EMIRE (EEG Monitoring in Rare Epilepsies) – Ultralong-term subcutaneous EEG monitoring in drug-resistant epilepsy and DEE: results of the first Italian multicenter experience and comparison with the literature.

Objective: One of the main challenges in epilepsy management is objective seizure counting. Innovative subcutaneous electroencephalographic (EEG) systems allow continuous cerebral monitoring in home conditions; however, its feasibility and clinical utility in complex patients remain unclear. This study investigates whether ultralong-term SubQ EEG improves seizure documentation and disease monitoring in adult and adolescents with drug-resistant epilepsy (DRE) and developmental and epileptic encephalopathies (DEEs), comparing the reliability and tolerability with findings reported in the existing literature. Methods: EMIRE is a prospective, multicenter and interventional study conducted through four Italian third level epilepsy centers. 19 patients affected by DRE, including cases of DEE, were recruited across the centers and implanted with 24/7 SubQ EEG device; seizures detection was carried out by EpiSight algorithm, and all recordings were examined by expert neurophysiologists, while patients and caregivers kept seizure diary for the whole study duration. The primary endpoints included device’s tolerability and its impact on patient’s clinical management. Secondary outcome was to evaluate EpiSight’s feasibility compared to patients’ seizure diaries, using expert EEG review as benchmark. We conducted a literature review and identified 49 articles on subcutaneous EEG epilepsy monitoring published between 2019 and 2026. Following screening, 15 eligible studies (117 patients) reporting the clinical use of subcutaneous EEG for seizure recording were included. All studies evaluated the 24/7 SubQ EEG system (Uneeg Medical). We confronted our data with the one reported in the literature. Results: Data from 11 males and 8 females were analyzed, with mean age of 31.5 years (range 14–57), presenting with focal (57.9%), generalized (15.8%), and combined epilepsy (26.3%), including cases of DEE. A total of 51,336 hours of SubQ EEG were recorded, with a mean device utilization of 81.37% (range 36–98%). Six adverse events were reported, all resolved without implications, yielding a 100% tolerability rate (no patient discontinued SubQ EEG). A total of 3889 seizures were collected, 33.97% detected by EpiSight (1321), while the remaining 66.03% were determined thanks to expert operator review. Patient detection in seizure diary was significantly lower, with only 805 seizures (20.70%) reported in seizure diaries. Conclusions: Our study showed device tolerability and usage rates comparable with previous studies extending the use of SubQ EEG to a wider epilepsy spectrum with intellectual disability and DEEs. Our findings show that in this patients’ population the phenomenon of seizures underreporting is even greater respect to literature data. Significance: This first experience of SubQ EEG in patients with DRE and DEEs expand the use of the device for epilepsy management in fragile epilepsy populations with good tolerability and safety.