Ece Boran1, Georgia Ramantani2, Niklaus Krayenbühl1, Maxine Schreiber1, Kristina König3, Tommaso Fedele4, Johannes Sarnthein5. 1. Klinik für Neurochirurgie, UniversitätsSpital und Universität Zürich, Switzerland. 2. Neuropädiatrie, Universitäts-Kinderspital Zürich, Switzerland. 3. Schweizerisches Epilepsie-Zentrum, Zürich, Switzerland. 4. National Research University Higher School of Economics, Moscow, Russian Federation. 5. Klinik für Neurochirurgie, UniversitätsSpital und Universität Zürich, Switzerland; Zentrum für Neurowissenschaften Zürich, ETH Zürich, Switzerland. Electronic address: johannes.sarnthein@usz.ch.
Abstract
OBJECTIVES: Residual fast ripples (FR) in the intraoperative ECoG are highly specific predictors of postsurgical seizure recurrence. However, a FR is generated by a small patch of cortical tissue. Spatial sampling with standard electrodes may thus miss clinically relevant information. METHODS: We analyzed FR rates in the intraoperative ECoG of 22 patients that underwent resective epilepsy surgery. We used standard electrodes with 10 mm inter-contact spacing (standard ECoG) in 14 surgeries and high-density grid electrodes with 5 mm spacing (hd-ECoG) in 8 surgeries. We detected FR using a previously validated automatic detector. RESULTS: Postoperative seizure freedom was achieved in 14/22 (64%) cases. Across all 42 ECoG recordings, FR rates were higher for hd-ECoG than for standard ECoG. In the 14 seizure free patients (ILAE 1), no residual FR were detected (specificity = 100%). In the 8 patients with seizure recurrence (ILAE > 1), residual FR were detected in 1/7 standard ECoG and 1/1 hd-ECoG (Accuracy ACCstandard ECoG = 57%, CI [29% 82%], ACChd-ECoG = 100%, CI [63% 100%]). CONCLUSION: Denser spatial sampling by hd-ECoG improved FR detection compared to standard ECoG. SIGNIFICANCE: Hd-ECoG may advance seizure freedom after epilepsy surgery.
OBJECTIVES: Residual fast ripples (FR) in the intraoperative ECoG are highly specific predictors of postsurgical seizure recurrence. However, a FR is generated by a small patch of cortical tissue. Spatial sampling with standard electrodes may thus miss clinically relevant information. METHODS: We analyzed FR rates in the intraoperative ECoG of 22 patients that underwent resective epilepsy surgery. We used standard electrodes with 10 mm inter-contact spacing (standard ECoG) in 14 surgeries and high-density grid electrodes with 5 mm spacing (hd-ECoG) in 8 surgeries. We detected FR using a previously validated automatic detector. RESULTS: Postoperative seizure freedom was achieved in 14/22 (64%) cases. Across all 42 ECoG recordings, FR rates were higher for hd-ECoG than for standard ECoG. In the 14 seizure free patients (ILAE 1), no residual FR were detected (specificity = 100%). In the 8 patients with seizure recurrence (ILAE > 1), residual FR were detected in 1/7 standard ECoG and 1/1 hd-ECoG (Accuracy ACCstandard ECoG = 57%, CI [29% 82%], ACChd-ECoG = 100%, CI [63% 100%]). CONCLUSION: Denser spatial sampling by hd-ECoG improved FR detection compared to standard ECoG. SIGNIFICANCE: Hd-ECoG may advance seizure freedom after epilepsy surgery.
Authors: Dorottya Cserpan; Ece Boran; Santo Pietro Lo Biundo; Richard Rosch; Johannes Sarnthein; Georgia Ramantani Journal: Brain Commun Date: 2021-03-23