Cortical Excitability Assessment Using Paired Pulses

Cortical Excitability Assessment of Pharmacoresistant Focal Epilepsy Using Direct Electrical Stimulation During Stereo-electroencephalography

The identification of the epileptogenic zone (EZ) during pharmacoresistant focal epilepsy presurgical assessment frequently requires intracranial recordings like stereo-electroencephalography (SEEG). Cortical direct electrical stimulation (DES) is commonly used during SEEG for functional mapping or to induce seizure.

However, the recording of seizures is sometimes insufficient to circumscribe the EZ and development of new biomarkers is necessary.

The cortex within the EZ is thought to be hyperexcitable. The "paired pulses" paradigm, using transcranial magnetic stimulation (TMS), allows determining the hemispheric cortical excitability level. The investigators hypothesize that paired pulses DES during SEEG could provide useful information for EZ identification.

Inclusion Criteria:

• Age above 18 years old
• Pharmacoresistant focal epilepsy patients undergoing a stereo-electroencephalographic recording
• Provide written consent to the study after receiving clear information
• Be a beneficiary or member of health insurance plan

Exclusion Criteria:

Patient with contraindication for MRI scanning

• Pregnancy
• Prohibition on participation in other research, apart from any other non-interventional research