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International Parkinson and Movement Disorder Society
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Highlights on Tremor Disorders | Congress 2022

October 01, 2022
Series:MDS Congress 2022
Dr. Claudia Testa shares with Dr. Sara Schaefer why she believes in the quickly shifting field of tremor, we should be more open-minded about changes in diagnoses over time.

[00:00:00] Sara Schaefer: Hello, welcome to the MDS podcast as part of the MDS Congress series for 2022, I will be speaking today with Claudia Testa, a professor of neurology at the university of North Carolina at chapel hill and a chair of the MDS tremor study group. Along with doctors, Alfonso Fasano, and Aasef Shaikh. I'm Sara Schaefer from the Yale School of Medicine.

Welcome Dr. Testa.

[00:00:31] Dr. Claudia Testa: Thank you.

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[00:00:32] Sara Schaefer: So just a broad strokes kind of overview as a chair of the MDS tremor study group. I'm interested in what the study group is doing and what kinds of things are on your radar regarding tremor at the moment?

[00:00:45] Dr. Claudia Testa: So I used to listen to this same 2019 podcast. Roger Elly, the prior chair, and I was impressed that while I can hear some frustration from tremor patients especially with the pandemic we still haven't seen any new therapeutics approved for a while.

At the same time, I was really impressed that a lot of the things that he talked about, people really persisted through the pandemic in terms of keeping trials going and even activating new trials in the space. So I see a lot of hope in terms of the number of companies and overall research groups who are working in the space, onboarding new clinical trials, trying to make new progress. In terms of the tremor or study group itself.

Some of its main names are to help develop tools to advance work in tremor and to launch specific projects and understanding tremor better. And understanding treatments better. So the project on the prevalence of loss of benefit and deep brain stimulation for medication refractory tremor, that's led by Alfonso is really getting more up and running now that we're coming into a new phase of the pandemic, and we've just recently launched a validation of a new MDS scale. So an MDS tool that would be available to everybody, a united tremor rating scale, which is an amplitude based severity rating, scale of tremor in all its activation states. So action postural rest across major body areas.

Because I think it's really a way to help us continue to think of tremor across different disorders in terms of as a family of disorders instead of very specific homogeneous things.

[00:02:29] Sara Schaefer: And in that episode that you alluded to from the 2019 Congress, we also discussed the new classification thought process regarding tremor and it's overlap with dystonia. You literally wrote the book on tremor and, I think a lot of that book talks about the quote on quote cousins of tremor and, how we are changing the way that we think about it. Can you talk about that a little bit?

[00:02:58] Dr. Claudia Testa: Yeah. It's something I'm actually really passionate about.

So the tremor study group grew out of the MDS task force, which created the 2018 updated consensus criteria for tremor classification. And while I don't think that that's a very like set in stone criteria, I'm hoping that that's a way for people to keep moving the conversation forward in terms of how to think about tremor.

It really acknowledges this thinking about how there's tremor that we think of as very pure, rhythmic, easy to discern as what we think of as tremor. And then there are these close cousins where most things that are labeled as disorders that have tremor maybe are quite heterogeneous, maybe contain people with these really pure tremors, maybe contain people who are shading more into dystonia or ataxia or one of these close cousins. Pragmatically, they see people adopting this thinking clinically more and more so just as essential tremor is a really concrete example. We've all seen essential tremor of patients where that diagnosis, that clinical diagnosis really held for a long time. But then they develop symptoms they really move them into Parkinson's disease, or they really keep that pretty concrete, essential tremor diagnosis, even if they involve tremor in more body areas or they start developing really clear cut dystonia, whether or not they had subtle dystonia in the beginning.

And eventually, maybe it looks all like a regular dystonic tremor overlaying, a generalized dystonia, or maybe a focal dystonia with tremor in other body parts. Pragmatically, that means we need to think of these tremor patients as not like said it and forget it, but that we're monitoring them over time.

Having an open mind about a clinical diagnosis changing might refocus treatment like different medications or make different choices like talking to the functional neurosurgery group about whether bilateral GPI deep brain stimulation is a better choice instead of VIM deep brain stimulation or ultrasound.

And with all these advances in genetics, this may lead you to think about pursuing a genetic diagnosis in a dystonia or parkinsonisms thing in terms of the tremor book. Just incredibly thrilled it is finally out. There's a hard copy here at MDS. It's out of Oxford University Press Dietrich Haudenberger's the co-editor.

But most of the authors are MDS members and many of them are here. And it really leans into this thinking of the family of tremor. So not just orthostatic tremor, vocal tremor, really interesting work there. And essential tremor, parkinsonian tremor about those cousins from dysonia ataxia to functional tremors.

And it's really been a privileged position to see the amount of new work and advancements across the board, across the whole family of tremors, but also in basic knowledge, pathophysiology, genetics imaging. A lot of new clinical care concepts, both in treating tremor itself, but in other issues facing tremor patients that are common across tremor patients.

And I think there's been a lot of acknowledgement. This is actually a really at tractable field to work in with a lot of new thinking in both basic research and in clinical care that can really be leveraged, especially with these collaborations and thought processes across things that we used to think of as a very distinct movement disorders.

[00:06:16] Sara Schaefer: Are there any particular studies or pathways of research that you are particularly excited about with regards to tremor diagnosis treatment, pathophysiology, or otherwise?

[00:06:31] Dr. Claudia Testa: I'm excited about some of the work in what many of us consider to be rare tremors. But I think just maybe under recognized, particularly vocal tremors.

And the crossover between vocal tremors and dystonia, vocal tremor and essential tremor, and also an orthostatic tremor probably a rare population, but a lot of interesting overlaps with apraxias, with other larger disorders and maybe potential in treatment interactions that might intersect with a treatments for freezing of gait.

Although these are quite different entities, just trying to think about novel ways to give people some advancement in handling their symptoms. And then again I think just like in 2019, the more we think about how we can collaborate with people who come at things from a very dystonia focused mindset versus people coming things from a very tremor focused mindset, I think we're gonna make a lot more progress already I'm seeing clinical trials that acknowledgement that tremors are heterogeneous disorders. So how we can enrich clinical trial populations as well as use this new thinking to make progress in basic science is really interesting to me.

[00:07:40] Sara Schaefer: Looking at more of a spectrum.

[00:07:42] Dr. Claudia Testa: Yeah.

[00:07:43] Sara Schaefer: Well, thank you very much for this overview.

[00:07:45] Dr. Claudia Testa: Thank you.

Special thank you to:

Claudia Testa

Professor of neurology
University of North Carolina at Chapel Hill
Chair, MDS Tremor Study Group

Sara Schaefer, MD 

Yale School of Medicine

New Haven, CT, USA

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