We also provide a literature overview of a key structure consistently associated with tremor improvement:
👉 the dentato-rubro-thalamic tract (DRT).

The best DBS outcomes align closely with its trajectory - regardless of target or disorder.

We added extensive supplementary material, including a review on:
👉 What influences outcomes after DBS?

And yes - indeed.

Connectivity between GPi-DBS electrodes and the convergent tremor map explained significant variance in clinical outcomes.

Building on these data, we analyzed two different DBS patient cohorts:

• Parkinson’s disease patients with subthalamic DBS
• Essential tremor patients with thalamic DBS

Outcome maps from each group could explain outcomes in the other.

Disorder-independent. Target-independent.

Another key step was to collaborate with Rick Helmich.

We incorporated a map from the well-known dimmer-switch model of tremor, based on EMG-fMRI:
🔗 academic.oup.com/brain/articl...

Once again, the same core regions emerged:
- Motor cortex
- Motor cerebellum

Three paths. One destination.

We found: the stronger the connection between a DBS site and this lesion-derived network, the better the tremor relief - even across different disorders.

Tremor is a common symptom across many neurological disorders.

But is there a shared tremor circuit across disorders - one that could guide treatment, regardless of diagnosis?

We think: yes.

Our study is out now in @natcomms.nature.com:

🔗 www.nature.com/articles/s41...

🧵 A thread.

Here’s the interesting part:

When we combined both tDCS and levodopa responses in a linear model, they jointly explained a significant amount of the variance in DBS outcomes.

So we asked, in our cohort:
(i) Does the levodopa response predict DBS outcome?
(ii) Does it correlate with the tDCS response?

The trends were there - but in this small sample (N = 10), neither reached significance on its own.

What did we find?

Levodopa improved motor function more when it followed multifocal tDCS than when it followed sham stimulation.

It seems that tDCS may prime the brain’s response to medication.

Luckily, in our cohort, most patients performed levodopa challenges on both days -
once after real tDCS, and once after sham stimulation.
So we took a closer look.

Some of those patients later underwent DBS - and interestingly, their DBS outcomes correlated with how much they had improved after tDCS.

A hint that both may tap into the same underlying network?
We think yes.

In 2024, we published a randomized, sham-controlled, double-blind study showing that multifocal tDCS, when targeted to a specific Parkinson's Disease response network, led to measurable motor improvements.

Publication in Movement Disorders:
doi.org/10.1002/mds....