An interventional study of Transcranial temporal interference stimulation and Tremor monitoring through Inertial Measurement Units (IMUs) in Essential Tremor, sponsored by University Hospital, Geneva. Not yet recruiting at 1 site in Switzerland. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-01.
Sponsored by University Hospital, Geneva · Not applicable, Interventional, and Other
The goal of this proof-of-concept study is to examine the effects of a relatively new, non-invasive electrical current-based technique, transcranial temporal interference stimulation (tTIS), in patients with Essential Tremor (ET). TTIS is delivered via a Digitimer Ltd. stimulator, the "DS5 Isolated Bipolar Constant Current Stimulator." The method enables targeting deep cerebral structures to selectively modulate neurons. The structure of interest in the present study is the ventralis intermedius (VIM) of the thalamus, which plays a key role in tremor generation in people with essential tremor. Therefore, techniques targeting the VIM nucleus can potentially improve the tremor and the quality of life in the long term, as is the case with MRI-guided high-intensity focused ultrasound (MRgHIFU). Despite its efficiency, MRgHIFU can lead to side effects that could benefit from improved predictive modeling. In our proof-of-concept study, the investigators aim to examine whether tTIS of the VIM nucleus can alter tremor characteristics and, therefore, mimic the effects of MRgHIFU. This work would pave the way for future clinical trials to design prediction tools for MRgHIFU if the investigators can demonstrate the positive impact of tTIS.
Essential tremor (ET) represents one of the most common movement disorders worldwide, with an estimated prevalence of 1 % across all ages, increasing with age. Despite being considered a benign disease, it can nevertheless lead to significant functional impairment. Several drugs, such as beta-blockers, can be used to alleviate the tremor, but they may not be enough to improve the quality of life, and they can cause significant side effects.
The etiology and pathophysiology of ET are not yet fully understood. One pathophysiological hypothesis for ET is a deficiency in cerebellar GABAergic transmission, leading to abnormal oscillatory activity that interferes with motor function. This abnormal oscillatory activity converges on the thalamus, specifically in the ventralis intermedius (VIM) nucleus. Various surgical or disruptive medical techniques can target this nucleus in case of a drug-resistant tremor or drug intolerance.
One such technique is MRI-guided, high-intensity focused ultrasound thalamotomy (MRgHIFU), which results in a long-lasting, significant reduction of tremor in most cases. Despite the MRgHIFU's millimetric precision, the VIM is not directly visible on peri-operative MRI scans. MRgHIFU thalamotomy can also lead to side effects, such as modifications of sensations (paresthesia), speech difficulties (dysarthria), imbalance (ataxia), or even motor deficits (hemiparesis). Therefore, more accurate tools are needed to predict the effects of MRgHIFU.
One promising technique that could help clinicians predict the effects of MRgHIFU is transcranial temporal interference stimulation. This non-invasive neuromodulation technique uses two pairs of scalp electrodes, which deliver two slightly different high-frequency currents (e.g., f1 = 2.00 kHz; f2 = 2.01 kHz). Frequencies in the kHz range are too high to induce an effect on neurons and nerves. Still, due to their difference Δf = f2-f1, they both interfere in the depth of the brain to create a so-called amplitude-modulated envelope with a beat frequency falling in the physiological range (e.g., Δf = 10 Hz). This allows neuromodulation of deep structures-the VIM in this study-and avoids stimulation of the cortical structures at the same time. The investigators will use the Digitimer Ltd. "DS5 Isolated Bipolar Constant Current Stimulator" to deliver tTIS.
The goal of the proposed proof-of-concept study is to examine the effects of tTIS on tremor modulation in essential tremor patients who are candidates for MRgHIFU thermoablation of the VIM, and to compare the impact of tTIS with the "true" effect of tremor reduction after MRgHIFU. The primary outcome will be the change in tremor amplitude (in mm), as measured by Inertial Measurement Units (IMUs) comprising an accelerometer, a gyroscope, and a magnetometer. The secondary outcomes will be other quantitative tremor parameters, such as the frequency, angular and linear acceleration, and power, as well as safety outcomes.
272 studies on the registry are indexed under Essential Tremor; 75 are open to participants now.
This study's planned enrollment of 6 is below the median of 25 across 189 interventional studies indexed under Essential Tremor.
Browse Essential Tremor studies →University Hospital, Geneva is the lead sponsor of 379 studies on the registry; 70 are open to participants now.
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Exclusion Criteria (for both arms):
Only for patients undergoing the tTIS protocol (experimental arm):
for non-invasive brain stimulation:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
In this arm, patients with essential tremor who are candidates for MRgHIFU will undergo the tTIS stimulation protocol before MRgHIFU. The tremor changes will be monitored using Inertial Measurement Units (IMUs) during the tTIS, as well as after tTIS and MRgHIFU.
Device: Transcranial temporal interference stimulation · Other: Tremor monitoring through Inertial Measurement Units (IMUs)
In this arm, essential tremor patients who are candidates for MRgHIFU will undergo only tremor monitoring using Inertial Measurement Units (IMUs) before and after MRgHIFU.
Other: Tremor monitoring through Inertial Measurement Units (IMUs)
We will deliver transcranial temporal interference stimulation (tTIS) via the DS5 stimulator (Digitimer Ltd.) in patients with essential tremor who are candidates for MRgHIFU to examine its ability to modulate the tremor amplitude.
Essential tremor patients candidates for MRgFUS, whether undergoing the tTIS protocol (experimental arm) or acting as controls (control arm), will undergo a tremor quantification through Inertial Measurement Units (IMUs) before, during, and after the stimulation (for the experimental arm), as well as before and after MRgHIFU (both arms).
Tremor amplitude
Tremor amplitude, measured in mm in the 3 axes, using an Inertial Measurement Unit (IMU) secured on the dorsum of both hands of the essential tremor patient.
Time frame: From enrollment to day 1 (D1) after MRgHIFU
Tremor peak frequency
Peak (dominant) frequency of the tremor in Hz
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Frequency Width Half Maximum (FWHM)
Frequency Width Half Maximum (FWHM) in Hz, i.e., the frequency bandwidth where the power spectrum's value is at least half of its maximum value
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Tremor Stability Index (TSI)
Tremor Stability Index (TSI), i.e., the interquartile range of the change in frequency (Δf), indicating the cycle-to-cycle variations of tremor
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Power of the tremor
Power band spectrum, measured in dB, derived from the three-dimensional data of the IMU
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Half-Width Power (HWP)
Half-Width Power (HWP), .i.e., the power referring to the frequency bandwidth where the power spectrum remains at least half of its maximum, calculated as the area under the spectral curve between two vertical straight lines intersecting the rising and falling edge of the peak at half of the peak power (full-width half maximum), in the main frequency band of interest
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Linear acceleration of tremor
Linear acceleration in 3 dimensions (measured in m/s\^2 through the accelerometer component of the IMU)
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Angular velocity of tremor
Angular velocity in 3 axes, measured in degrees per second (°/s), through the gyroscope component
Time frame: From enrollment to day 1 (D1) post-MRgHIFU
Incidence of Device-Emergent (Serious) Adverse Events [Safety]
Only for the experimental arm (tTIS protocol): safety will be assessed through the number of (severe) adverse events (SAEs/AEs) possibly, probably, or definitely related to the study device.
Time frame: From enrollment to day 1 (D1) post-stimulation
Plan to share: Yes — De-identified individual participant data, including demographic data, clinical characteristics, and quantitative tremor assessment data, will be shared. Data will be available upon reasonable request to the corresponding author after publication of the primary results, in accordance with ethical approval and applicable data protection regulations.
Time frame: After publication of the primary results, upon reasonable request.
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