[Webinar Recording]Advances in Deep Brain Stimulation: 2024 Edition

SHOW NOTES  

DBS: A Brief Overview

Deep brain stimulation is a surgical intervention that involves implanting small, thin wires into specific parts of the brain. These wires deliver electrical signals from a neurostimulator to areas of the brain affected by Parkinson’s. This stimulation helps control some of the cardinal motor symptoms of Parkinson’s, such as tremor, rigidity or stiffness, and bradykinesia (slowness). 

All DBS systems have the same three basic components: the wire, the extension wire, and the battery. A thin wire (also called the “lead” or “electrode”) is connected to an extension wire, which is connected to a battery. The battery, sometimes referred to as a “neurostimulator” or an “implanted pulse generator,” is similar to a cardiac pacemaker and is implanted in the chest.  

Once these components are implanted, a clinician programs the DBS system in order to supply the stimulation/treatment as effectively as possible for the individual person with Parkinson’s.   

When should DBS be explored? 

DBS is not a replacement for medications or a Parkinson’s cure, but it can help you manage symptoms when your medications alone are not giving you the symptom relief you need.

“DBS is an excellent therapy for the right person at the right time,” Dr. Jimenez-Shahed said during the webinar. “And that might be different timing for different people.” She said that generally speaking, DBS can be explored when people with Parkinson’s who have been on medication start experiencing troublesome ON/OFF fluctuations and dyskinesia, or when impactful symptoms like tremor are no longer adequately controlled by medication. 

To determine if a person with Parkinson’s will benefit from DBS, providers conduct several preoperative examinations. One of these is ON/OFF testing, which demonstrates how well a person’s symptoms respond to medications like levodopa. For this test, the person with Parkinson’s refrains from taking their medications for a certain length of time and then undergoes an examination. This allows providers to see what the person’s symptoms look like during an OFF state. Then, the person with Parkinson’s will take their medications, and the providers will re-examine them to see how the medication affects their symptoms.  

“What we generally say is that if a symptom gets better with levodopa–if it seems to be better controlled in the ON state–it is likely that the symptom will be treated with deep brain stimulation,” Dr. Jimenez-Shahed said. “What DBS does is keep people ON longer.” 

The Evolution of DBS 

The U.S. Food and Drug Administration (FDA) first approved deep brain stimulation to treat tremor in people with Parkinson’s in 1997. In 2002, DBS was also approved to treat advanced symptoms of Parkinson’s.  

Dr. Jimenez-Shahed said that the DBS therapy used today is in many ways very similar to what was originally envisioned. However, she also added that there have been many advances–in the devices themselves, in clinicians’ understanding of the technology and the brain, and in providers’ approach to treating people with Parkinsons. Because of these advances, the benefits of DBS continue to increase. 

The Latest “State of Science” on Surgery Technique 

“Awake” versus “Asleep” Surgery 

In 2024, “awake” DBS surgery (when the person with Parkinson’s is not put under complete anesthesia during the procedure) remains more common than “asleep” surgery, but both options are available to people with Parkinson’s. It is becoming more common for surgical centers to to offer both options.

Dr. Jimenez-Shahed explained that which option you undergo may depend on the team you are working with, since individual surgeons have their own preferences and approaches. She said that no significant evidence shows one approach to be better than the other in terms of specific outcomes.  

One Surgery or Multiple 

As Parkinson’s progresses, many people experience symptoms on both sides of their body. To help manage these bilateral symptoms, DBS on both sides of the brain is common.

Whether this includes one single surgical procedure or multiple procedures depends on a variety of factors. Dr. Jimenez-Shahed said that in some cases, the surgeon will implant both electrodes (one in the right brain and one in the left brain) during a single procedure, then wait and monitor for any post-surgical issues to resolve before the surgery takes place to implant the battery. In other cases, a surgeon may implant the electrode in just one hemisphere, then wait before doing a second surgery to implant the electrode in the other side of the brain. Then, a third procedure would take place to implant the battery. 

Adaptive DBS 

A significant DBS advancement that has recently been making headlines is adaptive DBS. This term refers to DBS systems that “adapt” the amount of stimulation at any given moment based on continual monitoring of activity in a person’s brain. Continuous DBS, on the other hand, refers to stimulation in which the device is implanted, programmed, and then runs 24/7.   

Adaptive DBS, as the name suggests, provides more personalized therapy to the user. Dr. Jimenez-Shahed explained it this way: Many people continue taking some Parkinson’s medications even after deep brain stimulation (though often their medication regimen is reduced). If their medications are working and controlling their Parkinson’s symptoms adequately, they may not need as much stimulation from their device. When the medication effects wear off, more stimulation would likely be beneficial. In the continuous stimulation paradigm, the DBS device can’t make those adjustments. It operates the same way whether or not your symptoms are present or not. Adaptive DBS is different; it can provide stimulation only when needed.  

How Adaptive DBS Works 

Researchers and clinicians continue to learn more about brain signals, and their new understanding has led to new and improved methods of DBS. Instead of implanting an electrode that simply delivers electricity, clinicians can now implant electrodes that also record the activity of the brain. As a result, researchers have discovered that there is a particular brain signal (sometimes referred to as the “beta band” or “beta frequency oscillations”) that seems to correlate with symptoms of Parkinson’s.  

Dr. Jimenez-Shahed said the beta band is a particular frequency of a particular neuronal electrical activity that happens in the deep brain structures that DBS is stimulating. When the power of that signal is high, people seem to be experiencing more Parkinson’s symptoms. When the power of that signal is low, it often means that those people are experiencing fewer symptoms. Engineers have been able to devise a control mechanism based on sensing the power in that particular band that can sense increasing Parkinson’s symptoms and increase stimulation in response. It can also recognize when the symptoms seem to lessen and, in turn, can reduce stimulation. 

In short, the new mechanism adapts to the level of this beta frequency oscillation and, based on what an individual’s brain is doing, the stimulation adapts accordingly. 

Adaptive DBS Trials 

Adaptive DBS has been investigated through clinical trials. Dr. Jimenez-Shahed said that there is preliminary data available (though the complete data will not be available until trials are completed) and that, based on early results that are available, it appears that adaptive DBS works as well as continuous DBS in terms of symptom management. Preliminary results also showed that the electrical usage may be a bit less with adaptive stimulation compared to continuous stimulation. Finally, preliminary reports showed that there were no new, different, or unusual side effects during the duration of the study.

On September 17, 2024, a few weeks after the recording of this webinar, researchers involved in a trial of adaptive DBS published an article describing their research.

Programming Advances

Other DBS advancements relate to the programming options available. Two programming updates that Dr. Jimenez-Shahed discussed were remote programming and image-guided programming.   

Remote Programming 

There are different ways you can think about what “remote programming” is. In one sense, remote programming means you are away from your clinician’s office, and you can use your controller to increase or decrease the settings for your device within a set of parameters determined by your clinician. This is a common feature of DBS systems. 

A more advanced remote programming platform allows a clinician who is in their office to connect to a person with Parkinson’s device while the person is in their own home. This allows a clinician to access all programming features of the device just like they would in an office setting.

While this kind of remote programming can work very well in some cases, there are a few issues with it as well. First, it is only possible if both the person with Parkinson’s and their provider have strong internet connections. Second, depending on the symptoms that the person with Parkinson’s is experiencing, it can be difficult for their provider to do a full evaluation and provide the most personalized treatment without being in the same room. 

Image-Guided Programming 

Image-guided programming is another tool that providers have to try to determine the best DBS settings for a specific person. With image-guided programming, clinicians to combine images taken during the preoperative stages with images taken after surgery, which show the brain with the lead or leads in place.

When the programmer studies the merged image, they can see more clearly exactly where the stimulation should be delivered. Because each lead can release stimulation from multiple points, these images help a programmer make adjustments that are tailored to the individual and the brain structure that the clinician wants to target. 

Hardware Advances

All DBS systems now offer a rechargeable battery, which in itself is a noteworthy advancement. In addition, there continue to be incremental improvements in the design of the batteries themselves. They’re now smaller and more efficient, and better estimates are available about battery longevity. The batteries also have longer lifespans than they once did. 

Another significant advancement is that now, people who have had DBS can set their stimulator to MRI mode and get an MRI safely, which for many years was not the case. 

Questions from the Audience 

For the final part of the webinar, Dr. Jimenez-Shahed answered questions from the Davis Phinney Foundation community. Below are those questions and Dr. Jimenez-Shahed’s responses. 

Are there any anatomical reasons a person would be ineligible for DBS? 

There are times when, during the preoperative MRI, the team finds something in the brain that needs to be addressed before the DBS surgery can happen. For example, we once found something like a meningioma where we needed to implant the electrode for DBS, so we had to do the meningioma treatment first and then proceed with the deep brain stimulation. Sometimes, there can be reasons that have to do with the actual target structure in the brain, and we also have to take into consideration the state of the person’s Parkinson’s and any other medical issues a person may have. 

Are there other factors that may deem a person ineligible for DBS? Is there an age “cut off”? 

We are increasingly understanding that there’s a risk/benefit analysis that needs to be considered beyond just a specific age-based cut-off. We know that as people age they can experience other medical conditions, and there can be other things that could make it hard for them to undergo a deep brain stimulation surgery. So we are thoughtful and cautious in our approach, but that does not necessarily mean we would preclude somebody from DBS just because of an age reason.  

The one thing that we give another like a major consideration to is cognitive status–meaning thinking and memory. Most centers require DBS candidates to undergo a neuropsychological assessment, which is a really careful, detailed assessment of all the different brain functions. Not just the motor parts of the brain where we can measure things like tremor and rigidity and bradykinesia, but also things like thinking, planning, executing, attention – all kinds of different brain functions. I we see that somebody is experiencing a lot of difficulty in multiple different brain regions or as a result of different brain functions and they meet criteria for dementia, we have to be particularly careful about doing brain surgery because we know that these individuals may have a higher risk for more complications or further declines after the surgery.  

Can DBS affect speech?

It can, depending on where the electrodes are placed. However, as advancements continue to be made (including the advancements discussed today, such as brain sensing and image-guided programming, and the fact that the electrodes allow us to “steer” the current in certain directions), clinicians can move away from areas that cause speech problems. 

What does the research say about DBS for balance issues? 

This gets back to the conversation about which symptoms improve with medicines. If your balance is clearly better when you’re ON, then chances are that your balance will be improved with DBS, at least in the beginning. However, it’s important to remember that DBS is not a cure for Parkinson’s. It’s not preventing Parkinson’s from progressing. It’s another tool that we have to help control the symptoms. And some symptoms that tend to be particularly hard to manage over time relate to balance and gait. These will continue to change, unfortunately, as Parkinson’s progresses, and they can be difficult to capture control of simply with deep brain stimulation adjustments. 

Does DBS impact sleep? 

There are a number of different sleep issues that people with Parkinson’s may experience. What I see a lot in my work–and what I think the literature also supports–is that people do sleep better after DBS. That may be a result of better control of motor symptoms. DBS may keep them from wearing OFF in the middle of the night, or waking up with tremor, or experiencing other symptoms that interfere with sleep. I think there is evidence, and certainly a lot of anecdotal reports, that people sleep better after DBS. 

Is there a benefit to having DBS earlier during someone’s time living with Parkinson’s? How late is too late to consider DBS? 

There’s a window of opportunity, and that window might open at different times for different people. This window usually is when a person with Parkinson’s begins to experience troublesome ON/OFF fluctuations and dyskinesia.

When does that generally happen? That, too, will vary from person to person. What is currently recommended from the standpoint of how early to do DBS, is that a person should have been living with Parkinson’s for at least four years, and they should be having these types of fluctuations and dyskinesias that are bothersome to them. That’s actually a fairly open statement. It doesn’t say that the dyskinesias have to be this bad; it doesn’t say that ON/OFF fluctuations have to occur this often or have to be that bad. It just has to be troublesome to the person with Parkinson’s. This is part of what we try to lay out when we are doing those preoperative evaluations. 

As far as whether people do better when they’re younger: in general, younger people have fewer other kinds of medical issues, and they generally don’t have as many of the potential Parkinson’s issues that are harder to manage with deep brain stimulation. So the opportunity to benefit could be better the earlier you have DBS. But that doesn’t mean to do it so early that you haven’t given an adequate trial to medications. It’s still critical to do a risk/benefit analysis.   

Does DBS preclude future surgical treatments such as gene therapy or stem cell therapy? 

The thing we’ve always said about deep brain stimulation is that it is implanted hardware, and such implanted hardware can be taken out. So the reversibility of a deep brain stimulator surgery is definitely there. So if such a treatment were to become available that requires that there not be a deep brain stimulator in place, then it becomes an individual risk/benefit analysis about whether it’s worth it to take out a stimulator in order to get the new procedure.  

Can you add leads based on advancing symptoms? Would there be a need to do that? 

It can be done. Usually if we’re talking about doing that, it’s because somebody has had particular difficulty getting symptoms controlled but we are certain that the DBS is doing something, and we don’t want to lose the effect that it does have. We just want to be able to add some additional benefits that are not being obtained. So this is certainly possible, but maybe not a norm. It should not be the first approach to dealing with symptoms that aren’t adequately treated.  

There is a kind of fairly standard algorithm in the approach to troubleshooting a situation where a person with DBS feels like they’re not getting a good response, or getting the response that they would like, or if they’re having symptoms that are not well controlled. Those may include things like completely reprogramming the device. It might include things like getting imaging in order to make sure that the electrode is in the right place. It might be just going through the whole story again and making sure everyone on the team understands the person’s unique Parkinson’s experience and symptoms. All of those considerations should be made first. And, if after that there is reason to believe that adding an electrode might be beneficial, then that can be considered. 

If one programmer can’t find an optimal program for symptoms and side effects, is it okay to ask for another expert opinion? 

It’s really important for you to feel confident in the treatment that you’re getting. And if you feel like there are questions, it is well within your rights to ask for another opinion. Sometimes people may ask for another opinion and find different solutions. Sometimes they may ask for another opinion and find that what’s being done is the best that can be done. So if asking for another opinion gives you confidence in your treatment one way or the other, I think it is an important aspect to pursue.  

What is the most exciting potential advancement in the field of DBS technology coming down the pipeline? What do you see for the future of this field of surgical treatment? 

There are a couple of things I am super excited about. One, the possibility of adaptive DBS. I think we’ll learn a lot about how DBS can work, how it can help people, and how it can help people in a better way. 

I think we are learning a lot about these brain signals. This particular version of adaptive DBS rests on that one particular brain signal that we’re talking about. But there’s a whole lot of research going on looking at other brain signals that might be present and what that might indicate about a person’s particular Parkinson’s.  

One of the things we’re doing at our center is looking very carefully at the nonmotor symptoms of Parkinson’s. I think it’s a really intriguing possibility–that even though we focus so much on the motor symptoms with deep brain stimulation, that we could possibly do a better job of addressing the nonmotor symptoms as well. I think that’s a really exciting possibility because if we can be a little bit more comprehensive in how DBS can help, I think that may also convince a lot more people to consider the therapy. 

Additional Questions from the DPF Community 

A few members of the Davis Phinney Foundation community sent in questions that weren’t able to be answered during the webinar. Below are those questions, along with brief responses and additional information. 

I have had DBS surgery on my right side, and now Parkinson’s has progressed to my other side. How successful is a second surgery on the left side? 

This depends on the individual and their particular symptoms and response to treatment, so it is advisable to talk with your care team about the possibility. Many people have had electrodes implanted on both the right and left sides of the brain with good success. One factor to consider is whether you are experiencing are any health issues that you weren’t experiencing when you had your initial surgery or surgeries. 

Does DBS work for people who have MSA or other parkinsonian syndromes?  

DBS as a therapy for MSA and other Parkinsonian syndromes is generally not recommended at the present time.   

What if someone is likely to get a pacemaker? Does the location of the DBS battery change, or can it be in the same area as a pacemaker? 

In our 2021 Q&A with Dr. Jimenez-Shahed, she said that there are many people with Parkinson’s who have both pacemakers and deep brain stimulators in place. Usually, the DBS battery is placed on the right side of the chest when this is the case. The pacemaker itself does not create any interference with the stimulation being provided, but there are some situations where a pacemaker may interfere with the brain sensing that is possible with certain DBS devices. It may also pose challenges with obtaining adequate brain imaging if that is ever required.  

As long as specific precautions are taken, cardiac device implantation is likely to be safe in people who have had DBS. A 2016 study reported that it is “essential to keep both devices in separate compartments at a safe distance of more than six inches with appropriate programming parameters to avoid interference between the devices.” This paper also highlights case studies where people have had pacemakers relocated successfully due to new devices and/or negative interactions between DBS devices and cardiac pacemakers. 

How does the surgeon decide what type of battery to use? 

Making the choice between fixed-life implantable pulse generators (IPGs) and rechargeable IPGs depends on a number of factors. Typically, fixed-life batteries are maintenance-free, while rechargeable batteries require recharging. However, rechargeable batteries generally have a much longer life, as long as 15 years in some cases. The surgeon will take into account the person with Parkinson’s comfort level with technology and lifestyle when determining what kind of battery to use. For example, if a person is concerned about forgetting to recharge their sysytem’s battery or does not feel comfortable being responsible for its frequent recharging, a fixed-life battery might be more appropriate.

Be sure to talk with your care team about your preferences when it comes to rechargeable or fixed-life batteries. While there may be some limitations as to which type of battery you get based on the facility, the surgeon performing the surgery, and your insurance, it’s important to advocate for yourself in all conversations about your care.  

ADDITIONAL RESOURCES 

Deep Brain Stimulation (DBS) Hub  

Advice About Deep Brain Stimulation from Davis Phinney Foundation Ambassadors 

When to Start Learning about Deep Brain Stimulation 

[Webinar Recording]: A Talk with a Movement Disorder Specialist and Neurosurgeon about Deep Brain Stimulation (DBS) 

Helen Brontë-Stewart Interview about Adaptive DBS

Article about “Awake” DBS Procedures from Yale