Clinical Research Directory

Inclusion Criteria: * Drug-resistant epilepsy indicated to VNS based on clinical decision. * Drug-resistant epilepsy is defined as a failure of adequate trials of two tolerated, appropriately chosen, and used antiepileptic drug schedules (whether as monotherapy or in combination) to achieve sustained seizure freedom (Kwan et al., 2010). * Age ≥ 18 years * Availability to record 20 minutes of EEG with photic stimulation, hyperventilation, and eye-opening/closing according to the pre-defined protocol. * Availability of seizure diaries at least three months before VNS implantation OR reliable information about seizure frequency at least three months before VNS implantation * The ability of a patient/family member/caregiver to record seizures precisely into seizure diaries OR the ability of a patient/family member/caregiver to report seizures precisely different ways. * In cases with very high seizure frequency (several seizures per day), it is acceptable to report only the days without any seizures. Exclusion Criteria: * The indication and planning of resection brain surgery as a treatment option for drug-resistant epilepsy. If a patient clearly demonstrates his refusal of resection surgery, he/she can be included in the study. * The presence of psychogenic non-epileptic seizures which cannot be reliably distinguished from epileptic seizures by a patient/family member/caregiver. * The presence of other condition which can resemble epileptic seizures which cannot be reliably distinguished from epileptic seizures by a patient/family member/caregiver. * Metabolic condition or other diseases, in which the increase of seizure frequency is expectable. * The inability of a patient to take regular visits which are required for VNS parameters settings or the study * Life expectancy shorter than two years