Antiepileptic Drug Withdrawal in Patients with Temporal Lobe Epilepsy Undergoing Presurgical Video‐EEG Monitoring

Abstract

Summary:Purpose: To investigate antiepileptic drug (AED) withdrawal during video-EEG monitoring in adult patients with temporal lobe epilepsy (TLE).Methods: Between 1995 and 1997, 102 consecutive patients with refractory TLE were admitted to the epilepsy monitoring unit for presurgical evaluation. Patients were monitored with ongoing AEDs being rapidly decreased and discontinued in 4-6 days. The monitoring was continued until sufficient numbers of seizures were recorded. Serum AED levels were checked at admission and after the first complex partial seizure (CPS).Results: In all, 89 patients had 429 CPSs (mean, 4.8 per patient), including 156 (36.4%) secondarily generalized. A mean of 153.8 h (16-451 h) was required for completing the monitoring in each patient. Forty-three (48.3%) patients experienced seizure clusters, and eight (9.0%) had generalized seizures that had never occurred or had been absent for years. However, none evolved to status epilepticus. Carbamazepine was the most commonly used AED in 71.9% of patients, followed by valproate and phenytoin. When the first CPS occurred, mean 77.2 h since the beginning of the monitoring, serum levels of these three AEDs were mostly subtherapeutic rather than minimal.Conclusions: Acute AED withdrawal effectively provoked seizures in TLE patients undergoing presurgical video-EEG monitoring. However, nearly 50% of patients had seizure clusters or secondarily generalized seizures. Serum AED levels were mostly subtherapeutic when the first CPS occurred.

Seizure Duration Determined by Subdural Electrode Recordings in Adult Patients with Intractable Focal Epilepsy

“…We used the clinical 4-hour period definition for seizure clustering. The rate of seizure clusters in the present study was similar to that reported in subjects who underwent presurgical evaluations 9,23. The duration of the first seizure in a cluster of seizures (median, 98s; range, 14–246s) was significantly longer than that of non-cluster seizures (median, 89s; range 4–1016s).…”

Effective withdrawal of antiepileptic drugs in premonitoring admission to capture seizures during limited video‐EEG monitoring

“…However, for adult patients with infrequent seizures who were taking multiple antiepileptic drugs (AEDs), a lengthy stay may be required for vEEG monitoring because of the unpredictability of their seizure occurrences. 4…”

“…Previous reports applying AED withdrawal showed 81.0-92.6% diagnostic yield, with one or more seizures confirmed in the monitored adult patients with infrequent seizures. 4,[6][7][8][9][10][11] There were various patterns of AED withdrawal in each institution. Therefore, the vEEG monitoring periods ranged from 1 to 37 days.…”

“…We investigated (1) the incidence of clustering of ≥3 seizures during 4 h; (2) ≥3 seizures during 24 h; 4,6,7,10 (3) unexpected secondarily GTCS in patients who had never presented secondarily GTCS during the previous 5 years; (4) nonconvulsive status epilepticus (NCSE), which we defined as continuous seizure activity without major motor signs, lasting longer than 30 min; 9 (5) convulsive status epilepticus, which we defined as a convulsive seizure lasting longer than 5 min or when consciousness was not regained between two consecutive convulsive seizures; 14 and (6) significant injury with intracranial bleeding or bone fracture of any part of the body.…”

“…Yen et al 4 monitored serum levels of CBZ, VPA, PHT, PB, and PRM at the time of first seizure during vEEG in 89 patients with temporal lobe epilepsy. When the first seizure occurred, the serum level of AED was subtherapeutic, but not at the minimum level.…”