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Focused Ultrasound Thalamotomy for Essential Tremor (BEST-FUS Trial)

Waitlist Available
Led By Andres Lozano, MD, PhD
Research Sponsored by University Health Network, Toronto
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
The patient has a primary diagnosis of ET or ET plus confirmed by a movement disorder neurologist
The patient previously underwent a MRgFUS (> 6 months ago)
Must not have
Clinically relevant speech impairment (e.g. impairment of intelligibility)
Clinically relevant gait and/or balance impairment (e.g. wide-based, more than 2 falls/months, wheelchair, walker, cane use)
Screening 3 weeks
Treatment Varies
Follow Up post operative month 1, 3, 12, 24, 36
Awards & highlights


This trial is testing a new treatment for essential tremor, which is a movement disorder. The trial is comparing the new treatment to no treatment, and is looking at side effects, how well it works, and quality of life.

Who is the study for?
This trial is for adults over 18 who have essential tremor and previously had successful MRgFUS thalamotomy on one side. They must want treatment for the other side, with a neurologist-confirmed diagnosis of ET or ET plus, and their quality of life should be affected by the tremor.Check my eligibility
What is being tested?
The study tests if focused ultrasound thalamotomy can safely treat essential tremor in the untreated brain hemisphere. Initially, 10 patients will undergo this procedure; if safe, an additional 40 will join. The main goal is to see how much it improves their tremors after a year.See study design
What are the potential side effects?
Potential side effects include issues related to the nervous system like speech problems or balance difficulties. These will be monitored closely at several points post-treatment up to three years.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
I have been diagnosed with Essential Tremor by a specialist.
I had MRgFUS treatment over 6 months ago.
I am 18 years old or older.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
I have trouble being understood when I speak.
I have trouble walking or balancing, and may use a wheelchair, walker, or cane.
My doctor has advised against me joining this trial.


Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~post operative month 1, 3, 12, 24, 36
This trial's timeline: 3 weeks for screening, Varies for treatment, and post operative month 1, 3, 12, 24, 36 for reporting.

Treatment Details

Study Objectives

Outcome measures can provide a clearer picture of what you can expect from a treatment.
Primary outcome measures
Change in QUEST Score
Patient-based Assessment of Utility
Secondary outcome measures
Gait Assessment (NRS-11)
+8 more

Trial Design

1Treatment groups
Experimental Treatment
Group I: Treatment GroupExperimental Treatment1 Intervention
Participants will undergo a thalamotomy contralateral to their previous treatment with MRgFUS using ExAblate Neuro 4000 device (InSightec Ltd, Tirat Carmel, Israel).

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.
Mechanism Of Action
Side Effect Profile
Prior Approvals
Other Research
The most common treatments for Essential Tremor (ET) include MRgFUS Thalamotomy, Deep Brain Stimulation (DBS), and medications. MRgFUS Thalamotomy uses focused ultrasound waves guided by MRI to create a lesion in the thalamus, disrupting abnormal electrical activity that causes tremors. DBS involves implanting electrodes in the thalamus or subthalamic area to deliver electrical pulses that modulate neural activity. Medications like beta-blockers and anticonvulsants reduce tremor amplitude by affecting neurotransmitter pathways. Understanding these mechanisms helps ET patients and their healthcare providers choose the most effective treatment based on the tremor's severity and characteristics.

Find a Location

Who is running the clinical trial?

Université de SherbrookeOTHER
300 Previous Clinical Trials
69,934 Total Patients Enrolled
1 Trials studying Essential Tremor
50 Patients Enrolled for Essential Tremor
University Health Network, TorontoLead Sponsor
1,492 Previous Clinical Trials
490,025 Total Patients Enrolled
2 Trials studying Essential Tremor
75 Patients Enrolled for Essential Tremor
Andres Lozano, MD, PhDPrincipal InvestigatorUniversity of Toronto
2 Previous Clinical Trials
53 Total Patients Enrolled

Media Library

Magnetic Resonance-guided Focused Ultrasound VIM Thalamotomy (Procedure) Clinical Trial Eligibility Overview. Trial Name: NCT04501484 — N/A
Essential Tremor Research Study Groups: Treatment Group
Essential Tremor Clinical Trial 2023: Magnetic Resonance-guided Focused Ultrasound VIM Thalamotomy Highlights & Side Effects. Trial Name: NCT04501484 — N/A
Magnetic Resonance-guided Focused Ultrasound VIM Thalamotomy (Procedure) 2023 Treatment Timeline for Medical Study. Trial Name: NCT04501484 — N/A
~5 spots leftby Dec 2025