The Epios early feasibility study aims to explore the uses of novel sub-scalp lead devices in the detection of epileptic seizures. Epios leads are inserted subcutaneously through dedicated tunneling toolkits and have been designed for continuous EEG recording in inpatients.

This clinical investigation is part of a stepwise program to validate the entire Epios system and it starts with the validation of the Epios leads alone in this two steps study.

According to the state of the art, epilepsy is defined as the spontaneous recurrence of seizures at random intervals. When epilepsy is drug refractory, management plans rely entirely on seizure self-reporting. However, it is now established that self-reports of seizure burdens are inaccurate. The reasons for this are multiple, but important ones include the fact that seizures can affect brain regions involved in awareness and memory, and that epilepsy patient can also have persistent cognitive deficits, so they do not recall having a seizure. EEG caps are the standard tool for monitoring brain waves, but this technology is typically used for less than an hour and rarely can be managed for a period of a week or so because of the need for continual technical interventions, like reapplying electrodes to the skin. Thus, there is no way to fill the gap in the ability to obtain monitoring of EEG for weeks, months or longer.

Given the unmet need for the objective monitoring of epileptic seizures in ambulatory patients, innovative solutions are under development.

The Epios device under investigation in this study consists in novel sub-scalp leads implanted between the scalp and the skull through an insertion tunneling toolkit for EEG monitoring in short-term conditions.

This clinical investigation is part of a stepwise program to validate the entire Epios system and it starts with the validation of the Epios leads alone in step 1 and step 2.

Step 1 is an intra-operative step only, where a 10-minute long EEG recording is performed using the Epios leads, after the patient has undergone general anesthesia for his/her clinically-indicated brain surgery. The study material is removed before skin closure and end of anesthesia.

Step 2 is an inpatient, short-term step, where, following clinically-indicated surgery for brain electrode implantation, the participants will stay in a continuous care unit. Clinical care and study recordings (with Epios subscalp leads) will be carried out in parallel. The Epios leads will remain implanted for the same length of time as the clinical electrodes: clinical EEG workups in epilepsy last one week at the clinical trial hospital, rarely two weeks, virtually never longer. In adherence to this approach, the implantation period of the investigational electrode in step 2 will be less than twenty one days (< 21 days).

Steps 1 and 2 will take 12 to 18 months in total. First participant-In is planned in January 2021 for step 1 and last participant-In is planned in July 2022.

Inclusion criteria:

• Age ≥ 18 years
• Informed Consent as documented by signature
• Neurosurgical patient, i.e. patient under surgical care who will undergo one of the following specific procedures:
• Step 1: Patient in the operating room undergoing clinically indicated brain surgery either for resection (e.g. tumor), cortical mapping (including awake) or intracranial electrode implantation
• Step 2: patients with pharmaco-resistant epilepsy hospitalized in the epilepsy monitoring unit (EMU) for the purpose of intracranial EEG monitoring

Exclusion Criteria:

• Patients with increased risk of infection
• Pregnant or breast-feeding women
• Severe neuropsychiatric disorders
• Severe cognitive problems: the patients need to be able to understand instructions and provide consent
• Chronic headache disorders, such as migraine and related disorders, as well as trigeminal neuralgia
• Medical conditions contraindicating cranial surgery (e.g. skin disorders causing poor wound healing, blood or cardiac disorder requiring chronic anti-coagulation, osteomyelitis, active systemic infection, haemorrhagic disease, diabetes, hepatitis, any documented allergy to implantation material)
• Other chronic, unstable medical conditions that could interfere with subject participation
• Existing scalp lesions or skin breakdown
• Scalp infections
• Implanted neurosurgical devices that are incompatible with Epios leads, which may include DBS leads
• Subjects who are allergic to the anaesthetics used in the implantation