Abstracts

Rationale: Withdrawal of antiepileptic drugs (AED) is necessary to register a sufficient number of seizures in video-EEG (vEEG) monitoring, to evaluate diagnosis and treatments in a subset of patients with drug-resistant epilepsy. In adult epilepsy patients with infrequent seizures, vEEG often lasts several weeks to capture their seizures. Most of them have been treated with multiple AED. Because of the various half-life of AED, the AED withdrawal during only vEEG period tends shorter than the expectation. We provided a specific pre-monitoring admission (PMA) before vEEG to withdraw AED. This report presents the customizing AED withdrawal to capture seizures within max 7 day-vEEG monitoring. Methods: We collected 89 patients with 3 criteria; 1), seizure occurrence = < 3 per month; 2), AED >=2; 3), AED withdrawal was performed during their admission, among126 consecutive patients who underwent vEEG in department of neurosurgery, Hiroshima university hospital between 2011 and 2014. We divided 2 groups of patients due to half-life of AED; group A with phenobarbital (PB, 79-117 hours in adults) and/or zonisamide (ZNS, 50-63 hours in adults); group B with other AED. For all 23 patients in group A, PB and ZNS were completely discontinued during 3~4 day-PMA before vEEG start. Further AED withdrawal was performed during vEEG, depending on the seizure occurrence in group A (Fig.1A). For all 66 patients in group B, AED was gradually, one-by-one, discontinued during both PMA and vEEG periods (Fig.1B). Results: The age at vEEG was 35.5+-15.2 year-old (mean +- SD) in group A and 31.8+-15.2 year-old in group B. The number of AED ranged 2-6 (3.5+-0.9) in group A and 2-5 (2.8+-0.8) in group B. All 23 group A patients and 13 (20%) of 66 group B patients underwent AED discontinuation during PMA (1.2+-0.5 in group A; 1.1+-0.3 in group B) Seizures were equally captured for both groups; (1-13, 3.4+-2.5 seizures; range, mean+-SD) in 22 (96%) group A patients; (1-10, 3.5+-2.2 seizures) in 61 (92%) group B patients. The first seizure started at PMA in 2 (9%) group A patients and 2 (15%) group B patients. The first seizure occurred significantly longer after the start of withdrawal in group A (6.22.0 days) than group B (2.91.3 days, p < 0.01). Status epilepticus occurred in 1 (4%) group A patient and 1 (2%) group B patient during vEEG. Conclusions: The planning of AED withdrawal during PMA succeeded to capture seizures for adult epilepsy patients with infrequent but intractable seizures. The customizing AED withdrawal based on their half-life is necessary to record sufficient seizures during the limited period of vEEG, for diagnosis and treatments of drug-resistant epilepsy. Funding: Not applicable