Sean Nagel, MD, Staff Neurosurgeon at Cleveland Clinic talks about essential tremor and how the MRI guided focused ultrasound can help.
Interview conducted by Ivanhoe Broadcast News in March 2019.
What is essential tremor?
NAGEL: Essential tremor is a movement disorder. It is the most common movement disorder in the United States and is very disabling when it’s severe. It interferes with work, eating, drinking, daily activities.
What are the other symptoms besides tremors?
NAGEL: Most of the patients will have tremors with predominantly fine motor skills. So eating drinking, brushing their teeth, applying makeup is when the tremor emerges. Other than these symptoms there are there are not too many other manifestations of the disease.
What causes it?
NAGEL: It’s still unknown exactly what the cause is. But there are specific areas of the brain that we know quite well respond to treatment. We know that these are important relay sites for the production of tremor.
Who is at the greatest risk for having essential tremor? Men, women, is there an age group?
NAGEL: Usually people will notice tremor early on in life. Some people as early as their teens or early 20s. But for most people it doesn’t become very severe or bother them until much later. Most of the patients we see in our practice are usually near retirement age although in some people the tremor becomes severe enough that they need to retire early. But by and large most of the patients that we’re taking care of right now are usually 50s and older.
What are the current treatments?
NAGEL: Most of the time patients will start off with medications or sometimes behavioral modification. In most people however, one of these will work very well for some period of time. But a certain subset of those patients will ultimately become refractory or fail medications. Some people also may develop some side effects from the medications and may seek out other treatments. Typical treatments right now include deep brain stimulation and now that focused ultrasound is approved, we expect that this will also become commonly requested as an option.
When should people seek a specialist if they have a tremor?
NAGEL: Usually when it’s starting to interfere with their life. When they have symptoms that bother them and prevent them from doing things that they enjoy. That’s usually the best time to seek out expert opinion to help manage the disease.. And again, usually it is something that will respond well to medications initially.
You mentioned deep brain stimulation. Can you describe what that is?
NAGEL: For the last two decades or so deep brain stimulation has been the surgical treatment of choice for patients with essential tremor. It involves implanting one or two leads into the brain depending on how severe the tremor is on each side of the body and then hooking it to a small battery pack that is typically placed in the chest wall. The device itself can then be programmed to optimize or customize the control of the tremor.
Could you describe what the MRI-guided focused ultrasound is?
NAGEL: The MRI guided focused ultrasound is an exciting new therapy for patients with essential tremor. The ultrasound device is coupled to the MRI a that measures heat inside the brain to help verify the location of the treatment.
And what exactly does the heat do? Most people think of ultrasound as sort of a simple type of test really. But how is it different in this regard?
NAGEL: The focused ultrasound allows the physicians to target a very specific area of the brain. As you slowly increase the energy over time to this area, you can see of neural tissue within the brain warm up using the MRI. Almost immediately after, we get real time feedback from the patients to see if their symptoms are improving. We incrementally continue to increase the energy that the ultrasound delivers until a permanent lesion is detected on the MRI. From that point on the patient will then have relief of their tremor for a sustained period of time..
And then, is it basically like scar tissue that’s created? And it covers the area that’s causing the tremor?
NAGEL: Correct. This is a really small area of the brain we are treating In fact is very nearly the same target we use for deep brain stimulation. We are intentionally creating a permanent lesion in this case The real advantage to this therapy over other therapies is that we have real time feedback from the patients. Before we use enough ultrasound energy to cause a permanent lesion we see that their tremors have responded.
OK. And then the lesion stops the signals that are causing the tremors?
NAGEL: Correct. There are specific areas within the brain, relay sites for the patients tremor that when are targeted, whether through deep brain stimulation or through a permanent lesion controls the tremor
Let’s talk a little bit about Bill’s case. How was he doing before the surgery? And then how did he do afterwards?
NAGEL: Mr. Purcell had a very severe, disabling tremor that essentially limited him from doing most things that we take for granted. Having a cup of coffee or eating. And this over time became so bothersome to him, that he was willing to undergo a more invasive treatment, like, ultrasound.. we meet as a group to decide if we think that they’ll respond well to the treatment and if they’re suitable candidates. And in his case, he was. After the treatment he had near immediate response.
What were some of the results that you witnessed right after treatment? I know somebody said he was drinking some coffee and drawing.
NAGEL: Yes. That’s right. During the treatment patients are evaluated during each ultrasound or each sonication. And during that time we evaluate their tremor through a number of activities, having them sign their names or draw spiral or hold a cup. And this all happens in real time within the MRI itself. Once we start to see a response and have delivered the final treatment the effect is permanent. And so immediately we could see that he had a significant benefit in his tremor. And was able to hold a cup out without any significant tremor at that time. He was able to write his name and draw a spiral, much better than he was prior to the start of the treatment. At the end of the treatment after he was taken to the recovery room, we were able to give him a cup of coffee, which for the first time in several years he was able to drink without spilling any.
And he’s a big coffee drinker so that was a big moment for him.
NAGEL: Yes. That’s right.
What have the results been so far in general to the ultrasound? And then if you could also talk about any long-term data.
NAGEL: Yes. This is a new therapy that was only recently FDA approved. It has been tested on several hundred people at this point. But while we expect this to be an important device in the treatment of patients with tremor and Parkinson’s tremor, the long-term data is still unknown. There is a chance that in some patients the tremor could recur. In which case, we’re not exactly clear if they’ll be eligible to repeat the treatment. One important feature to note is right now we’re only treating one side of the brain for a patient’s tremor. In the future, this may change. But this is the state of the art right now.
How many other centers across the country are currently using this?
NAGEL: There were several centers that were involved in the initial trial to test the device but they were using it primarily for research purposes during the investigational period. Over the next year or two we expect to see more and more of the focused ultrasound devices throughout the country.
Was Bill part of a trial?
NAGEL: He was not.
Bill had essential tremors, is this also being used for Parkinson’s patients?
NAGEL: It is. It’s also now approved for Parkinson’s related tremor as well.
Is it covered by insurance?
NAGEL: Yes. But I’m not sure about all the details.
What do you think is the future for MRI guided focused ultrasound?
NAGEL: This is still an early therapy. And we don’t know how much this will transform the field. It’s possible that this could eclipse even something like deep brain stimulation in the management of tremor. But it’s just too early to tell. Although, we expect that there will be new indications. In the near future for things, like, pain, possibly psychiatric diseases, epilepsy and even brain tumors.
Is having a procedure like this which is virtually incisionless, is it a game changer for the field or could it be?
NAGEL: We expect that many patients who would not have considered undergoing deep brain stimulation would potentially want to have this treatment because it does not require any incisions. However, we do have to fix a frame to the head in order to hold the head still for the treatment. In addition, patients need to have their head shaved and they need to be off blood thinners to participate.
Is there anything else we didn’t ask that you think is important for people to know?
NAGEL: It’s a hard treatment to describe because it’s a unique treatment that brought together a number of different technologies, the focused ultrasound plus MRI thermometry coupling these two technologies together allowed this to move forward.
It’s really an incredible option for people. Just amazing to see the improvement.
NAGEL: . And there are quite a few patients who for one reason or other aren’t eligible for deep brain stimulation due to maybe other medical problems. Some just aren’t willing to have an implant put in and so for them this ends up being a very good option
END OF INTERVIEW
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