NCT06610877 · University of California, San Francisco
Ultrasound Neuromodulation in Essential Tremor
(UNMET)
What this study is about
This study is being done to test whether low-intensity focused ultrasound (LIFU) (low energy sound waves) cause temporary changes in brain activity and behavior when directed at particular parts of the brain.
View original scientific description
This study is being done to test whether low-intensity focused ultrasound (LIFU) (low energy sound waves) cause temporary changes in brain activity and behavior when directed at particular parts of the brain. By targeting LIFU to the parts of the brain thought to be responsible for essential tremor (ET), and measuring any associated improvement in tremor, the investigators hope to show that LIFU can be a useful tool for studying the brain circuits responsible for tremor and other brain disorders.
Interventions
DEVICE
Focused Ultrasound Neuromodulation - Sham Control
Each ultrasound stimulation protocol will last for 60 seconds, consisting of 4 pulse trains of 5 seconds duration separated by 10 second intervals without stimulation. Across successive stimulation protocols (up to 25/patient) investigators will systematically vary pulse repetition frequency, duty cycle, and acoustic intensity to determine how these parameters contribute to the behavioral effect (transient tremor reduction). Parameters will be shuffled to control for group-level carry over effects. A defocusing lens will be in place during the session to test the difference between focused and unfoucused ultrasound while controlling for non-specific auditory and somatosensory confounds.
DEVICE
Focused ultrasound neuromodulation
Each ultrasound stimulation protocol will last for 60 seconds, consisting of 4 pulse trains of 5 seconds duration separated by 10 second intervals without stimulation. Across successive stimulation protocols (up to 25/patient) investigators will systematically vary pulse repetition frequency, duty cycle, and acoustic intensity to determine how these parameters contribute to the behavioral effect (transient tremor reduction) in each patient. Parameters will be shuffled to control for group-level carry over effects and will include sham (unfocused or off-target stimulation) conditions to control for non-specific auditory confounds.
Primary outcome measures
Reduction in tremor
Time frame: For 3 minutes immediately after the application of each sonication protocol
The investigators will screen ultrasound parameters through repeated sonications within the same session (up to 25, depending on patient response) to determine which parameter set is most effective at reducing tremor in each participant as measured by wrist accelerometers (reduction in tremor power from baseline in the characteristic ET range of 4-12 Hz). Stimulation protocols will consist of 5 seconds of active stimulation followed by 10 seconds of no stimulation repeated four times (total 60 s). After each 60-s stimulation, there will be a delay of 3 minutes, during which the investigators will monitor tremor severity every 60 seconds through quantitative accelerometer recordings. If a change in tremor severity greater than 50% is found in the post-LIFU period compared to the pre-LIFU baseline, the investigators will wait until tremor returns to a level comparable to baseline before proceeding with additional stimulations.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patients with medically refractory tremor scheduled to undergo MR-guided high-intensity focused ultrasound (HIFU) thalamotomy to treat their tremor at UCSF.
Exclusion criteria
- Due to the logistical complexity of performing MRI in patients with MR-conditional pacemakers (need for device and patient monitoring), patients with pacemakers will be excluded from enrollment. All other patients undergoing HIFU thalamotomy for tremor will be eligible for enrollment.
Where
- San Francisco, California
Collaborators
Focused Ultrasound Foundation
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Mar 6, 2026 · Source of record for eligibility and locations