Maximizing the Potential of Deep Brain Stimulation and Focused Ultrasound

Benjamin Walter, MD

Deep brain stimulation (DBS) has become one of the most effective treatment options for patients with Parkinson disease, yet awareness and use of the procedure remains low. Benjamin Walter, MD, has been at the forefront of this procedure, urging patients and physicians within the community to learn about it and utilize it more.

More recently, focused ultrasound technology has made a splash for the treatment of essential tremor, and may also be an option for patients with Parkinson disease. Walter shared how focused ultrasound may be a treatment option for patients who are no longer eligible for DBS, ans the procedure is less invasive.

In an interview with NeurologyLive, Walter recalled his personal experiences with DBS and focused ultrasound and how the Parkinson community can raise awareness for future eligible patients.

NeurologyLive: As a leader in DBS, what has been your personal experience with the technology and where do you see it going?

Benjamin Walter, MD: Well, I have a special place in my heart for deep brain stimulation. It's a very effective therapy. It's always been extremely rewarding to work with patients with deep brain stimulation because the moment we turn it on, we can often see so many different changes, sometimes very quickly, other times, progressive improvement over time, but the degree of benefit and the kinds of benefit that we see are very rewarding. It's also a very exciting technology interface where technology is constantly changing. The kinds of innovations that have come to the space continuously evolve; we have now 3 companies making deep brain stimulation products whereas just a few years ago, we only had 1 in this country. A lot of different tools [are in development] as far as directional leads, leads that may be able to sense what's actually going on in the brain and dynamically adjust to that. It's going to continue to change and it's very exciting right now.

With a limited amount of patients eligible for DBS, how can we improve screening measures to broaden the pool of eligible patients?

There is a limited pool of patients that are eligible for DBS, but it's a lot greater than those who actually do find DBS as a therapy for them. I think the biggest challenge is patients becoming aware that they could be a candidate that could benefit from this therapy, and doctors making the referral for them to get DBS therapy. That's still the biggest challenge that we have. Generally, patients with advanced dementia or other medical problems that preclude them appreciating the benefit from the therapy wouldn't be candidates. Patients who normally get a good response to levodopa and other medications, while that response is getting shorter and shorter and less and less predictable, are typically good candidates for deep brain stimulation. I'd say the only exception to that is some patients have fairly severe tremor with Parkinson that can be very stubborn and not respond to the medications and those patients tend to do well with DBS as well. In fact, it might be their best and only option to get good control of their symptoms.

What can the neurology and greater health care community do to increase awareness for patients who may be eligible for DBS?

Well, I think it's important to mention early just because it's something that patients need to understand the full landscape of what all the different treatment options are that are available to them, and what might be available in the future. I think far too often, patients learn their options early on, know they're fairly limited and things are fine. So to them it doesn't really matter. And then when they do become more advanced, they're not aware of the advanced options that are available for them. By the time they find out about it, it's either too late or it takes time for them to wrap their arms around having a surgical therapy and taking some bigger steps to take control of their Parkinson disease. Letting people know what is available at an early point, even if it isn't time [to consider that therapy], I think is helpful.

What does focused ultrasound offer for patients who may not be eligible for DBS or prefer a less invasive options?

Focused ultrasound is another highly effective therapy currently for tremor and people with Parkinson disease and essential tremor as well. It's not a noninvasive therapy in the sense that there's still a lesion made in the brain; it's a blade therapy. It does have other benefits over DBS because there's no battery or hardware implanted inside the body. It's particularly useful in patients who can't have a surgical procedure due to other medical risks or can’t undergo anesthesia, or for those who are at a high risk for infection and so they can't hold the hardware in their body or they just don't want it in the first place. It can have good benefit on tremor for patients with Parkinson who have other symptoms in addition to tremor, or who will have other symptoms in time. Focused ultrasound in the current target will not help those other symptoms; however there are studies going on right now looking at other targets which may help these other symptoms in the future but not currently.

One of the targets is the globus pallidus, or GPI, which is also a target that's used for DBS. That is being explored experimentally as another target for focused ultrasound, and that would be similar to a pallidotomy, which can be done surgically as well and has been done in the past. We do have experience with pallidotomy, as well as GPI deep brain stimulation. In those patients you can control not just the tremor, but slowness, stiffness, walking, some of the other things that may respond to deep brain stimulation, but it is a unilateral procedure.