[Invasive EEG for temporal lobe epilepsy: selection of technique]

Non-invasive EEG reveals epileptogenic zone in 70% of patients. In other cases, invasive EEG monitoring is indicated. Various implantation strategies and techniques of intracranial EEG (icEEG) potentially provide different outcomes. Choosing the optimal icEEG technique may be challenging.

To analyze the results of icEEG in adults with temporal lobe epilepsy and to determine the algorithm for selection of optimal invasive EEG technique.

The study included 82 patients with temporal lobe epilepsy who underwent invasive EEG. Effectiveness of invasive EEG was determined by detection of epileptogenic zone and post-resection outcomes. Postoperative results were analyzed throughout more than 6-month follow-up period using the Engel grading system. Statistical analysis was conducted using the Fisher's exact test.

Epileptogenic zone was revealed in 72 (88%) cases. Invasive EEG was supplemented by another modality in 3 (4%) patients. Mean follow-up period after resection was 17 months in 45 patients. Favorable outcomes were achieved in 31 (69%) cases. Statistical analysis showed that identification of epileptogenic zone depends existing of lesion and symptoms of seizures. Selection algorithm for optimal technique of invasive EEG was determined considering own results and literature data.

Invasive EEG results and post-resection outcomes demonstrated favorable efficacy of original algorithm. The last one may be used in decision-making on optimal technique of invasive EEG in adults with temporal lobe epilepsy.