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Updated: May 21, 2026
A Multimodal Imaging- and Stimulation-based Method of Evaluating Connectivity-related Brain Excitability in Patients with Epilepsy
Published on: November 13, 2016
Corticocortical evoked potential amplitude is altered by cortical stimulation in epilepsy
Bethany J Stieve1, Aaron F Struck1, Dillon Scott1
1Department of Neurology, University of Wisconsin, Madison, Wisconsin, USA.
Objective:
Neurostimulation is an established therapy for drug-resistant epilepsy, but optimizing stimulation parameters remains a major challenge. Corticocortical evoked potential (CCEP) amplitude may serve as an immediate biomarker of neurostimulation effects, enabling rapid parameter optimization. This study was undertaken to determine whether changes in CCEP amplitude reflect immediate neurostimulation effects.
Methods:
We conducted a prospective study in 17 patients undergoing stereoelectroencephalographic monitoring. Each cortical site received randomized 5-s stimulation trains at low (7 Hz) and high (100 Hz) frequencies, preceded and followed by 30-s 1-Hz trains to evoke CCEPs. We analyzed 1210 pre-/posttreatment CCEP pairs using nonparametric tests and linear mixed-effects modeling.
Results:
High-frequency stimulation produced significantly greater reductions in CCEP amplitude than low-frequency stimulation (median change: -1.6% vs. -.02%, p = .002), independent of total charge and epileptiform activity. These effects persisted for minutes to more than an hour and were most pronounced within the seizure onset zone. In contrast, low-frequency stimulation caused greater reductions in the mesial temporal region.
Significance:
Relative changes in CCEP amplitude by high- and low-frequency neurostimulation reflect region-specific effects and may have utility for rapid parameter optimization. These findings highlight a potential strategy to accelerate personalization of neurostimulation therapy for epilepsy.
