Diagnostic efficiency of monitoring methods of brain bioelectric activity in temporal lobe pharmacoresistant epilepsy

Background. The basis of pre-surgical neurophysiological examinations of patients with pharmaco-resistant structural epilepsy is the method of monitoring bioelectrical activity of the brain, video-electroencephalographic monitoring and, if indicated, long-term invasive monitoring.

Objective. The goal of the study is to estimate the diagnostic efficacy of the methods used for monitoring of the brain bioelectric activity on the basis of longterm results of surgical treatment of patients with temporal structural pharmaco-resistant epilepsy.

Design and methods. The study included 61 patients with temporal lobe pharmaco-resistant epilepsy, who were divided into two groups: performance of video-EEG monitoring only (33 patients) and the additional use of invasive monitoring for the localization of the epileptogenic zone (28 patients). Each group was divided into subgroups depending on the outcome of surgical treatment: patients, in whom seizures ceased (Engel 1) and patients in whom seizures persisted to some degree (Engel 2-3-4). Invasive monitoring with ictal event recording was chosen as the reference method to calculate diagnostic efficacy.

Results. Invasive monitoring was performed as part of the pre-surgical evaluation of patients with temporal lobe pharmaco-resistant epilepsy with a higher sensitivity (72.7 %) and accuracy (82.4 %) than video-EEG monitoring (sensitivity 50 %, accuracy 45.9 %).

Conclusion. In simple monofocal variants of structural epilepsy, video-EEG monitoring has a sufficient level of diagnostic efficiency. The phenomenon of neurophysiological phenotypes convergence is responsible for the reduced diagnostic efficacy of noninvasive and invasive monitoring.

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