Abstracts

Rationale: The golden standard of treatment effect in patients treated with Anti-Epileptic Drugs (AED) is patient reported events written in a seizure diary. While the reliability of self-reported events in a seizure diary is known to be low, it is the only measure to assert the number of seizures in the everyday life of the patient. The recent development of an unobtrusive subcutaneous ultra long-term electroencephalogram (EEG) device may challenge this way of asserting the seizure burden. In this case report, we present the superiority of seizure counting from ultra long-term EEG based on the minimally invasive subcutaneous device on a single patient. Methods: A beta version of the UNEEG 24/7 EEG™ SubQ was used to continuously monitor the EEG of nine patients with temporal lobe epilepsy continuously for a period of up to three months. The subcutaneous implant consists of a wire with three electrodes and a coil. An external device powers the implant and stores the data. The external device needs to be charged every second day and can hold up to two months of continuous data.EEG recorded seizure patterns, diary entries as well as AED usage and titration are reported during the 11-week period of continuous monitoring of one patient. Results: There is a large discrepancy between diary-based and EEG-based seizure count (figure 1). The patient reports two seizures in the seizure diary, while 16 seizure patterns are recorded with the device. There is no overlap between seizure days that the patient reports and EEG-detections. Notice that 13 out of 16 seizure patterns occur at the first half of the period during low lamotrigine dosage. Two of the remaining three seizure patterns occur after two days of AED-non-compliance.Figure 1: Top plot indicates lacosamide daily dose, bottom lamotrigine. Red Line indicates EEG seizure pattern with seizure density in yellow. Blue line indicates self-reported seizure. Black indicates actual daily dose. Gray indicates the dose the patient was instructed to take in the first days, when there are no compliance data. It is uncertain when the 75 mg lamotrigine dose stopped in the last week. Conclusions: Ultra long-term subcutaneous EEG is very suitable for seizure counting. It is a minimally invasive method, which accommodates the possibility of unobtrusive recordings in the every-day life of epilepsy patients. Further, based on this case-study, it is likely that ultra long-term EEG increases the power of clinical trials in epilepsy due to a more correct seizure count than has previously been available. Funding: National Danish Science Foundation, UNEEG medical A/S, Zealand Regional Research Council.