The objective of this multicentre study is to collect preoperative, intra operative, early, short, intermediate and mid-term(one years) on the related clinical complications and functional outcomes of market-approved Alcis products to demonstrate safety and performance of these devices in a real-world setting.

Outcome data collected from this study will provide the basis for Post-Market Surveillance (PMS) reporting, Clinical Study Report (CSR), Clinical Evaluation Report (CER) on Alcis devices and support peer-reviewed publications on products performance and safety.

Inclusion Criteria:

• To be included, patients must be:

• 18 months to 65 years

• Patient with drug-resistant and disabling focal epilepsy

• Informed and willing to sign an informed consent form approved by EC / For minors: if one of the parents cannot consent within the timeframe provided by the protocol, then only one parent's signature is required

• Affiliation to the social security or foreign regime recognized in France

• For prospective inclusion: Patient considered for SEEG exploration as part of pre-surgical assessment of epilepsy

• For ambispective inclusion:

  • Must have undergone an SEEG exploration with one ALCIS device before the date of the initiation visit
  • Follow-up visits (at least 12-month) must be prospective
  • Must have complete information available for each completed visit (demographics, preoperative information, implantation information, device details) *.

Exclusion Criteria:

• • Not able to comply with the study procedures based on the judgment of the assessor (e.g. cannot comprehend study questions, inability to keep scheduled assessment times)

  • Any medical condition that could impact the study at investigator's discretion (e.g. allergy…)
  • Pregnant women (contraindication to SEEG exploration)
  • Adult subject to legal protection measure
  • Skull thickness inferior at 2 mm

The patient treated by Depth Coagulation Electrode is drug-resistant epilepsies patient.