TY - JOUR
T1 - The optimal montage to mark interictal epileptiform discharges and high-frequency oscillations in intraoperative electrocorticography
AU - Wang, Ziyi
AU - Guo, Jiaojiao
AU - Schaft, Eline
AU - Hoogteijling, Sem
AU - Ferrier, Cyrille H.
AU - Visser, Gerhard H.
AU - Sun, Dongqing
AU - Hoefnagels, Friso
AU - Inada, Taku
AU - van der Salm, Sandra
AU - Huiskamp, Geertjan
AU - van Klink, Nicole
AU - van't Klooster, Maryse
AU - Zijlmans, Maeike
N1 - Publisher Copyright:
© 2025 The Authors
PY - 2025/1
Y1 - 2025/1
N2 - Objective: In intraoperative electrocorticography (ioECoG), interictal epileptiform discharges (IEDs) and high-frequency oscillations (HFOs; ripples 80–250 Hz, fast ripples (FRs) 250–500 Hz) can be identified in average or bipolar montage. We studied how montage choice affects event identification. Methods: Two reviewers independently marked IEDs and HFOs across three montages (average, horizontal- and vertical-bipolar) from 13 patients who were seizure-free after ioECoG-guided surgery. We analyzed the number of channels-with-events, total events count, events morphology (maximum-amplitude, duration, frequency), number of instances with overlapping events across multiple channels (event_instance), concordance of event_instances over montages, and percentage of channels-with-events in the resected-area. Results: Bipolar montages yielded more channels-with-events, higher counts, and greater maximum-amplitude of IEDs and ripples compared to average montages. Average and horizontal-bipolar montages yielded more IED_instances than vertical-bipolar montages. Average montages detected the highest percentage of event_instances occurring only in this montage. Event duration, frequency, and percentage of channels-with-events in the resected-area did not differ across montages. Conclusions: All three ioECoG montages are clinically useful to find epileptic events. The bipolar montage detects more events with greater amplitude, while the average montage uncovers a wider variety of unique events. Combining montages provides complementary information. Significance: This study quantitatively revealed how different montages capture epileptiform events.
AB - Objective: In intraoperative electrocorticography (ioECoG), interictal epileptiform discharges (IEDs) and high-frequency oscillations (HFOs; ripples 80–250 Hz, fast ripples (FRs) 250–500 Hz) can be identified in average or bipolar montage. We studied how montage choice affects event identification. Methods: Two reviewers independently marked IEDs and HFOs across three montages (average, horizontal- and vertical-bipolar) from 13 patients who were seizure-free after ioECoG-guided surgery. We analyzed the number of channels-with-events, total events count, events morphology (maximum-amplitude, duration, frequency), number of instances with overlapping events across multiple channels (event_instance), concordance of event_instances over montages, and percentage of channels-with-events in the resected-area. Results: Bipolar montages yielded more channels-with-events, higher counts, and greater maximum-amplitude of IEDs and ripples compared to average montages. Average and horizontal-bipolar montages yielded more IED_instances than vertical-bipolar montages. Average montages detected the highest percentage of event_instances occurring only in this montage. Event duration, frequency, and percentage of channels-with-events in the resected-area did not differ across montages. Conclusions: All three ioECoG montages are clinically useful to find epileptic events. The bipolar montage detects more events with greater amplitude, while the average montage uncovers a wider variety of unique events. Combining montages provides complementary information. Significance: This study quantitatively revealed how different montages capture epileptiform events.
KW - Electrode grid
KW - Epilepsy surgery
KW - High-frequency oscillations
KW - Intraoperative electrocorticography
KW - Montage
UR - https://www.scopus.com/pages/publications/105009751914
U2 - 10.1016/j.cnp.2025.06.007
DO - 10.1016/j.cnp.2025.06.007
M3 - Article
C2 - 40687074
AN - SCOPUS:105009751914
SN - 2467-981X
VL - 10
SP - 246
EP - 255
JO - Clinical Neurophysiology Practice
JF - Clinical Neurophysiology Practice
ER -