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

Area of Science:

• Neurosurgery
• Epileptology
• Neurophysiology

Background:

• Non-invasive electroencephalography (EEG) identifies the epileptogenic zone in 70% of epilepsy cases.
• Invasive EEG (icEEG) is crucial for cases where non-invasive methods fail.
• Optimal selection of icEEG techniques remains a challenge due to varied implantation strategies.

Purpose of the Study:

• To analyze the outcomes of icEEG in adult patients diagnosed with temporal lobe epilepsy (TLE).
• To develop and validate an algorithm for selecting the most effective invasive EEG technique.

Main Methods:

• Study included 82 adult patients with TLE undergoing invasive EEG monitoring.
• Effectiveness was assessed by identifying the epileptogenic zone and evaluating post-resection outcomes.
• Outcomes were analyzed using the Engel grading system over a >6-month follow-up; Fisher's exact test was used for statistical analysis.

Main Results:

• The epileptogenic zone was successfully identified in 88% (72/82) of patients.
• Favorable post-resection outcomes (Engel grade I-III) were achieved in 69% (31/45) of cases with a mean follow-up of 17 months.
• Identification of the epileptogenic zone correlated with the presence of lesions and seizure symptoms; a selection algorithm was derived.

Conclusions:

• The developed algorithm demonstrated favorable efficacy in guiding the selection of invasive EEG techniques for TLE.
• This algorithm can assist clinicians in decision-making for optimal invasive EEG strategy in adult TLE patients.