Biomarkers of Response to SEEG Thermocoagulation

Summary

Drug-resistant focal epilepsy is a severe neurological disease that affects one-third of patients with epilepsy. Surgery is the only potentially curative treatment. Intracerebral exploration by stereo electroencephalography (SEEG) is an important step in the surgical pathway. It aims to establish the precise mapping of the epileptogenic network (EZN), including all the brain regions that generate seizures. At the end of SEEG, SEEG-guided radiofrequency thermocoagulation (SEEG RFTC) represents a therapeutic option that may be efficient as a palliative treatment in patients ineligible for resective surgery, or may lead, in some cases, to a definitive effect, avoiding open surgery. The safety and effectiveness of this approach have been established. However, the odds of remaining seizure-free after one year vary greatly between studies, ranging from 4% to 71%. This disparity in therapeutic responses could be linked to the absence of objective criteria for the selection of targets, but also to the existence of mechanisms of action outside of the direct lesional effect. A decrease in SEEG markers of epileptogenicity may predict thermocoagulation efficiency. However, no data are available regarding changes in alteration of the blood-brain barrier (BBB) connectivity, inflammation, or associated molecular changes and their relationship to prognosis.

This study aims to elucidate the mechanisms underlying the clinical effect of SEEG RFTC by studying the changes in electrophysiological (SEEG), structural (ultra-high field MRI), and biological (blood biomarkers of neuro-glio-vascular damage and inflammation, molecular adaptations) markers. They will be correlated with clinical outcome in a prospective cohort of patients with drug-resistant focal epilepsy. As advantages for clinical care, this study will allow selection of RFTC targets based on scientifically validated criteria, and elaboration of predictive scores for therapeutic response in each patient.

The primary objective is to study the predictive factors of response to SEEG RFTC, by correlating changes in BBB permeability with clinical response 3 months after RFTC, in a prospective cohort of patients with drug-resistant focal epilepsy.

Conditions

• Drug Resistant Epilepsy

Interventions

OTHER

Quality of life questionnaires (QOLIE, EFIQUACEE for children), psychiatric questionnaires (NDDIE, GAD-7, PCL-5) at Visit 1 (V1), V5, V6 and V7

This intervention consists in the completion of diverse questionnaires assessing the quality of life of the subject. These questionnaires include: * quality of life questionnaires: QOLIE or EFICACEE for children * psychiatric questionnaires NDDIE, GAD-7, PCL-5 These questionnaires will be performed during V1, V5, V6 and V7

OTHER

Resting state SEEG recording 30min before and 30 min after RFTC

During this intervention a resting state SEEG recording will be performed before and after RFTC. These recordings will last for 30 minutes each.

OTHER

Blood sample at Visit 1 (V1), V2, V4 and V5

Blood samples will be collected at Visit 1 (V1), V2, V4 and V5. 2 tubes of 2 ml EDTA will be collected during these visits

OTHER

SEEG electrodes tissue-traces sample at V3 (during SEEG electrodes ablation)

During this intervention, investigators will collect brain tissue samples on SEEG electrodes during their extraction.

OTHER

Multiparametric 3T MRI with gadolinium at V1, V4 and V5

3T MRI with gadolinium injections will be performed at V1, V4 and V5.

OTHER

Multiparametric 7T MRI at V1 and V5

Patients will undergo 7T MRI at V1 and V5

Sponsors & Collaborators

• CRMBM-CEMEREM

  collaborator UNKNOWN

• UMR 5203, InsermU1191, IGF, Montpellier

  collaborator UNKNOWN

• Aix Marseille Université

  collaborator OTHER

• Assistance Publique Hopitaux De Marseille

  lead OTHER

Study Design

Allocation

NA

Purpose

OTHER

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

12 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-03-01

Primary Completion

2029-01-31

Completion

2029-06-30