First experiences with multiple bilateral insertions of a newly developed microcatheter-compatible endovascular electroencephalogram electrode for humans with epilepsy

Identifying epileptogenic zones non-invasively is challenging due to signal interference by the scalp and skull, necessitating invasive methods like subdural recordings and stereoelectroencephalography. Recent microcatheter advancements suggest that a microcatheter-compatible endovascular EEG (eEEG) device could overcome these barriers. We developed a thin, flexible eEEG electrode, the EP-01, for use with current microcatheters. The EP-01, comprising a platinum electrode and alloy wire coated with an electrically non-conductive polymer, was inserted via the jugular veins under local anesthesia. The EP-01 electrodes were planned to be placed in six locations: bilateral transverse sinuses, bilateral cavernous sinuses, and the anterior and posterior superior sagittal sinuses. We conducted a first-in-human study demonstrating the feasibility and efficacy of the EP-01electrodes in simultaneously recording intracranial EEG signals from multiple brain locations. The EP-01 electrodes were successfully placed as planned, except for one, without complications. Simultaneous eEEG and scalp EEG recordings were performed during a Wada test to evaluate efficacy and safety. The eEEG recorded alpha waves and slow-wave activity during propofol administration, corresponding to scalp EEG findings, with amplitudes 3-4 times higher. Post-procedural assessments confirmed cranial vessels' patency and absence of complications. The EP-01 successfully recorded EEG signals at multiple locations in the human brain using an endovascular approach. Compared to scalp EEG, the present approach seems to have the potential to record higher-amplitude EEG. However, the study was limited to short-term recordings without epileptic discharges. Further investigations, including long-term placement, are thus needed for seizure recordings and safety evaluations.