The goal of this real world data study is to evaluate the clinical utility of remote patient monitoring solution (using Byteflies' EpiCare@Home with reduced EEG montage and other vital signs) with Dravet and LGS patients (ages 3 and up with the exclusion of adults above weight allowing variable titration) to identify an optimal Fenfluramine treatment.

Patients will wear one or more small portable and medically certified measuring devices. Through these devices, electroencephalography (EEG) signals, as well as electro-cardiography (ECG), heart rate, respiration rate, and physical activity are measured, which allows the patient's physician to detect potential seizures, and thus gain more insights.

Participants will be asked to wear the devices three times at home for remote monitoring periods lasting between 3 and 7 consecutive days. The duration of each monitoring period will be determined by the physician based on the type of epilepsy and the frequency of seizures.

Inclusion Criteria:

• Patients with a confirmed Dravet syndrome or Lennox-Gastaut syndrome diagnosis who are eligible for Fenfluramine.
• Patients for which the neurologist decided to prescribe Fenfluramine as a relevant treatment approach and who have not been prescribed Fenfluramine before.
• Patients or caregivers should be able and willing to maintain a seizure diary e.g. using a digital seizure diary.

Exclusion Criteria: Patients who

• Have been diagnosed with or are suspected to have life-threatening conditions that could result in immediate danger;
• Need to undergo an MRI scan or cardiac defibrillation;
• Have an active implanted device such as a pacemaker, defibrillator, or vagal nerve, or brain stimulator;
• Are unable to provide written informed consent, either directly or via a legal guardian.
• Have known allergy or skin-sensitivity to the materials used in the Byteflies Adhesives
• Are between 0 and 3 years of age;
• Are above weight allowing variable titration
• The patient is on any medication that would be contra-indicated for use with Fenfluramine at the execution of the study eg. LP352 (bexicaserin), loracaserin, monoamine-oxidase inhibitors, SSRIs, SNRIs, tricyclic antidepressants or other serotonergic agonists or antagonists (antipsychotics).
• Have a prescribed concomitant use of Stiripentol
• Have any other condition or finding that would compromise the safety of the participant or the quality of the data, or otherwise interfere with achieving the objectives.
• A history of cardiovascular or cerebrovascular disease, aortic or mitral valve regurgitation diagnosed by echography
• Patients/caregivers who have only reported/detected non-motor seizures