (PD) constitute a broad range of treatments, each presenting specific ethical challenges. Some of these therapies are established and in clinical use, like device-aided therapies, and others, based on advanced therapeutic medicinal products (ATMPs), are still in early stage of clinical trials. This paper focuses on some common ethical issues arising in these two categories of advanced therapies, especially challenges arising when advanced therapies are proposed to PD patients in the form of advanced care, under a clinical trial, or, in case of ATMPs, under the “hospital exemption” rule. The ethical issues covered here relate mainly to ensuring informed consent in these different contexts, to the stakeholder role of patient’s non-professional caretakers, such as family, and to patient safety in treatments under “hospital exemption”. To illustrate the points discussed in connection with “hospital exemption” rule, the example of the EU has been chosen. This paper does not claim completeness of ethical issues raised by bringing advanced therapies for PD to the clinic, but rather presents examples of ethical challenges in this context.

Patients' shifting goals for deep brain stimulation and informed consent

OBJECTIVE

To determine using a repeated-measures, prospective design whether deep brain stimulation (DBS) results in changes in the importance of symptom and behavioral goals individually identified by patients with Parkinson disease (PD) before DBS surgery.

METHODS

Fifty-two participants recruited from a consecutive series completed a semistructured interview soliciting their rank-ordered symptom and behavioral goals and corresponding visual analog scales measuring perceived symptom severity and limits to goal attainment. Rank orders were reassessed at 2 times after DBS. Changes in rank order over time were examined with χ² analyses. The relationships between change in symptom severity/limits to behavioral goal attainment and change in rank order were examined with mixed-effects linear regression models.

RESULTS

Most participants changed the rank order of their symptom (81%) and behavioral (77%) goals 3 months after DBS surgery. Change in rank order of symptom goals was significantly related to change in severity ratings such that improvements in self-reported symptom severity were associated with reductions in rank. In contrast, no such relationship was evident for the behavioral goals.

CONCLUSION

These data illustrate how patients' primary goals for DBS shift early in stimulation and highlight the important differences between symptom and behavioral goals. Changes in the rank order of symptom goals were related to changes in symptom severity, whereas subtler shifts in behavioral goals were unrelated to improvements after DBS. This observation suggests that DBS does not affect goals that may be more reflective of core personal values. The findings provide empiric data that can help improve the informed consent process.