Shaking Up the Debate: Ensuring the Ethical Use of DBS Intervention Criteria for Mid-Stage Parkinson's Patients

Deep Brain Stimulation for Parkinson’s Disease: Why Earlier Use Makes Shared Decision Making Important

Introduction

As deep brain stimulation (DBS) has shifted to being used earlier during Parkinson’s disease (PD), data is lacking regarding patient specific attitudes, preferences, and factors which may influence the timing of and decision to proceed with DBS in the United States. This study aims to identify and compare attitudes and preferences regarding the earlier use of DBS in Parkinson’s patients who have and have not undergone DBS.

Methods

We developed an online survey concerning attitudes about DBS and its timing in PD. The survey was distributed nationally in the United States via the Michael J. Fox Foundation Trial Finder, the American Parkinson Disease Association flyers, and as a link on the Parkinson Alliance website. Differences in responses between PD DBS and non-DBS patients were assessed.

Results

A total of 445 patients with PD met eligibility criteria for the survey of which 160 self-identified as having undergone DBS. Fifty-five percent (n = 124) of non-DBS patients believed that DBS for PD should only be considered after all medication options have been tried. Patients favoring early DBS had fewer concerns regarding the surgery than those favoring later DBS.

Conclusion

Our findings highlight a variety of important considerations and concerns patients have regarding DBS and its timing. These viewpoints are important aspects of shared decision-making, as they help to identify patients’ preferences, values, and goals, which should enable providers to better navigate, with their patients, the decision path for therapeutic options to consider.

Deep Brain Stimulation for Parkinson's Disease: Currents Status and Emerging Concepts

The clinical application of DBS has become manifold and there has been a tremendous growth in DBS technology in the last few decades making it safer and user friendly. The earlier concept of its delayed application in motor fluctuations of Parkinson's disease has been replaced by Class-I evidence of EARLY-STIM trial in 2013, leading to its FDA approval to be used in early-stage despite criticism. Various studies have provided evidence of beneficial effects of bilateral STN-DBS on both motor as well as nonmotor symptoms and different new targets such as the pedunculopontine nucleus, posterior subthalamic area or caudal zona incerta, centromedian-parafascicular complex, and substantia nigra pars reticulata have now become a new area of interest in addition to the subthalamic nucleus and globus pallidus internus for the alleviation of both motor and nonmotor symptoms of Parkinson's disease. New data has confirmed that the DBS is clinically as effective and safe in elderly patients as it is in younger ones. Technological advances like current steering, directional leads, and closed-loop DBS are directed towards reducing the stimulation-induced adverse effects and preservation of the battery life for a longer period. Results of the long-term efficacy of DBS on Parkinson's disease are now available. These have shown that as the motor benefit continues, the clinical progression of Parkinson's disease also continues. We plan to discuss all these in this paper.

Perspectives on Deep Brain Stimulation and Its Earlier Use for Parkinson's Disease: A Qualitative Study of US Patients

Background: Deep brain stimulation (DBS) is being used earlier than was previously the case in the disease progression in people with Parkinson’s disease (PD). To explore preferences about the timing of DBS, we asked PD patients with DBS whether they would have preferred the implantation procedure to have occurred earlier after diagnosis. Methods: Twenty Michigan-based patients were interviewed about both their experiences with DBS as well as their attitudes regarding the possible earlier use of DBS. We used a structured interview, with both closed and open-ended questions. Interviews were transcribed verbatim and analyzed using a mixed-methods approach. Results: We found that the majority of our participants (72%) had high overall satisfaction with DBS in addressing motor symptoms (mean of 7.5/10) and quality of life (mean of 8.25/10). Participants were mixed about whether they would have undergone DBS earlier than they did, with five participants being unsure and the remaining nearly equally divided between yes and no. Conclusion: Patient attitudes on the early use of DBS were mixed. Our results suggest that while patients were grateful for improvements experienced with DBS, they would not necessarily have endorsed its implementation earlier in their disease progression. Larger studies are needed to further examine our findings.

Perspectives on the Earlier Use of Deep Brain Stimulation for Parkinson Disease from a Qualitative Study of U.S. Clinicians

BACKGROUND

In November 2015, the U.S. Food and Drug Administration (FDA) approved the use of deep brain stimulation (DBS) therapy in people with Parkinson's disease (PD) "of at least four years duration and with a recent onset of motor complications, or motor complications of longer-standing duration that are not adequately controlled with medication." Although the full implications of this more recent approval are yet to be determined, to date, there are no strict criteria defining appropriate earlier use of DBS. As such, confusion remains regarding the actual meaning of early DBS initiation. To better inform responsive policy, we sought the perspectives of movement disorder neurologists and neurosurgeons regarding the earlier use of DBS. Insights from these clinicians are key to developing appropriate clinical guidelines and determining how early is too early. The objective of this study is to explore attitudes among clinicians toward the earlier use of DBS for PD.

METHODS

Twelve Michigan-based clinicians were interviewed both about DBS referral/use processes and their perspectives regarding the earlier use of DBS in PD. We used a structured interview with closed- and open-ended questions. All interviews were transcribed verbatim and analyzed using a mixed-method approach.

RESULTS

We found that most clinicians considered earlier use not solely to be time dependent but instead determined by patient symptoms. Only 16.8% were aware of the FDA's recent indication of early use of DBS, with 25% of our respondents being unsure as to whether it should be seen as an early treatment modality. On average, neurologists suggested DBS as the next treatment option, after medications have been exhausted, typically 6 years after diagnosis.

CONCLUSIONS

There remain wide variations in terms of clinicians' parameters for referrals and timing of DBS. Larger studies are needed to support or refute our findings.

Post mortem examination of Parkinson's disease brains suggests decline in mitochondrial biomass, reversed by deep brain stimulation of subthalamic nucleus

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is the most commonly used surgical treatment for Parkinson's disease (PD). The disease-modifying aspects of DBS at a cellular level are not fully understood, and the key question of the effect of DBS on the degeneration of the dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) remains to be answered. A major technical hurdle in determining any neuroprotective effect by DBS is its use in mid- to late-stage patients with PD when a majority of the DA neurons have been lost. In this work, we hypothesized that the long-term clinical benefits of DBS are, at least in part, due to a neuromodulatory effect on the SNpc neurons. These changes would affect cellular energetics and mitochondrial metabolism. We examined the number and volume of mitochondria as well as their vicinity to the DA presynaptic terminals postmortem caudate and putamen of 3 healthy individuals, 4 PD cases, and 3 DBS-treated patients. PD seems to have caused an increase in the mean distance between mitochondria and presynaptic terminals as well as a decrease in mean mitochondrial volume and numbers in DA projections. Although there was no difference in distance between mitochondria and presynaptic terminals of SNpc neurons in PD brains vs. DBS-treated brains, DBS treatment seemed to have inhibited or reversed the reduction in mitochondrial volume and numbers caused by PD. These results suggest enhanced metabolic plasticity leading to neuroprotection in the SNpc as a result of STN-DBS.-Mallach, A., Weinert, M., Arthur, J., Gveric, D., Tierney, T. S., Alavian, K. N. Post mortem examination of Parkinson's disease brains suggests decline in mitochondrial biomass, reversed by deep brain stimulation of subthalamic nucleus.

Neuroethics of Neuromodulation: An Update

This article reviews neuroethics issues that arise with the development, translation, and use of technologies for neuromodulation. Three electronic databases (PubMed, Embase, and PhilPapers) were searched for relevant articles published between 1/1/16 - 6/26/18. We focus on pressing ethical issues related to the use of deep brain stimulation (DBS), adaptive DBS (aDBS), transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and associated technologies. The neuroethics issues we address include privacy, continued access to devices, device removal, do-it-yourself neurostimulation, neuroenhancement, media coverage, changes in personal identity and agency, informed consent, and neuromodulation in minors. This review should be of assistance to a variety of stakeholders, including neurotechnology developers, as they make important decisions that will drive these neurotechnologies.

Combination of CDNF and Deep Brain Stimulation Decreases Neurological Deficits in Late-stage Model Parkinson's Disease

Several neurotrophic factors (NTF) are shown to be neuroprotective and neurorestorative in pre-clinical animal models for Parkinson's disease (PD), particularly in models where striatal dopamine neuron innervation partially exists. The results of clinical trials on late-stage patients have been modest. Subthalamic deep brain stimulation (STN DBS) is a proven treatment for a selected group of advanced PD patients. The cerebral dopamine neurotrophic factor (CDNF) is a promising therapeutic protein, but its effects in animal models of late-stage PD have remained under-researched. The interactions of NTF and STN DBS treatments have not been studied before. We found that a nigral CDNF protein alone had only a marginal effect on the behavioral deficits in a late-stage hemiparkinsonian rat model (6-OHDA MFB). However, CDNF improved the effect of acute STN DBS on front limb use asymmetry at 2 and 3 weeks after CDNF injection. STN lesion-modeling chronic stimulation-had an additive effect in reducing front limb use in the cylinder test and apomorphine-induced rotation. The combination of CDNF and acute STN DBS had a favorable effect on striatal tyrosine hydroxylase. This study presents a novel additive beneficial effect of NTF and STN DBS, which might be explained by the interaction of DBS-induced endogenous NTFs and exogenously injected CDNF. SNpc can be reached via similar trajectories used in clinical STN DBS, and this interaction is an important area for future studies.

Earlier Intervention with Deep Brain Stimulation for Parkinson's Disease

Neuromodulation of subcortical areas of the brain as therapy to reduce Parkinsonian motor symptoms was developed in the mid-twentieth century and went through many technical and scientific advances that established specific targets and stimulation parameters. Deep Brain Stimulation (DBS) was approved by the FDA in 2002 as neuromodulation therapy for advanced Parkinson's disease, prompting several randomized controlled trials that confirmed its safety and effectiveness. The implantation of tens of thousands of patients in North America and Europe ignited research into its potential role in early disease stages and the therapeutic benefit of DBS compared to best medical therapy. In 2013 the EARLY-STIM trial provided Class I evidence for the use of DBS earlier in Parkinson's disease. This finding led to the most recent FDA approval in patients with at least 4 years of disease duration and 4 months of motor complications as an adjunct therapy for patients not adequately controlled with medications. This following review highlights the historical development and advances made overtime in DBS implantation, the current application, and the challenges that come with it.