Keywords

Deep brain stimulation (DBS) is a fascinating procedure in terms of its history, its evolution in health care, and the questions it brings forth to medicine, ethics, and philosophy. From a historical perspective, DBS is a rather old technique, and its exploration began in the nineteen sixties (Talan 2009). At that time, DBS was trialed for Parkinson’s disease and pain treatment, but never gained in popularity given unconvincing results (Talan 2009; Miocinovic et al. 2013). In the nineteen eighties, interest was reignited when the French neurologist Alim-Louis Benabid and his team undertook investigations of neurostimulation for replicating the therapeutic effects of surgical lesions in the treatment of Parkinson’s disease, i.e., thalamotomy of the ventral intermediate thalamus. DBS gained new life with Benabid’s initial publication (Benabid et al. 1987) and subsequent publication of trial results (Benabid et al. 1993). Some of the core effects of DBS in Parkinson’s disease, such as rapid tremor reduction, were striking. This feature created lasting impressions that DBS has tremendous therapeutic power in new targets and conditions (Ford 2009). Unsurprisingly, this aspect of DBS was broadly captured in public discourse on DBS (Racine et al. 2007b). Promptly accompanying the evolution of clinical DBS, ethical discussion has led to the identification of important ethical challenges for the appropriate use of DBS in neurological and neuropsychiatric patients (e.g., in terms of patient screening procedures, informed consent ) (Fins 2000; Farris and Gianola 2009; Bell et al. 2009; Comité Consultatif National d’Ethique Pour les sciences de la vie et de la santé 2002).

Building on previous work of ours and others, we review in this chapter three key ethical principles at the core of contemporary biomedical ethicsFootnote 1 (Beauchamp and Childress 2009) and explain how conceptual and empirical research has helped to specify the meaning and scope of their application for DBS clinical practice. In doing so, we adopt a pragmatic perspective where ethical principles constitute hypotheses to test in light of their real-world implications and outcomes (Racine 2013). Further, ethical principles are part of an iterative (pragmatic) cycle of issue identification, deliberative creative moral thinking, and real-world testing (Racine 2013). In this respect, DBS for Parkinson’s disease presents a compelling case where ethical principles need to be considered and duly specified to capture how they can guide ethical research and clinical innovation. In return, through specification, we can enrich the meaning of ethical principles and increase their specificity. We hope that this contribution will inform readers and also stimulate discussion related to areas where important questions remain unanswered and where further research would need to be undertaken to understand and enact ethical principles.

1 Respect for Autonomy and Challenges Associated with the Profile of DBS

Respect for patient autonomy is a central component of contemporary medical ethics and bioethics (Beauchamp and Childress 2009). Much more than the simple application of the doctrine of “informed consent” and related concepts of assent and dissent, patient autonomy entails broader respect for the person able to make decisions on his or her own behalf (Beauchamp and Childress 2009). Patient autonomy has been fostered broadly and encompasses many aspects including informing the patient (e.g., health information, treatment options), engaging the patient in discussions and decisions about medical care, and supporting the patient in developing healthcare preferences and values. Hence, respect for autonomy offers a substantive paradigm of deep commitment to individual values and individual rights. However, in the context of DBS for Parkinson’s disease, challenges in the exercise and respect of patient autonomy can arise, for instance, because of the cognitive effects of Parkinson’s disease on decision-making, the effects of patient vulnerability and enthusiastic media depictions of DBS on patient expectations of treatment, and the challenges cliniciansFootnote 2 face in managing patient expectations.

1.1 Impacts of Cognitive Effects on Decision-Making

Since Parkinson’s disease can entail cognitive and psychiatric comorbidities, a number of ethical considerations for the informed consent process and autonomy surface. These considerations are not necessarily unique to Parkinson’s disease patients as they can extend to other neurodegenerative or neuropsychiatric disorders. Parkinson’s disease can impact cognition and mood, while in both Parkinson’s disease and some neurodegenerative or neuropsychiatric disorders, there can be deficits in executive function, attention, verbal fluency, and working memory (Kim 2004). However, it is important to note that a diagnosis of a neurodegenerative or neuropsychiatric disorder does not mean that patients necessarily relinquish their decision-making capacity. Empirical research has shown that, in some neurodegenerative conditions, a diagnosis should not rule out the capacity for patients to express healthcare preferences and participate in decision-making. Patients may prove to have a good understanding of the information regarding the procedure or understand related risks , benefits , and potential complications (Kim 2004). Notably, in patients with Parkinson’s disease suffering from cognitive deficits, empirical evidence has demonstrated impairments in the ability to efficiently encode and organize new medical information, but reasoning and personal appreciation of that information was not affected (Martin et al. 2008). Thus, in some instances, patients may be found to have impaired decisional capacity , but this does not necessarily negate their ability to be involved in the decision-making process. Clinicians ought to assess patients’ cognitive ability and bear potential challenges to decisional capacity in mind during the informed consent process, ensuring adequate understanding of potential risks, benefits, and outcomes of treatments.

1.2 Managing Patient Expectations

Risks associated with DBS which need to be disclosed includes those related to the actual surgical procedure as well as those related to the device and its operation. Additionally, discussion about the schedule of follow-up appointments for device programming should be stressed, as well as the time and commitment involved, to support an informed decision by patients. Discussion of benefits and outcomes can provide an additional challenge for clinicians, as patient expectations of DBS may be affected by patient vulnerability and/or media discourse on DBS (Racine et al. 2007b). Unrealistic expectations may also compromise patient autonomy and the informed consent process if patients do not fully appreciate the spectrum of possible risks and benefits.

1.3 The Effects of Patient Vulnerability

Since DBS is typically offered uniquely to patients at a late stage of Parkinson’s disease, they may have a heightened vulnerability that influences their willingness to consent. Although there have been calls for earlier DBS intervention (Woopen et al. 2013; Susman 2001), clinical guidelines, such as the 2012 Canadian Guidelines on Parkinson’s disease, consider surgical treatment to be an option only for advanced patients, when treatment of motor symptoms by other medical interventions fails (Grimes et al. 2012). Some bioethicists agree that, due to the severity of risks involved in DBS, the intervention should be offered only when no other treatment proves effective (Glannon 2010). However, since DBS is offered as a last option to control the symptoms of the disease, this can create a challenging context where patients may over-invest DBS with therapeutic outcomes it cannot deliver (e.g., tremors will disappear in all patients). This vulnerability could be easily exacerbated and could result in patients being overly willing to consent to DBS surgery due to desperation and hope for recovery. Studies examining the consent process in Parkinson’s disease for novel interventions have encountered a similar phenomenon of “hyped hope” in spite of unknown risks (Miller and Fins 2006), which, at least in the case of neural transplantation, can lead to highly problematic tendencies such as a willingness to “risk everything” for a treatment procedure (Lopes et al. 2003).

1.4 The Influence of Media on Patient Expectations

Media depictions of DBS can also contribute to unrealistic patient expectations. In previous research, we have shown that public discourse has portrayed DBS enthusiastically (Racine et al. 2007b). An increasing coverage of neurostimulation has suggested marked enthusiasm for the clinical translation of DBS. Many articles have described “miracle stories” where patients were literally cured (Racine et al. 2007b), while other print media headlines proclaimed broad clinical benefits beyond the treatment of Parkinson’s disease. Risk information and discussion of the ethical challenges of DBS was limited, resulting in the depiction of DBS as a promising therapy for neurodegenerative conditions.

The impact of enthusiastic media coverage is often hard to assess for methodological reasons. However, in a multi-site study of Canadian neurosurgical units with DBS programs, we found evidence that enthusiastic media reports were interacting with the prior vulnerability of patients (Bell et al. 2010). Clinicians interviewed in this study (e.g., neurosurgeons, neurologists, psychiatrists, and other clinical staff involved in DBS programs) reported a clear effect of enthusiastic media coverage on patient expectations. The unfortunate impact may then be a perceived failure of DBS to meet patient’s expectations, resulting in disappointment that can lead to negative consequences for the patient–provider relationship (see Fig. 1) (Bell et al. 2010). Patients should thus be prompted about the common pitfalls of media depictions of DBS (Racine et al. 2007a). However, the effects of enthusiastic public discourse on DBS are not entirely negative, as increased public awareness about DBS could inform patients and families about this treatment option and bring broader support to healthcare services for neurodegenerative conditions (though these positive features could be augmented) (Bell et al. 2009).

Fig. 1
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Desperation and media enthusiasm compound patient expectations—in the clinical context, hope and expectation in DBS for movement disorders challenge informed consent and can lead to a failure to meet pre-defined outcomes

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1.5 The Role of Clinicians in Managing Patient Expectations

Patient outcomes in DBS are complex: Some symptoms may improve, others not. DBS can also be transformative in its effects. We have demonstrated that patient expectations of outcomes can be unrealistic, which poses a challenge for clinicians who struggle to manage patient expectations (Bell et al. 2010) (see Table 1). In the literature, measures and practices to address unfounded hope and expectations have been put forth (see Table 2). At this time, more evidence should be gathered on these recommended measures, and dialogue with other clinical areas with similar features (e.g., clinical oncology research) could help tackle these challenges and lay out more comprehensive counseling approaches.

Table 1 High patient expectations of DBS candidates (section A) and clinicians’ reactions to expectations (section B) (adapted from Bell et al. 2009)
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While the context of DBS for Parkinson’s disease can raise many challenges in the exercise of patient autonomy, it is important to note that these challenges can also provide an opportunity to enrich the exercise of patient autonomy and to enhance the patient–clinician relationship. Challenges to autonomy should encourage clinicians to engage patients in discourse about their illness, the effects of different therapies, and an evaluation of how they are making their choices (including what their goals for treatment are, how they understand and value the different effects of interventions, and what considerations inform their choices). In the age of accessible online information, patients should also be directed to reputable sources of patient-oriented information (Racine et al. 2007a). Common patient-oriented documents available online include those by the National Institute of Neurological Disorders and Stroke’s patient page on DBS for Parkinson’s disease (National Institute of Neurological Disorders and Stroke 2012), the National Parkinson Foundation (National Parkinson Foundation 2012), as well as those published by academic centers such as the Cleveland Clinic (Cleveland Clinic 2013), and the University of Florida (University of Florida Center for Movement Disorders and Neurorestoration 2013)

Table 2 Core ethical principles and their specification as responsive practices within a pragmatic knowledge cycle—inspired by Bell et al. (2009, 2011b) (see text for other references)
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2 The Principle of Justice and How DBS, as an Expensive Intervention, Generates Questions for Equity and Fairness

In contemporary discussions, the principle of justice is often overshadowed by considerations related to benefit, risk, and the exercise of patient autonomy where individual rights and freedom anchor the dialogue. Concerned with the social exchange of goods within a population, the principle of justice may sometimes be trumped by other considerations, or altogether overlooked, when the primary deontological obligation of clinicians is focused on the individual patient’s care (World Medical Association 1948, revised May 2006). In addition, the principle of justice is complex, notably, because it can borrow different and sometimes radically opposing meanings such as (1) to each person an equal share; (2) to each person according to need; (3) to each person according to effort; (4) to each person according to contribution; (5) to each person according to merit; or (6) to each person according to free-market exchanges (Beauchamp and Childress 2009). In spite of this complexity or the primary obligation of physicians to act in the best interests of the individual patient, clinicians have arguably broader societal responsibilities related to resource allocation, use of health services, and access to health care. For example, the code of ethics of the Canadian Medical Association states that physicians should recognize the need to “promote equitable access to healthcare resources” and “use healthcare resources prudently” (Canadian Medical Association 2004).

2.1 DBS and Issues of Justice

In the context of DBS—a high cost (estimated in one US study at $69,329 in 2006 (Lad et al. 2010)) and increasingly routine procedure for Parkinson’s disease patients—issues of distributive justice including the equitable and fair allocation of resources must be considered. Despite the high costs of the surgery, device, and battery replacement, evidence supports the medical management of Parkinson’s disease patients with DBS to improve motor function and reduce motor fluctuations and medication side effects (Grimes et al. 2012). Moreover, cost-effectiveness of research recommends funding DBS for eligible patients, where not already funded or reimbursed, because of the overall reasonable incremental cost-utility (€6,700 per quality-adjusted life year) over best medical therapy (Dams et al. 2013) (see Dams et al. 2013 also for a review of the European literature on cost-effectiveness of DBS). Other European studies have shown that the total costs of caring for a patient with Parkinson’s disease decrease after surgery (Fraix et al. 2006; Meissner et al. 2005) and that the savings allow return on the procedure investment (approximately 37,000 € when the study was conducted) over 2.2 years (Fraix et al. 2006). Therefore, based on a position where cost-effectiveness forms a basis for assessing what interventions should be available, and where access is influenced by positive assessments of cost-effectiveness, the necessary evidence and impetus are present to make DBS available to eligible patients with Parkinson’s disease. Nonetheless, the principle of justice requires broader reflection than is provided by mere estimates of cost-effectiveness, and necessitates deliberation about to whom, how, and to what extent we can afford to, provide health services.

In fact, despite evidence demonstrating improvements in quality of life and motor symptoms and relative cost-effectiveness of DBS in Parkinson’s disease, DBS represents an immediate and large investment. As such, regulators, administrators, and insurers may feel obliged to restrict the amount of DBS procedures performed, impacting access to and distribution of resources for DBS. Unfortunately, although practice guidelines support the use of DBS in Parkinson’s disease for good candidates, they do little to address issues of potential inequity in access or resource allocation that might be present. Issues of access and resource limitations are sometimes unacknowledged realities of healthcare delivery, but have important ramifications for clinicians, patients, and their families. In a study of Canadian DBS programs, we found widely discrepant approaches to resource allocation, leading to diverging scenarios for access to DBS (See Table 3), and evidence suggesting wide-ranging challenges for access to DBS (Bell et al. 2011a). We discovered that even patient selection can be impacted by the specific resource situation of a hospital. In some cases, clinicians reported that resource limitations affect how quickly patients can be screened (for instance, how quickly neuropsychological assessments can be made) or affect how many patients can even be provided with DBS in any given budgetary year. At the same time, clinicians working at health centers in other regions did not report facing challenges due to resource limitations or in meeting demand for DBS. Another center reported that despite overall limitations set on the resources that can be expended (i.e., personnel), they felt the waiting time is appropriate (see Table 3).

Table 3 Wide-ranging scenarios of access and resource allocation in Canadian DBS programs (adapted from Bell et al. 2011a)a
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2.2 Access to DBS in the Canadian Context

Given that provincial healthcare systems are bound to federal obligations of access and performance through the Canadian Healthcare Act , to “protect, promote and restore the physical and mental well-being” of Canadians by ensuring “free and universal access to publicly insured health care” (Government of Canada 1984), it is striking to find that these variations can exist. We also question whether patients, families, or clinicians are truly aware of potential differences in access across the country for approved health interventions. Ultimately, the federal legislation only requires the provinces to guarantee the comprehensive coverage of insured care, to cover insurance for all residents, and to ensure equal access to insured services (Government of Canada 1984). It does not explicitly guide the provinces, who independently administer healthcare services, on how to provide access to insured services nor does it clearly mandate the level or standard of health care between provinces. Importantly, access is meant to be equitable, but the meaning of equity remains unclear. In the case of DBS, how can this resource be allocated equitably? Suggestions on how each province could be allocated DBS implantations include equally (i.e. the same share to each province), allocation based on the number of cases of Parkinson’s disease, or allocation based on the resources already available (e.g., specialized neurosurgeons). Ultimately, the current mechanism by which healthcare resources are administered in Canada may lead to a neglect of the broader national needs, allowing disparities or variation in access to persist.

Multiple factors could explain such an internally discrepant situation. Challenges in access within publically funded systems have been noted, particularly in the field of medical devices. For example, in Canada , variation in access to implantable cardioverter defibrillators (ICDs) has been shown, as some provinces (i.e., British Columbia, Saskatchewan, Manitoba, Prince Edward Island) fall well below the national average of implantation of ICDs in Canada (Canadian Heart Rhythm Task Force MEDEC 2004). In this case, different factors could explain these variations such as a culture of under-referral (e.g., physicians are hesitant to refer patients to programs that they sense are unavailable, or when they think that wait lists are too long), lack of national standards for access to ICDs, lack of a tertiary center in a province, and some clinical programs being held to fixed budgets (Simpson et al. 2005). Variations in implantation rates of ICDs have also been observed between and within some European countries (Ector et al. 2001; Boriani et al. 2010; Cunningham et al. 2005; Mond and Proclemer 2011). Widely different reasons for these variations have been proposed (McComb et al. 2009). In one Canadian province (Ontario), important inequalities in ICD implantations between those living in urban areas and rural regions have been shown (Lee et al. 2008). Similar inequalities may exist in the context of DBS implantation; however, intra-provincial regional variation in this context has been largely unexplored, likely because of the limited centers across the country providing this specialized neurosurgery (approximately one or two academic centers in every province). In light of this, it is likely that patients have to travel from remote communities to larger centers or, if no program is available, travel from one province to another to access DBS. For DBS, further investigation of how rural populations are serviced by larger academic and urban centers is warranted. Other issues impacting access to DBS could relate to manpower and specialty training in relevant fields (e.g., functional neurosurgery); complex tensions exist in Canada between recognized shortages in specialized practitioners in certain fields and a lack of jobs for many postgraduates in the same medical specialties (Woodrow et al. 2006; Vogel 2011). Moreover, a 2005 report by the Institute for Clinical Evaluative Sciences, which examined the Health Human Resources for Neurosurgical Services in Ontario, describes that one of the visible symptoms of stress in the neurosurgical service delivery system is unequal access to appropriate technology and care across the province (Tepper et al. 2005).

The challenges faced by some clinicians with regard to access and resource restrictions for DBS mean there are difficult rationing and resource allocation decisions to be made. These situations become even more challenging when clinicians are not informed about the allocation process, but are nevertheless charged with explaining to patients and their caregivers allocation decisions, the reasons for wait lists, and the variations between regions or provinces (Holloway et al. 2000). In the context of DBS, resource allocation issues can translate into a number of difficult and arguably unethical situations that require transparency when dealing with patients and families. For example, a Parkinson’s disease patient who was a good candidate can develop comorbid conditions (e.g., depression or dementia), while long wait lists may lead to necessitate re-assessments (Bell et al. 2009, 2011a). This leads to a deleterious cycle, where a long wait list necessitates frequent re-assessments, and frequent re-assessments add to the long wait list. As a result, resources must be re-allocated for the same patient and there are even more substantial personal implications for patients and families who are on waiting lists. Table 2 presents some responsive practices to respond to challenges of justice.

3 Non-maleficence and Psychosocial Aspects of DBS

The principle of “first, do no harm” captured in the Latin aphorism “primum non nocere” has been an enduring maxim of medical ethics. Although often attributed to Hippocrates who called upon physicians to abstain from doing harm, its origins are debated (Beauchamp and Childress 2009).

Modern descriptions of the principle have focused on avoidance of physical harms to patients (Beauchamp and Childress 2009). However, non-maleficence cannot be interpreted as the absolute avoidance of harm since some side effects are almost always to be expected from treatments. Hence, the principle stresses rather the avoidance of undue or unjustified harm. Accordingly, harms need to be considered in relationship to expected benefits. Further, harm can be modulated by the clinical context and social or personal circumstances in which an intervention is offered. Therefore, a contextual appreciation of what the principle means for a specific patient in a specific context needs to take place.

The historical descriptions found in the Latin formulation and related statements in Hippocratic writings also capture another aspect, that is, the fundamental or primary nature of the principle that “first” or “above all,” clinicians should not engender harm. Therefore, the principle mandates a prudential attitude calling for a circumspect and reflexive evaluation of one’s own knowledge about the beneficial effects of a treatment and that, first and foremost, the physician should avoid harming the patient. This prudential attitude is certainly relevant in the context of DBS given its rapid evolution, partial knowledge of its long-term, potential global effects on the patient, and high expectations toward DBS upheld by patients and their families.

Beyond the physical harms (and benefits) associated with DBS (discussed above), another set of harmful (or potentially beneficial) consequences (Ashkan et al. 2013; Wolz et al. 2012; Sevillano-Garcia and Manso-Calderon 2010) concern the psychosocial (or “non-motor”) effects of DBS in Parkinson’s disease. These consequences of DBS on quality of life and more comprehensive psychosocial domains are still poorly understood (Sandvik et al. 2012). A landmark qualitative study, published in two papers, showed clearly the issue at hand; contrary to studies suggesting increased independent living after surgery (Krack et al. 2003), patients faced difficulties with their familial or marital relationships after surgery and felt conflicted about returning to work (Agid et al. 2006; Schüpbach et al. 2006). In this study, Schüpbach and colleagues (2006) examined 29 patients with Parkinson’s disease before and 18 to 24 months after stimulation. Follow-ups and in-depth interviews with patients, their spouses, and families revealed three challenging areas: the patients’ perception of themselves and their bodies (the self), the couple (the proximate other), and the social and professional life (the distal other) (Schüpbach et al. 2006). Some patients expressed difficultly accepting lost years of their lives after being relieved by DBS surgery, while others did not adapt to the sudden motor improvement and still associated with their “ill selves” (Agid et al. 2006). Additionally, a qualitative interview study of patients and clinicians performed by Gisquet demonstrated that some patients who have undergone DBS communicate “a loss of control over managing their illness and over their life,” and patients felt tied to the medical team to manage their stimulator and their treatment unlike before (Gisquet 2008). Other authors have proposed that DBS may create adaptation challenges for patients because of a discord between the patients’ narrative identity before and after DBS (Schechtman 2010), or because of an abrupt alteration created in the patients’ experience of chronic illness (Gisquet 2008). The rapid clinical changes caused by DBS could be partly responsible for such consequences. In the context of epilepsy, others have found that “sudden health” subsequent to medical or surgical treatment “may eliminate the patient’s disease and the disease label from the patient’s identity” (Seaburn and Erba 2003). In our own research across Canadian surgical centers, we have found corroboration for the findings of Agid, Schüpbach, and colleagues (Bell et al. 2011a, b). Table 4 features examples of testimonials illustrating these three domains and their profound impact on the patient and his social networks (Bell et al. 2011b). Readers should note that the prevalence of such experiences needs to be better established.

Table 4 Illustrative examples of DBS implications for self, proximate other, and distal other (from Bell et al. 2011b)
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3.1 Impact on the Self

The influence of DBS on behavior and personality has not clearly been delineated, and there is conflicting evidence that changes in mood and anxiety occur after DBS (Ballanger et al. 2009; Bell et al. 2009; Frank et al. 2007; Halbig et al. 2009). Moreover, Gisquet has suggested that the experience of mood or behavior changes after DBS may be so far-reaching for patients that they “have the feeling that their identity has been affected” (Gisquet 2008). The larger question remains whether these types of changes, or others observed after DBS, are profound alterations in the personality of the patient (Synofzik and Schlaepfer 2008). Importantly, changes in mood or behavior observed after DBS could be unrelated to the procedure itself, but rather due to the stimulation parameters and targets of stimulation as well as the psychological profile of patients (e.g., cognitive decline prior to surgery), age, and prior L-dopa response (Smeding et al. 2011; Soulas et al. 2011). Discussion regarding the site of choice for stimulation in advanced Parkinson’s disease patients and the side effects or advantages of these targets continues (Follett and Torres-Russotto 2012). For example, stimulation of the subthalamic nucleus (STN) may result in more mood-related adverse events (e.g., depression, anxiety) than stimulation of the pallidal target (Vitek 2002). These adverse events to mood may be higher over the long term in patients who undergo STN stimulation than globus pallidus interna (GPi) stimulation (Moro et al. 2010). Okun and colleagues (2009) have observed that stimulating the ventral contacts of both STN and GPi DBS produces negative mood effects, which they suggest is due to the ventral spread of activity to non-motor and limbic circuits (Okun et al. 2009). Improved understanding of stimulation target sites will enable better management of adverse mood events.

Unfortunately, there is only a small but still thought-provoking literature regarding adaptation challenges for Parkinson’s disease patients after DBS (Agid et al. 2006; Schupbach and Agid 2008; Schüpbach et al. 2006). In spite of the lack of causal explanations for such changes, in their obligation to not engender harm, clinicians have to bear in mind such consequences. Psychological care and psychosocial education could be relevant components to include in the care of patients to mitigate harms (Cohen et al. 2007). Research should document psychosocial well-being after surgery as well as conditions and interventions for better outcomes and quality of life. Importantly, some recent clinical trials are taking into account the patient’s specific goals in choosing target stimulation sites, because this choice may have an impact on the symptoms they correct (Bell and Racine 2013).

3.2 Proximate Other

Data gathered by our group and others show the existence of psychosocial challenges between the patient and the spouse (and proximate others) after DBS (Agid et al. 2006; Bell et al. 2011b; Schüpbach et al. 2006). One scenario involves patients reclaiming the independence they previously lost and, as a result, rejecting, advertently or inadvertently, their spouse as caregiver, causing the spouse to give up the role they had been playing over the length of the illness. Another scenario involves the patient being “rejected by (the) spouse” leading to, for example, marital problems because the spouse’s expectations of outcome are not met by the patient’s actual real-life abilities (Agid et al. 2006; Schüpbach et al. 2006). Agid et al. report that 65 % of married patients experienced a “conjugal crisis” following DBS (Agid et al. 2006). Moreover, of the couples studied, Schüpbach et al. (2006) reported that 33 % of the spouses suffered depression after their partners underwent DBS. They also report that a greater percentage of patients were “rejected by their spouse,” but our own research suggests this could be a minority (Bell et al. 2011b). Similar inter-spouse conflicts have been described by others where caregivers were reluctant to maintain the role of caregiver after surgery, while patients were reluctant to give up the attention and special treatments that they received from others prior to DBS (Perozzo et al. 2001). The failure of DBS to meet spousal or caregiver expectations, much like the failure of reaching patient expectations, risks creating disappointment and conflict (Bell et al. 2010), a phenomenon also observed in other neurosurgical procedures (Bladin 1992).

Based on our work and that of others, it is clear that the factors contributing to marital conflict following DBS and possible ways to manage or alleviate patient and caregiver distress warrant further investigation. Specifically, a better understanding of how spousal and patient expectations of outcomes can influence the marital relationship after DBS may constitute a key area where DBS healthcare teams could intervene to minimize harms and enhance quality of life.

3.3 Distal Other

The topics of employment and occupational disability have not been extensively discussed or investigated in the context of DBS. General literature on Parkinson’s disease patients suggests that many Parkinson’s disease patients can rapidly loose employment after being diagnosed, or retire early (Schrag et al. 2003), and most Parkinson’s disease patients are no longer working within 10 years of diagnosis (Schrag and Banks 2006). Nonetheless, loss of employment might be highly consequential for young (onset before age 50) Parkinson’s disease patients, potentially leading to marital conflicts and a greater perceived impact of the disease (Schrag et al. 2003).

Following DBS, Agid et al. have described that a “retrospective disaster” can be experienced by patients. Although their motor symptoms have improved, patients have suffered irreparable consequences of the disorder such as the loss of employment (Agid et al. 2006). For some patients, the loss of opportunities to gain the skills necessary to be employable may pose the specific problem, rather than the loss of current employment. Highlighting this challenge is the regret that some patients may feel, following improvement of symptoms with DBS, due to not having achieved what they considered to be their full potential. In order to minimize harm to Parkinson’s disease patients with respect to “distal others,” occupation, and social roles, there could be a need for Parkinson’s disease patients to plan for the future earlier in their disease progression and for dedicated support to help them remain in the workforce later into the course of their disease (Schrag and Banks 2006). There may also be a role for clinicians to assist patients and employers in finding appropriate new roles in the workplace for patients with DBS. Unfortunately, there are no data, to our knowledge, which captures the challenges directly related to social support programs and access for patients to such services after DBS. Alternatively, earlier DBS could be a promising way to prevent loss of employment and its related financial implications (Woopen et al. 2013). This does not imply that younger patients are all good candidates for DBS nor that DBS will have a (positive or negative) impact on employment or occupational opportunities for every patient, since many patients undergoing DBS for Parkinson’s disease may have already left their professional occupation.

The principle of non-maleficence brings forth questions about the known physical and psychosocial harms of DBS. At this time, there are very little data demonstrating or replicating some of the important results on the effects of DBS on proximate and distal others, or to oneself. More empirical work to understand this problem, hopefully feeding into consent processes and practices for patient autonomy, could help better inform patients about these effects. They could also be used to structure programs (e.g., long-term follow-up, psychological support), or simply increase awareness about these effects for patients, families, and clinicians (Mathieu et al. 2011). Table 2 captures some recommendations to promote non-maleficence in DBS programs.

4 General Conclusion

Following the analysis of some of the emerging issues within three key principles of contemporary biomedical ethics, this paper has reviewed some of the basic ethical challenges that DBS raises in the context of Parkinson’s disease. We hope to have shown the relevance of ethical analysis to clinical practice, and the potential for ethical research and deliberation to generate concrete ideas for practice changes and clinical innovation. At this time, more precise understandings of the issues would be beneficial. Participatory and action research could lead to the greatest insights into the impact and benefits of tackling ethical challenges explicitly and directly in the context of DBS for Parkinson’s disease.