Ultra‐long‐term subcutaneous home monitoring of epilepsy—490 days of EEG from nine patients

Abstract

ObjectiveTo explore the feasibility of home monitoring of epilepsy patients with a novel subcutaneous electroencephalography (EEG) device, including clinical implications, safety, and compliance via the first real‐life test.MethodsWe implanted a beta‐version of the 24/7 EEG SubQ (UNEEG Medical A/S, Denmark) subcutaneously in nine participants with temporal lobe epilepsy. Data on seizures, adverse events, compliance in using the device, and use of antiepileptic drugs (AEDs) were collected. EEG was recorded for up to 3 months, and all EEG data were reviewed visually to identify electrographic seizures. These were descriptively compared to seizure counts and AED changes reported in diaries from the same period.ResultsFour hundred ninety days of EEG and 338 electrographic seizures were collected. Eight participants completed at least 9 weeks of home monitoring, while one cancelled participation after 4 weeks due to postimplantation soreness. In total, 13 cases of device‐related adverse events were registered, none of them serious. Recordings obtained from the device covered 73% of the time, on average (range 45%‐91%). Descriptively, electrographic seizure counts were substantially different from diary seizure counts. We uncovered several cases of underreporting and revealed important information on AED response. Electrographic seizure counts revealed circadian distributions of seizures not visible from seizure diaries.SignificanceThe study shows that home monitoring for up to 3 months with a subcutaneous EEG device is feasible and well tolerated. No serious adverse device‐related events were reported. An objective seizure count can be derived, which often differs substantially from self‐reported seizure counts. Larger clinical trials quantifying the benefits of objective seizure counting should be a priority for future research as well as development of algorithms for automated review of data.

Circadian Rhythms and Epilepsy: A Suitable Case for Absence Epilepsy

“…Those studies confirmed previous observations regarding a presence of stable 24-h but also longer rhythms in epileptic seizures and interictal epileptiform discharges (IEDs). These rhythms varied with respect to the location of the epileptic focus as well as among individual patients (65)(66)(67)(68)(69)(70). Recent studies in humans and in rat models showed stable recurrence of seizures with regard to the phase of the circadian and multidien rhythms pointing toward endogenous mechanisms of such periodicities in epileptic phenomena, coregulation, and interrelationship between seizures and IEDs (67,71).…”

A new era in electroencephalographic monitoring? Subscalp devices for ultra–long‐term recordings

“…The SubQ was used to record EEG in healthy subjects 29 as well as to detect clinically relevant electrographic seizures in epilepsy patients, showing high reliability and tolerance. 32,33 The device comes with dedicated software for automatic seizure detection and EEG visualization. The device is CE-marked, and multiple clinical trials are ongoing.…”

“…Prospective tolerance and safety data specific to subscalp EEG come from a single trial. 33 No serious adverse device-related events occurred, and the patients generally found the device easy to use, although this was only collected anecdotally. Minor annoyances were reported, such as difficulty with simultaneously wearing glasses, occasional nightly disconnections, and the necessity of wearing clothes at night to fix the external device.…”

Past, Present and Future of Home video‐electroencephalographic telemetry: A review of the development of in‐home video‐electroencephalographic recordings

“…Such continuous monitoring systems may be enhanced by novel technology to continuously record EEG using ultraminiaturized subscalp EEG systems. 31 Continuous monitoring addresses several potential needs for people with epilepsy, including creating an objective and automated seizure diary, with the potential to overcome concerns about patient-reported diary inaccuracy 32,33 and creating a seizure alarm for carers. Furthermore, continuous monitoring of EEG opens the possibility of seizure forecasting, 32 which may be immensely valuable.…”