Pseudo-remission in childhood absence epilepsy. Objective assessment of seizure control and the role of ethosuximide

Absence epilepsy is a common form of pseudo-remission, in which patients and observers may incorrectly believe seizures have ceased while paroxysms persist in subtle form. Three primary factors contribute to this phenomenon: the brief duration (typically less than 10 seconds) and indistinct semiology of typical absences; the limited reliability of parental observation (sensitivity up to 43%); and the occurrence of generalized spike-wave discharges without significant clinical manifestations, which are nonetheless associated with fluctuations in wakefulness. Verification of remission requires at least a properly conducted three-minute hyperventilation test with attentional load. Preferred methods for objective assessment include prolonged video-EEG monitoring that registers wakefulness, sleep, and arousal, and, when indicated, intermittent photic stimulation. However, no direct comparative studies have demonstrated superiority of these methods over short-term EEG with adequately performed hyperventilation. Extended EEG monitoring does not substitute for the induction of provoking factors, and functional testing does not obviate the need for sufficient recording duration. The absence of “peak-slow wave” discharges lasting three seconds or longer may serve as a practical operational criterion, as adopted from the CAE study protocol. Data are presented on the proportion of patients free from treatment failure with ethosuximide, valproic acid, and lamotrigine in patients with newly diagnosed childhood absence epilepsy at Week 16 (53%, 58%, and 29%, respectively) and at Month 12 (45%, 44%, and 21%, respectively). The review also describes the mechanism of action of ethosuximide, discrepancies between NICE recommendations and Russian clinical guidelines, dosing considerations, and the need for laboratory monitoring. The clinical benefit of adjusting therapy based on EEG findings in patients with apparent clinical well-being remains unproven.