EP 27 - Parkinsonism and Related Disorders

🎙️ We’re back with the twenty-seventh episode of Parkinson Weekly, hosted by Prof. Bas Bloem.

In Episode 27, Prof. Bloem explores an intriguing and under-researched question in Parkinson’s disease: can temperature influence symptoms?

Inspired by a 2024 study published in Parkinsonism and Related Disorders by Nahid Mohammadzadeh & Joseph Friedman the episode examines how exposure to cold may worsen tremor in people with Parkinson’s disease.

Drawing on both clinical observations and emerging evidence, Prof. Bloem discusses how nearly one-third of patients with tremor reported worsening symptoms in cold conditions—often independent of shivering—while warmer environments may offer relief for some individuals.

The episode also reflects on earlier research, including findings from Prof. Bloem’s own “holiday survey,” which suggested that many patients experience symptom improvement in warmer climates, though responses can vary significantly.

Importantly, Prof. Bloem highlights the limitations of current evidence—small sample sizes, self-reported data, and a lack of objective measurements—while emphasising the potential clinical relevance of temperature as a modifiable factor.

Finally, the episode calls for a more personalised, holistic approach to Parkinson’s care, encouraging patients and clinicians to consider environmental factors such as temperature, and urging researchers to further investigate this overlooked dimension of the disease.

Articles can be found here: https://www.prd-journal.com/issue/S1353-8020(24)X0006-1 & https://www.researchgate.net/publication/364544026_How_vacations_affect_Parkinson's_disease

Have a question you’d like Bas to answer in a future episode? Email us at parkinsonweekly@gmail.com – we’d love to hear from you.

Transcript

SPEAKER_00 0:01

Er is something heel strijd over Parkinson's geheim. Er zijn veel mensen in mijn kliniek die vertellen dat als het warm uitzien. En ik heb even in mijn kliniek die emigreden naar country met een warmer klimaat. Een recente studie is een nieuwe light on this by looking at whether cold exposure tremor. It's a big mystery. You want to hear more? This is episode 27 of Parkinson Weekly. So you think you've heard it all, and here it is: the effect of temperature on the symptoms of Parkinson's disease. It's something that I have heard in my clinical practice quite often, but it's barely researched until a group in 2024 published a lovely paper entitled Winter Cold Exposure often Increases Tremor in Parkinson's Disease. It's a paper published in the journal Parkinsonism and Related Disorders. The first author was Mohammed Sade, and I hope I pronounced that correctly. And Joe Friedman from Brown University was the senior author on the paper. And I thought it was a lovely and interesting study because it touches upon something that you see and hear in your clinical practice, and you wonder: is it real? Is it a spurious observation? Is it an important lead? Yes or no? So in the introduction, the authors mentioned the fact that they too heard this phenomenon quite often in their clinical practice, that people felt that their symptoms were better when they were in an environment with warmer temperatures. They discussed two prior papers that looked at seasonal variations in Parkinson's symptoms. And indeed, in one study, tremor was worse in winter, but the other study found no seasonal variation. What they did not mention, but which is relevant for this topic, is a paper that my own group published in Movement Disorders Clinical Practice in 2022, and it was entitled How Vacations Affect Parkinson's Disease. And interestingly, we did this study not because of temperature, we did this study because we were interested in altitude effects. We were interested in the question whether traveling to high altitudes where there is thin air led to improvements in symptoms. But in order to keep people blinded, we called it the holiday survey, and we just generally asked people about how they felt while traveling to certain holiday destinations in a very open label fashion. And quite interestingly, even though the primary focus of the study was not at all on temperature, 64% of the individuals who reported an improvement on vacation, 64% of those improvers reported a beneficial influence of warmer temperatures. It was not universal. There were also some individuals, 11 in the study in total, who reported a worsening of symptoms, particularly when they were in excessively warm temperatures. So it's not a one-size-fits all, but again, there was a hint in our holiday survey study that warm temperatures did something good for at least some people with Parkinson's, although it was not universal and it was deleterious for certain others. And just as a side note, we did confirm our suspicion that for some folks, and again, this was not consistent, traveling to high altitudes were beneficial. I'll just give you one quote: recently I moved to Colorado. I love to hike in the mountains. The result is a complete, albeit temporary, disappearance of all my symptoms. And another chap said, the first time my tremor noticeably improved while we ascended in the Trans-Siberian Express without me noticing. I'm considering moving to high altitude permanently. Anecdotes that we are now taking to the test in further research. That's for different episodes of Parkinson Weekly. Let's focus on the temperature effect here. So, what Joe Friedman and his colleague did is they asked 151 consecutive persons with Parkinson's in their practice about the effects of cold temperatures. Out of those 151, 90 had a resting tremor in the office. And they simply asked people, does your tremor change when you go out in the cold? They did not ask the opposite question, which you could say is a bit of a shortcoming, but anyways. And if people did report a change, then they went on to ask them if the tremor worsened or improved in the cold. So the opening question is: was there a change in your tremor? Then they said, Did it get better or did it get worse? Which I liked because then people are more blinded. And if it worsened, they asked people, oh, is it just shivering? You know, which I think is a fair thing to ask. What type of tremor increased, resting tremor, postural tremor, and whether their other symptoms also worsened, which again I think is a fair question because you want to know is it a tremor-specific effect or is it a more generic change in your Parkinson condition? Now, quite interestingly, among the 90 people who had a tremor, 23, so just under one-third, reported an increase of their tremor with cold. Five of those only had a worsening of tremor when they were shivering. But 12 out of the 23 had increased tremor even without shivering. Three had it in both conditions, and one was unsure. It was in particular, in most cases, an increase in resting tremor, and more sporadically an increase in postural tremor, and sometimes in both. So quite interesting. And they also asked people about any change in other symptoms. Thirteen reported no change. Just one noted a concurrent worsening in speech, and four reported increased rigidity and slowness. So in about five there was a more widespread worsening beyond tremor, but for thirteen it was really a tremor-specific worsening in cold. Only one subject in the whole group reported that tremor decreased in the cold. So it didn't change for some, the majority, it worsened in about just a little bit under one-third, and there was one individual where it decreased in the cold. So I think there is something happening here. They looked at an association with age, and interestingly, the negative effect of cold was largest in younger people. So the older the people got, the less the increase was when people were exposed to cold. They also looked at medication effects and could find no correlation to the cold effect. So it's a lovely study because it raises awareness for a hitherto largely neglected yet potentially highly relevant topic, namely the influence of temperature on Parkinson's symptoms. So I think the greatest strength is that it touches upon a new dimension of Parkinson's that has hitherto been poorly studied, yet it could have potential relevance. It's not a perfect study. It was a small sample, relatively small sample, particularly if you looked at the folks with tremor. It's probably a biased population. It's a center of excellence for Parkinson's. Doesn't attract your run-of-the-mill average Parkinson patients. The questionnaire that they used to ascertain the effects of cold was not properly validated. They did not systematically search for all types of temperature influences. I would have loved to see how heat affected Parkinson's, modest temperature increases, real excessive heat, as we showed in our holiday survey. And of course, this was only self-report. There were no, for example, objective tests of tremor while people were going through different changes in environmental temperature. So, what is the impact for tomorrow? Well, if you are a person with Parkinson's listening to this podcast, maybe you want to ask yourself how this relates to your own situation. What is happening to your tremor when you go out and about in the cold? What happens in your tremor during summer? What happens when you travel to warmer climates? And really begin to think about and start to see modulating tremor as part of a what I often call holistic approach to Parkinson management. This is not final, of course, and I wouldn't say I would recommend or prescribe moving to a warmer climate, but I do think we are living in a time of personalized precision medicine. And if this Parkinson Weekly resonates, if you think, heck, this is something I recognize and this is consistent, and I'd noticed this all along, even without knowing, then perhaps you could build this into your repertoire to improve your situation. If you're a clinician, take your patients seriously, take their answers seriously, and ask your patients about this, and think with your patients about possible solutions. Again, if this is a consistent finding on a personal end of one basis, I would take it seriously and would think with your folks how to best incorporate temperature control, climate control, as part of the holistic approach to Parkinson's. And finally, if you are a researcher listening to Parkinson Weekly, roll up the sleeves and study this further. I think there's something out there. We have no idea how temperature affects Parkinson's disease, symptoms. I think, based on the seasonal variation study that I mentioned, our vacation study, the anecdotes that Joe Friedman and others and we are seeing in our clinical practice, and now this new survey study on cold and tremor. I think there's something out there, but we need to understand it more fully. We need to begin to understand mechanisms and eventually apply it on a personal basis to optimize quality of life for people with Parkinson. I hope you enjoyed listening to this. I thought it was an interesting study. This was episode 27 of Parkinson Weekly. Look forward to seeing you again next week.

SPEAKER_01 12:10

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