A Pilot Study: Focused Ultrasound Thalamotomy for the Prevention of Secondary Generalization in Focal Onset Epilepsy

August 11, 2025 updated by: University of North Carolina, Chapel Hill

A Pilot Open-label Clinical Trial Evaluating the ExAblate Model 4000 Type-1 Focused Ultrasound Thalamotomy for the Prevention of Secondary Generalization in Focal Onset Epilepsy

The purpose of this study is to assess the safety and feasibility of unilateral focused ultrasound thalamotomy in adults with focal onset epilepsy whose medicines are not working well. The ExAblate (ExAblate) transcranial system is the name of the device that will be used to create and send ultrasound waves through the scalp and skull precisely to a small structure located in the center of the brain. This structure is known as the "Anterior Nucleus", and is an important region in the brain that may cause seizures. Safety will be measured by recording and analyzing the frequency of side effects throughout participation. Feasibility will be measured by the ability to create a lesion in the anterior nucleus.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is an open-label prospective intervention study. Ten (10) adults with refractory, focal epilepsy with secondary generalization and able to provide informed consent will undergo focused ultrasound (FUS) thalamotomy. In addition to the diagnosis of medically refractory epilepsy, these patients will need to meet protocol specific inclusion and exclusion criteria. These adults will be screened from the patients being cared for by the epilepsy program at the University of North Carolina at Chapel Hill or referred from elsewhere for enrollment in the study. Initially, 3 participants will be enrolled and followed for 3 months to assess the safety of study intervention. Pending review by the Data and Safety Monitoring Committee (DSMC) and the US Food and Drug Administration (FDA), additional subjects will be enrolled.

This pilot study is being conducted to test the feasibility of this device in order to confirm the design and operating specifications of the device including the ability to identify and accurately ablate the target focus within the Anterior Nucleus.

Safety will be assessed by the frequency of side effects, e.g., new onset of neurological deficits, performance deterioration on neuropsychological testing. Feasibility is defined as the ability to create the desired lesion within the anterior nucleus.

Seizure frequency data will be collected by seizure questionnaire. Quality of life will be measured by the Quality of Life in Epilepsy Inventory (QOLIE-31). Imaging analysis will include a comparison of pre- and post-intervention imaging to identify brain networks associated with clinical outcomes and determine changes in resting-state functional connectivity (assessed by fMRI), as well as in structural (assessed by volumetric T1 and T2 weighted imaging) and microstructural (assessed by diffusion tensor imaging) brain anatomy.

Subject satisfaction with FUS thalamotomy will be assessed by the Epilepsy Surgery Satisfaction Questionnaire (ESSQ-19).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
10

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27599
        • University of North Carolina-Chapel Hill

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Medically refractory epilepsy (≥2 antiepileptic drug failures) deemed disabling by the patient and study investigators.
  • Focal seizures with secondary generalization; with or without primary generalized seizures.
  • ≥ 3 seizures/month on average based on seizure diary of patient's preferred format during the three months prior to enrollment.
  • Stable prescribed epilepsy medication dosages, including stopping or starting medication, for 3 months before enrollment.
  • Anterior Nucleus (AN) identifiable on MRI (structural T1 and T2 images).
  • Willing to maintain seizure diary (3 months before & 3 months after the study treatment).
  • Involved caregiver such as a spouse, family member, or family friend willing to provide reliable care during the study participation.
  • Ability to provide written informed consent to participate.

  • Previous seizure work-up to include:

    1. Home EEG, Epilepsy Monitoring Unit (EMU) video EEG, or intracranial EEG.
    2. Baseline neuropsychological assessment, which includes the Wechsler Advanced Clinical Solutions - Test of Premorbid Functioning (TOPF). Participants obtaining an Intelligence Quotient (IQ) score of ≥70 on the TOPF will be included.
    3. High-definition MRI imaging/Position emission tomography (PET) imaging.

Exclusion Criteria:

  • Have on average less than 3 seizures a month.
  • Have an indwelling vagal nerve stimulator.
  • Have severe untreated neuropsychiatric disorders (e.g., untreated depression or behavioral problems).
  • History of drug or alcohol abuse in the last 12 months.
  • Presence of primary generalized epilepsy (e.g., Lennox Gastaut, drop attacks).
  • Presence of post-infectious epilepsy (i.e., epilepsy from post-herpetic encephalitis).
  • Previous corpus callosotomy (surgery to cut the fibers, called the corpus callosum, that separate each half of the brain).
  • Significant structural brain abnormalities.
  • Unable or unwilling to maintain your current anti-seizure drug dosage for 3 months post-treatment.
  • Pregnant or not practicing birth control methods.
  • History of claustrophobia (fear of closed spaces).
  • Presence of an MRI contraindicated implanted metal or medical device (e.g., pacemaker, metallic joints, or insulin pump).
  • Uncontrolled hypertension or other comorbid conditions (e.g., uncontrolled heart or lung disease).
  • Skull Density Ratio (SDR) <0.4.
  • IQ score of <70 on the Wechsler Advanced Clinical Solutions - Test of Premorbid Functioning (TOPF), a measure conducted as part of baseline neuropsychological assessment.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: high intensity focused ultrasound
Initially, 3 patients will be enrolled and followed for 3 months to assess the safety of study intervention which is unilateral focused ultrasound thalamotomy (anterior nucleus). These data will be reviewed by the Data and Safety Monitoring Committee (DSMC) and the FDA. If approval is granted by the DSMC and FDA, then additional subjects will be enrolled.
Device: High Intensity Focused Ultrasound
Participants will undergo high intensity focused ultrasound surgery utilizing magnetic resonance (MR) imaging guidance using a 3 Tesla scanner.
Other Names:
  • ExAblate Model 4000 Type-1 Focused Ultrasound

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of Participants with Successful Lesion Creation
Time Frame: during the surgical procedure
Feasibility is defined as the ability to create the desired lesion within the anterior nucleus in 80% or more of participants.
during the surgical procedure
Number of Participants with Adverse Events
Time Frame: 12 months
Safety will be assessed by the frequency of side effects, e.g. new onset of neurological deficits, performance deterioration on neuropsychological testing.
12 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in Number of Seizures Reported Across Time
Time Frame: up to 24 months
Captured by participant-recorded seizure questionnaires. Assessed at Baseline, Day 7, Day 30, and months 3, 6, 12 and 24.
up to 24 months
Total QOLIE-31-P Score Across Time
Time Frame: up to 12 months
The Quality of Life in Epilepsy Inventory-31-Problems (QOLIE-31-P) is a survey of health-related quality of life for adults with epilepsy. The QOLIE-31-P is completed by the patient. It contains 39 items, of which a total of 30 are used to make up 7 different subscales. Scores range from 0-100, with higher scores indicating a greater level of functioning and QoL. Assessed at Baseline, and months 1, 3, 6, and 12.
up to 12 months
Change MRI parameter (water diffusivity)
Time Frame: Baseline, (Day 1), Month 3
Water Diffusivity assessed by structural and microstructural MRI in a voxel-wise manner and compared between pre and post operative MRI.
Baseline, (Day 1), Month 3

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of North Carolina, Chapel Hill

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Focused Ultrasound Foundation

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Vibhor Krishna, MD, SM, University of North Carolina, Chapel Hill

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 24, 2018

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 10, 2018

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 24, 2018

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 31, 2018

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 15, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 11, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 22-0350

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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