The report is a product of the VA/HSR Evidence Synthesis Program.

Comparative Effectiveness of Focused Ultrasound Therapy for Movement Disorders

Takeaway: High intensity focused ultrasound (FUS) therapy, a noninvasive technique for targeted tissue ablation, has been shown to be effective for treating a variety of health conditions, including movement disorders such as essential tremor (ET), Parkinson's disease (PD), and dystonia. Magnetic resonance-guided focused ultrasound (MRgFUS) combines high intensity FUS therapy and magnetic resonance imaging to target and destroy tissue without damaging surrounding structures or requiring surgery. This review found that for ET, bilateral deep brain stimulation compared to unilateral MRgFUS may provide better improvement in tremor-related outcomes and quality of life. For PD and dystonia, there was insufficient evidence to assess the comparative effectiveness of MRgFUS. There was also insufficient evidence to make conclusions about the use of MRgFUS in patients with dystonia. Research is needed on the comparative effectiveness and safety of MRgFUS, including studies that compare target locations, laterality, sides, and different treatments.

High intensity focused ultrasound (FUS) therapy, a noninvasive technique for targeted tissue ablation, has been shown to be effective for treating multiple health conditions, including common movement disorders such as Parkinson’s disease (PD), essential tremor (ET), and dystonia. Magnetic resonance-guided focused ultrasound (MRgFUS) combines high intensity FUS therapy and magnetic resonance imaging to target and destroy tissue without damaging surrounding structures or requiring surgery. MRgFUS is approved by the FDA for the treatment of ET and PD, but there is limited information about the comparative effectiveness of MRgFUS to other treatments, and minimal evidence about other comparative factors such as anatomical target or unilateral versus bilateral treatments. Its effectiveness in treating other movement-related conditions is also uncertain.

In response to a request from VA Parkinson's Disease Research, Education, and Clinical Centers, the Evidence Synthesis Program (ESP) Center in Providence, RI, reviewed the available evidence on the comparative effectiveness and safety of MRgFUS for movement disorders. To identify relevant articles, ESP investigators searched PubMed, EMBASE, Cochrane, and ClinicalTrials.gov from inception to August 26, 2024; hand-searched reference lists of systematic and non-systematic reviews; and consulted content experts. Eligible studies were comparative studies only for ET and PD and single group study designs for other movement disorders.

Summary of Findings

Of 3,856 records screened, 14 studies were included in this review along with 22 systematic reviews or meta-analyses. Of the 14 studies, nine included patients with ET, one included patients with PD, and four included patients with dystonia.

Essential Tremor:

• Bilateral deep brain stimulation compared to unilateral MRgFUS may provide better improvement of tremor-related outcomes and quality of life (low confidence).
• Bilateral compared to unilateral treatment may provide better improvement of tremor-related outcomes (moderate confidence).
• There were no differences in functional outcomes between unilateral and bilateral treatments (low confidence).

Parkinson's Disease:

• There was insufficient evidence to make conclusions about the use of MRgFUS in these patients.

Dystonia:

• Single group studies showed improvements in several outcomes of interest, but there was insufficient evidence to make conclusions about the effectiveness of MRgFUS in patients with dystonia.

Implications

MRgFUS has emerged within the last decade as a viable and noninvasive alternative for the treatment of movement disorders. As MRgFUS establishes itself in the treatment of movement disorders, there is a need for well-designed randomized controlled trials that compare MRgFUS to other treatments and enhance understanding of the effect of different anatomical targets, as well as longer-term outcomes of unilateral and bilateral procedures.

Limitations

MRgFUS has already been proven to be effective for ET and PD compared to sham or placebo. For these conditions, the ESP team focused only on studies that provided comparative results based on treatment, target location, or laterality, which limited the literature base. In addition, this review includes only studies that intentionally and prospectively targeted different treatment locations in the brain. Finally, for conditions other than ET and PD, the ESP investigators included single group studies, which do not provide information on how treatment compares to other treatments including usual medical management.

Future Research

There is a need for comparative studies that compare target locations, laterality, sides, and different treatments. Future nonrandomized comparative studies should adjust for confounders such as patient characteristics and availability of treatment options and infrastructure. In addition, future studies should document when and how treatment adjustments are made and consider approaches to control for adjustments in the analysis. Lastly, future studies should aim to compare treatment outcomes based on patient characteristics that might be important for treatment, such as skull density ratio.

Citation:

Rieke K, Rudolph J, Mai HJ, et al. Comparative Effectiveness of Focused Ultrasound Therapy for Movement Disorders: A Systematic Review. Washington, DC: Evidence Synthesis Program, Health Systems Research, Office of Research and Development, Department of Veterans Affairs. VA ESP Project #22-116; 2025.

To view the full report, go to https://www.hsrd.research.va.gov/publications/esp/reports.cfm. (This report is available via Intranet only.)

How can VA leadership work with the ESP? Nominations for systematic review topics may be submitted to the program at any time. When you submit a topic nomination form, ESP Coordinating Center staff will work with you to determine the appropriate research approach and ESP product to address your questions of interest. Topics are selected and assigned to an ESP Center based on program capacity and alignment with VA national goals.

This Management Brief is provided to inform you about recent HSR findings that may be of interest. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs. If you have any questions or comments about this Brief, please email CIDER. The Center for Information Dissemination and Education Resources (CIDER) is a VA HSR Resource Center charged with disseminating important HSR findings and information to policy makers, managers, clinicians, and researchers working to improve the health and care of Veterans.

This report is a product of VA/HSR's Evidence Synthesis Program (ESP), which was established to provide timely and accurate synthesis of targeted healthcare topics of particular importance to VA managers and policymakers; and to disseminate these reports throughout VA.

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