The state of vigilance and not antiseizure medication dosage drive variability in interictal epilepsy biomarkers.

OBJECTIVE: During presurgical intracranial electroencephalography (iEEG) investigation, anti-seizure medication (ASM) is typically tapered to record seizures. Interictal biomarkers are critical for epileptogenic zone (EZ) localization. This study examines how ASM tapering and other confounding factors influence the rates and localization accuracy of interictal iEEG biomarkers. METHODS: iEEG data from 19 patients were analyzed during two 24 h sections separated by at least seven days during > 10-day iEEG monitoring. ASM dosage, vigilance state, time of day, seizure proximity, and duration of monitoring were evaluated for their impact on interictal biomarker rates, spatial distribution and localization of the EZ. RESULTS: Biomarker rates, spatial distributions, and EZ localization did not significantly differ between the two 24-hour sections. The state of vigilance emerged as the most significant contributor explaining 22.7 % of the variability. Seizure proximity, time of day and ASM dosage contributed minimally, each accounting for ≤3.7 % of the variability. CONCLUSIONS: The state of vigilance is the most significant determinant of interictal biomarker variability, and exceeds the impact of all other confounding factors regarding biomarker rates, distribution, and EZ localization. SIGNIFICANCE: These findings highlight the importance of vigilance state over ASM tapering, supporting the potential use of interictal biomarkers for EZ localization, regardless of ASM adjustments.

Duke Scholars

Author Birgit Frauscher Neurology, Epilepsy and Sleep