Focal Cortical Dysplasias (FCDs) are neurodevelopmental disorders that represent a major cause of early onset drug-resistant epilepsies with cognitive and behavioral impairments, carrying a lifelong perspective of disability and reduced quality of life. Despite a major medical and socio-economic burden, rationale therapeutic strategies are still under debate. Surgical removal of the epileptogenic brain area (Epileptogenic Zone) is the most successful treatment, yet it fails to control FCD-associated seizures in as much as 40% of cases. Precise definition and complete resection of the Epileptogenic Zone are the main determinants of outcome. In current practice of French centers, up to 80% FCD-patients require an intracranial EEG (icEEG) recording to accurately define the epileptogenic zone. However, the indications for icEEG in MRI-visible FCD remain empirical and are essentially based on expert opinion.

Inclusion Criteria:

• Adult or pediatric patient suffering from drug-resistant focal epilepsy;
• Age more than 2 years old;
• Brain MRI suggestive of FCD or normal;
• Standardized presurgical evaluation available including medical history, scalp video-EEG, 3T MRI, FDG-PET, Neuropsychological tests;
• Inpatient in one of the participating centers for recording seizure during long term scalp video-EEG and / or SEEG-monitoring;
• Resective surgery with a minimal post-operative follow-up of 12 months;
• Histopathologic evidence for FCD or non-pathologic findings (normal histology or mMCD type II).
• Patient, parents or legally representative who have given written informed consent to allow the study data collection procedures.

Exclusion Criteria:

• Brain MRI suggestive of another type of lesion;
• Difficulty to read or understand French, or inability to understand the information;
• Pregnant or breastfeeding woman;
• Subject under judicial protection.
• Other lesion discovered on histological examination;
• FCD type 3, dual pathology, ambiguous or unavailable neuropathological findings
• Lack of longitudinal pre- and post-surgical follow-up.

Adult or pediatric (Age more than 2 years old) patients attending tertiary epilepsy center for presurgical evaluation of refractory focal epilepsy compatible with FCD