Deep Brain Stimulation at End of Life: Clinical and Ethical Considerations

Abstract

Deep brain stimulation (DBS) is an implanted neurological device effective in treating motor symptoms of Parkinson disease (PD), such as tremor, rigidity, and bradykinesia. More than 150,000 patients worldwide have been implanted with DBS devices. Questions arise at the end of life concerning how to provide best care for patients with DBS, including its continued benefit or potential complications, yet, no published articles provide guidance for hospice providers regarding the management of DBS devices in end-of-life care. With contributions from hospice physicians, a neurosurgeon, and ethicists, this article provides recommendations to address clinical and ethical challenges in optimizing DBS for patients with PD nearing the end of life.

Introduction

Parkinson disease (PD) is a progressive and incurable neurodegenerative disorder characterized by four cardinal motor symptoms: tremor, rigidity, bradykinesia, and postural instability.^1–3 Medical and surgical treatment options exist to alleviate motor symptoms of PD³ and first-line treatment is usually dopaminergic pharmacotherapy.^2,4 Over time, the benefits of medical management diminish and side effects increase.^2,4

Deep brain stimulation (DBS) has emerged as an effective treatment for motor symptoms of advanced, medication-refractory PD.⁵ DBS involves the surgical implantation of a multielectrode stimulating lead within the brain.⁶ Electrodes are connected to an implantable pulse generator (IPG) typically placed subcutaneously in the infraclavicular area.⁶ Major randomized controlled trials have shown that DBS can improve motor function and quality of life, and reduce the need for levodopa and related medications, mitigating medication-related side effects.^7–10

Since 1997, over 150,000 patients have undergone DBS implantation in the treatment of PD. Beyond PD, DBS is indicated in the treatment of medically refractory essential tremor, dystonia, epilepsy, and obsessive compulsive disorder. It is currently under investigation for use in major depression, chronic pain, stroke recovery, anorexia, obesity, and other neuropsychiatric conditions. While distinct considerations may arise in each application of DBS, this article addresses DBS in the treatment of PD, its most common application. As patients with DBS devices age and approach the end of life, hospice providers will encounter them more frequently. This article uses a case to illustrate pertinent clinical and ethical considerations and offers recommendations for managing DBS at the end of life. Recommendations derive from the experience of a multidisciplinary team at a high-volume DBS center and the expertise of hospice and palliative medicine physicians experienced at managing medical devices as patients near the end of life.

Case Description

The family of a hospice-eligible 77-year-old man with PD who lacks capacity to make his own health care decisions has requested enrollment in hospice. The patient underwent bilateral DBS at age 69 to address worsening tremor and medication-induced dyskinesias (a side effect of dopaminergic treatment). During his presurgical evaluation, the patient shared that his goals in undergoing DBS were to reduce spilling and embarrassment while dining in public, to continue playing with his grandchildren, and to type on a computer so he could continue to manage finances. DBS successfully supported these goals for a number of years. Four years after implantation, both IPGs in his device were replaced due to battery depletion and he continued to experience motor benefits.

The patient developed progressive dementia and entered a nursing home earlier this year. He has been treated for aspiration pneumonia four times in the past three months, has lost weight, and is now unable to feed himself. His motor function has declined due to disease progression. The patient designated his wife as his health care agent in a valid health care power of attorney document and indicated in a living will document that in the event he is in a terminal condition, he would want doctors to stop all life-sustaining therapies.

A chart note from the DBS center indicates that the IPGs will soon need replacement. The patient's family and hospice team wonder what steps should be taken to optimize the management of his DBS device before enrollment in hospice and how best to care for him while in hospice.

Discussion

DBS is distinct from other implantable devices such as implantable cardioverter-defibrillators because it is undertaken purely to improve quality of life, not to prolong life. Below, we discuss issues to consider before hospice enrollment, additional care needs once enrolled, and ethical considerations that may arise.

Optimizing DBS before hospice enrollment

Before enrolling the patient in hospice, communication with his DBS providers may be necessary to assess device hardware functionality and battery life. End-of-life management of DBS devices parallels management of cardiac pacemakers in that low battery levels should prompt a careful evaluation of the device's ongoing value as goals of care evolve. Similar to deactivation of pacemakers, deactivating DBS may increase symptom burden.

DBS uses either rechargeable or nonrechargeable batteries that must be surgically replaced when depleted. Nonrechargeable batteries last approximately two to five years, while rechargeable batteries can last nine years or more. Rechargeable batteries must be recharged for one to two hours per week, but some patients recharge every day. Complete exhaustion of rechargeable batteries may cause premature battery failure. In this patient's case, his first nonrechargeable battery depleted four years after implantation and three years have since passed. Low battery levels noted in his last visit raise concerns about battery depletion.

Since battery replacement requires a small surgery, it is important to evaluate whether the benefits of battery replacement outweigh the risks and costs, with special attention to evolving goals of care. If the battery depletes completely, it is expected that the patient's motor symptoms will worsen, limiting his ability to transfer. The degree to which these symptoms worsen is difficult to predict and must be weighed against the disruption and risks of surgery. When deciding whether it is worthwhile to undergo battery replacement, it may be useful to temporarily deactivate DBS in an “off trial.”

During an off trial, stimulation is deactivated via the remote control device called a “programmer” and the patient is monitored for 24–72 hours for symptom recurrence. Some symptoms may not resume immediately, so caretakers should carefully monitor for changes in motor symptoms and signs of discomfort. During an off trial, anti-Parkinsonian medications may be increased to control symptoms, although many patients with PD are unable to take oral medications in the last weeks of life and these medications may have limited benefit in advanced PD.¹¹ Figure 1 illustrates how an off trial may help determine whether the discomfort and costs of battery replacement are justified by the symptom control DBS continues to provide. Inquiring about experiences in which the device has been accidentally or intentionally deactivated during previous clinical evaluations or procedures may avoid the need for an off trial and the discomfort or suffering it may cause.

FIG. 1.

Protocol for trial off.

Special considerations for hospice care

Hardware complications

External devices such as the patient's programming device and charging equipment should be kept readily available. As with any implanted device, DBS hardware can become infected. Infections of the skin or soft tissue will present as a cellulitis or abscess, with pain, redness, drainage, or fluctuance over the implanted hardware. Soft tissue infections can extend intracranially to cause central nervous system infections. Infection is often progressive without surgical treatment. Finally, implanted hardware can break, either spontaneously or from trauma, and present as a worsening of motor symptoms. Suspected hardware failure can be evaluated noninvasively by the DBS center. Sometimes, symptoms can be relieved by reprogramming the device but often will not improve without surgical intervention. At the end of life, decisions regarding treatment of these complications should be individualized according to the patient's goals of care.

Nursing care

Routine nursing care is appropriate for DBS patients with few exceptions, and specific instructions can always be obtained from the device manufacturer or DBS center. Special attention should be directed to the infraclavicular area where the IPG is placed and to the skin above the wires connecting the IPG to the electrodes in the brain. This area should be monitored for skin breakdown or infection and assessed after falls for laceration or hardware eroding through the skin. Rechargeable batteries also require ongoing monitoring and charging, according to the manufacturer's instructions. Patients usually recharge batteries without nursing supervision. For patients with severe dementia, this should be delegated to family or nursing staff.

Ethical considerations

As part of a patient-centered approach to end-of-life care, hospice care providers should seek to understand a patient's initial motivation for undergoing DBS implantation (or subsequent IPG replacements) as an expression of patient values that may continue to bear upon care decisions at the end of life. Although goals of care are likely to have shifted since DBS implantation, reexamining the underlying values they reflect may be instructive. For example, this patient underwent DBS to reduce embarrassment while dining in public, to interact with family, and to type on a computer. While the patient may not be able to engage in the activities anymore, ongoing management of his tremor and dyskinesias may continue to promote comfort, a sense of dignity, and social interactivity. Even if the patient lacks capacity to make treatment decisions for himself, he may still be able to describe activities he continues to value and this input should be incorporated into goals of care discussions as part of a shared decision-making process.

Requests to discontinue DBS at the end of life may be prompted by battery depletion, new symptom management considerations, or a shift in goals of care. In the context of battery depletion, an off trial before hospice enrollment supports informed decisions about whether battery replacement is needed to provide comfort or achieve other goals of care. Off trials should be conducted only after the trial plan has been carefully explained to the patient and family. Patients lacking capacity to participate in treatment decisions should be provided an opportunity to express assent or indicate dissent. Importantly, off trials should take place under close supervision, with an appropriate amount of time to observe latent effects of discontinuing stimulation while avoiding unnecessary discomfort. Families and caregivers may experience distress in actively turning off the device during an off trial, rather than passively allowing DBS batteries to deplete. However, the decision not to replace DBS batteries should be made intentionally and with good information about whether the device contributes to the patient's comfort.

In rare circumstances, caregivers may consider deactivating DBS as new symptoms develop. Farris et al. address the ethically complex situation of a family and nursing home director requesting deactivation of a DBS device to mitigate impulsivity and other behavioral symptoms secondary to PD dementia.¹² Since well-programmed DBS devices rarely induce significant behavioral side effects and dopaminergic medications may exacerbate impulsivity, deactivating the DBS device is unlikely to be justified under most circumstances. The effects of discontinuing DBS should be weighed against the side effects of pharmacologic treatments that may be prescribed and other alternatives to identify the least restrictive approach to addressing behavioral symptoms.

Hospice providers may seek guidance from family and advance directives in evaluating how DBS continues to support a patient's goals of care and whether DBS can or should be withdrawn at the end of life. DBS generally does not constitute life-sustaining therapy, as the term is defined in advance directive forms, since it is not undertaken to prolong the process of dying or to postpone death. Although there is limited evidence DBS is associated with an increase in long-term survival compared to medical management,¹³ DBS has not been demonstrated to prolong the dying process for patients in terminal conditions. Therefore, unless patients specifically document preferences regarding DBS management, DBS should not be discontinued on the basis of a living will directing health care providers to withhold or withdraw life-sustaining treatment. DBS may instead be considered comfort care, diminishing discomfort by alleviating tremor, rigidity, or medication-related side effects. If DBS alleviates discomfort with a more acceptable balance of side effects compared to other potential comfort measures, this limits any justification for device deactivation and may justify battery replacement in later stages of disease progression.

In this patient's case, an off trial was conducted before hospice enrollment where he developed worsening motor symptoms and distress, despite titration of his anti-Parkinsonian medications. After discussion with his family and the DBS team, it was determined that continuing DBS best respected his goals and values. The patient underwent battery replacement before enrollment in hospice.

Conclusion

This case highlights clinical and ethical challenges in end-of-life care for patients with DBS devices that should be considered before and during hospice enrollment. Before hospice enrollment, hardware condition and battery levels should be assessed. If battery levels are low, an off trial is advisable to determine whether battery replacement is needed to provide comfort or achieve other goals of care. If a patient is already enrolled in hospice, an off trial may still be helpful to evaluate the ongoing benefit of DBS compared to other comfort measures. Consideration for DBS-related values and evolving goals of care is essential to a patient-centered approach to end-of-life care, especially when facing decisions about deactivation of the device. As more patients with DBS devices enroll in hospice and providers gain experience navigating the clinical and ethical considerations discussed, these guidelines should be revisited to reach consensus on best practices.

Author Disclosure Statement

L.R.S. reports funding from National Institutes of Health (NIH) grant number 1F32MH115419–01 during the conduct of the study. A.G.M reports personal fees from Enspire DBS, personal fees from ST Jude, grants from St Jude, grants from Medtronic, and grants from NIH, outside the submitted work. P.J.F., L.J.H., R.V.S., and D.J.H. have nothing to disclose.