Epilepsy is the most common chronic neurological disorder in the world, affecting more than 50 million people worldwide. Approximately 35% of patients with epilepsy are refractory to all available antiepileptic drugs. Drug-resistant epilepsies are often partial or focal. Patients with drug-resistant focal epilepsy suffer from an increased risk of death, primarily due to seizure-related fatalities, in comparison with the general population. The only therapeutic option for this form of epilepsy is the surgical removal of the region of the brain responsible for seizures, called the epileptogenic zone (EZ). This requires the precise localization of the EZ based on a comprehensive pre-surgical evaluation of patients.