An interventional study of Intervention 1 and Intervention 2 in Idiopathic Generalized Epilepsy, sponsored by Oregon Health and Science University. Not yet recruiting at 1 site in United States. Open to participants aged 18 Years to 89 Years. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by Oregon Health and Science University · Not applicable, Interventional, and Treatment
The purpose of this study is to find out if magnetic resonance (MRI)-guided high-intensity focused ultrasound (HIFU) is safe and effective for treating medically refractory generalized epilepsy. HIFU is a procedure that delivers ultrasonic waves to brain regions with great precision to remove tissue that may cause problems. HIFU is approved by the Federal Drug Administration (FDA) for treating patients with essential tremor.
This study aims to find out if HIFU can safely reduce seizure burden in patients with medically refractory generalized epilepsy (MRGE) using metrics commonly used in other treatments for epilepsy, and by the change in frequency of convulsive (generalized tonic-clonic) seizures before and after the intervention.
The primary purpose of this study is to evaluate the safety of thalamotomy targeting the centromedian thalamic nucleus (CMN) using magnetic resonance-guided high-intensity focused ultrasound (HIFU), an incisionless, ablative procedure that selectively delivers ultrasonic waves to brain regions with submillimeter precision, which is already FDA-approved for thalamotomy in essential tremor and in practice at many institutions, including that of the investigators. The proposed study aims to determine if ablation of CMN using HIFU can safely reduce generalized seizure burden in patients with medically refractory generalized epilepsy (MRGE) using success metrics commonly used in interventions for epilepsy and by the change in frequency of convulsive (generalized tonic-clonic) seizures before and after the intervention.
Current literature suggests that thalamotomy with HIFU for essential tremor produces minimal and generally transient side effects, while targeted lesioning of CMN with other modalities such as radiofrequency ablation (RFA) produces similarly transient side effects in patients with MRGE. No mortality associated with treatment was reported in any study. Furthermore, the benefits for this patient population from RFA or from deep brain stimulation (DBS) of CMN ranged from 50-98% reduction in generalized seizures as long as 36 months post-operatively. Thus, the investigators hypothesize that HIFU ablation of CMN will safely produce a similar durable reduction in generalized seizure burden for patients with MRGE.
In the proposed study, patients will be evaluated for three months pre-intervention and followed for one year after Intervention 1. The same schedule will be followed by subjects who proceed to receive Intervention 2.
Seizure freedom will be defined according to the International League Against Epilepsy (ILAE) outcome classification scale. The ILAE outcome scale includes six classes of outcome: Class 1 = seizure free; Class 2 = auras only; Class 3 = one to three seizure days/year and auras; Class 4 = four seizure days/year to 50% reduction in baseline and auras; Class 5 = \<50% reduction in baseline number of seizure days to 100% increase in baseline number of seizure days and auras; Class 6 = >100% increase in baseline number of seizure days and auras. Only patients classified as ILAE Class 1 or Class 2 will be considered seizure-free.
This is a proof-of-concept interventional study whose primary aims are as follows:
Primary Aim 1: To characterize the safety of bilateral CMN ablation using HIFU in terms of both somatic and neuropsychological adverse events.
Primary Aim 2: To determine the efficacy of bilateral CMN ablation using HIFU in reducing generalized seizure burden and effect on interictal Electroencephalogram (EEG) anomalies.
35 studies on the registry are indexed under Epilepsy, Idiopathic Generalized; 4 are open to participants now.
This study's planned enrollment of 10 is below the median of 71 across 26 interventional studies indexed under Epilepsy, Idiopathic Generalized.
Browse Epilepsy, Idiopathic Generalized studies →Oregon Health and Science University is the lead sponsor of 696 studies on the registry; 131 are open to participants now.
Of its 52 completed or terminated interventional studies of FDA-regulated products, 39 (75%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Prior disqualifying medical or surgical history:
I. Unstable angina pectoris on medication II. Subjects with documented myocardial infarction within six months of protocol entry III. Significant congestive heart failure defined with \< 40 IV. Subjects with unstable ventricular arrhythmias V. Subjects with atrial arrhythmias that are not rate-controlled c. Patients with severe hypertension (diastolic BP>100 on medication) d. Patients exhibiting any behavior consistent with ethanol or substance abuse e. Patients with history of abnormal bleeding, hemorrhage, and/or coagulopathy f. Patients receiving anticoagulant or drugs known to increase risk of hemorrhage within one month of focused ultrasound procedure g. Patients with cerebrovascular disease h. Patients with brain tumors i. Patients who are not able or unwilling to tolerate the required prolonged stationary position during treatment. The average treatment time (the time from the first scan to allocate transducer position and ending with the last energy delivery) is 1:56 ± 0.41 hrs (Min: 0.48 hrs, Max: 5:54 hrs) j. Patients with unstable psychiatric disease, uncontrolled depressive symptoms, psychosis, delusions, hallucinations, or suicidal ideation
Patients who are not candidates for HIFU.
a. Patients who have an Overall Skull Density Ratio of 0.40 (±0.05) or less as calculated from the screening CT
Subjects with risk factors for intraoperative or postoperative bleeding:
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.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
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.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
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.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
INR, PT and aPTT (clotting tests)
Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.
Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Ten patients will undergo unilateral HIFU treatment of the dominant hemisphere CMN (Intervention 1). Safety follow-up visits will take place at 2-weeks, 1-month, 3-months, 6-months, 9-months, and 1-year post-treatment to assess for persistent clinically relevant adverse events (AEs) and any AEs related to HIFU treatment. A seizure severity assessment will also be performed at these follow-up visits. Seizure freedom will be defined according to the ILAE classification, with only patients in ILAE classes 1 or 2 considered seizure-free. At the 1-year follow-up visit, patients who have not experienced persistent clinically relevant AEs related to HIFU treatment, and who are not seizure-free according to the ILAE classification, will proceed to second-side HIFU treatment of the CMN (Intervention 2) after an additional three-month pre-second-side evaluation. Patients who are seizure-free according to the ILAE classification after unilateral treatment, or who develop clinically relevant ad
Device: Intervention 1
At the 1-year follow-up visit (for Intervention 1 - unilateral HIFU treatment of CMN), patients who have not experienced persistent clinically relevant AEs related to HIFU treatment, and who are not seizure-free according to the ILAE classification, will proceed to second-side HIFU treatment of the CMN (Intervention 2) after an additional three-month pre-second-side evaluation. Patients who are seizure-free according to the ILAE classification after unilateral treatment, or who develop clinically relevant adverse events (AEs) and any AEs related to HIFU treatment, will not undergo second-side treatment and will exit the study after the 1-year follow-up visit.
Device: Intervention 2
HIFU ablation of dominant-hemisphere centromedian thalamic nucleus (CMN), or dominant seizure activity hemisphere
HIFU ablation of contralateral centromedian thalamic nucleus (CMN)
Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability]
Number of participants with device-related or procedure-related serious adverse events (SAEs) such as deaths, hospitalizations, or life-threatening events as assessed by CTCAE v5.0.
Time frame: From enrollment to 1 year following treatment
Seizure Frequency and Severity
Number of participants with decreased seizure frequency or severity as assessed according to the ILAE classification.
Time frame: From enrollment to 1 year following treatment
Plan to share: Yes — IPD will be shared via secure GitHub folder, which will be provided at time of manuscript submission.
Supporting information: Informed consent form
Time frame: Data will be uploaded for each subject following each respective 90 days follow-up until study conclusion.
Access criteria: Principal Investigator and IRB-approved study team members will have access to this information and are able to share with others via password protected link.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Epilepsy, Idiopathic Generalized →
Oregon Health and Science University →