ArticleEpilepsia2023
Quantifying trial-by-trial variability during cortico-cortical evoked potential mapping of epileptogenic tissue.
Article in Epilepsia, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers, 1 of them a synthesis that pooled it.
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Who cites it
12 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Methodologies to detect cortico-cortical evoked potentials: a systematic review.Frontiers in human neuroscience · 2025Pooled it
- Corticocortical evoked potential amplitude is altered by cortical stimulation in epilepsy.Epilepsia · 2026Article
- Optimization of cortico-cortical spectral response analysis parameters for seizure onset zone localization.Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology · 2026Article
- Regional excitability, not epileptic pathology, drives stimulation-evoked interictal spike increases.medRxiv : the preprint server for health sciences · 2026Article
- Intrinsic and extrinsic connectivity of the seizure onset zone at rest and during stimulation.medRxiv : the preprint server for health sciences · 2026Article
- The Physics and Physiology of Electrical Stimulation of the Brain.Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society · 2025Article
- Article
- Can electrical stimulation replace spontaneous seizures in epilepsy surgery?medRxiv : the preprint server for health sciences · 2025Article
- Cortico-cortical evoked potentials: Analytical techniques and emerging paradigms for epileptogenic zone localization.Epilepsia · 2025Review
- Mapping the Epileptogenic Brain Using Low-Frequency Stimulation: Two Decades of Advances and Uncertainties.Journal of clinical medicine · 2025Review
- Variability of cortico-cortical evoked potentials in the epileptogenic zone is related to seizure occurrence.Annals of clinical and translational neurology · 2024Article
- Predictive modeling of evoked intracranial EEG response to medial temporal lobe stimulation in patients with epilepsy.Communications biology · 2024Article
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Authors and funding
11 authors.
Funding
Abstract
objectiveMeasuring cortico-cortical evoked potentials (CCEPs) is a promising tool for mapping epileptic networks, but it is not known how variability in brain state and stimulation technique might impact the use of CCEPs for epilepsy localization. We test the hypotheses that (1) CCEPs demonstrate systematic variability across trials and (2) CCEP amplitudes depend on the timing of stimulation with respect to endogenous, low-frequency oscillations.
methodsWe studied 11 patients who underwent CCEP mapping after stereo-electroencephalography electrode implantation for surgical evaluation of drug-resistant epilepsy. Evoked potentials were measured from all electrodes after each pulse of a 30 s, 1 Hz bipolar stimulation train. We quantified monotonic trends, phase dependence, and standard deviation (SD) of N1 (15-50 ms post-stimulation) and N2 (50-300 ms post-stimulation) amplitudes across the 30 stimulation trials for each patient. We used linear regression to quantify the relationship between measures of CCEP variability and the clinical seizure-onset zone (SOZ) or interictal spike rates.
resultsWe found that N1 and N2 waveforms exhibited both positive and negative monotonic trends in amplitude across trials. SOZ electrodes and electrodes with high interictal spike rates had lower N1 and N2 amplitudes with higher SD across trials. Monotonic trends of N1 and N2 amplitude were more positive when stimulating from an area with higher interictal spike rate. We also found intermittent synchronization of trial-level N1 amplitude with low-frequency phase in the hippocampus, which did not localize the SOZ. SIGNIFICANCE: These findings suggest that standard approaches for CCEP mapping, which involve computing a trial-averaged response over a .2-1 Hz stimulation train, may be masking inter-trial variability that localizes to epileptogenic tissue. We also found that CCEP N1 amplitudes synchronize with ongoing low-frequency oscillations in the hippocampus. Further targeted experiments are needed to determine whether phase-locked stimulation could have a role in localizing epileptogenic tissue.
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