Abstracts

Rationale: We investigated the relationship between locations of broadband peri-ictal electrocorticographic activities determined by the semi-automatic maximum detection method and seizure outcomes in 23 medically intractable epilepsy patientsMethods: Included were 23 patients with medically intractable epilepsy who underwent chronic electrocorticography. Seizure outcomes were followed more than 1 year. Investigated peri-ictal periods were -30 s to 15 s from the ictal onset. Prominent electrocorticographic activities were extracted in the wavelet transformed domain in 28 scales from 600Hz to 0.07Hz separately. Activities were detected by amplitude and duration thresholdings. Subsequently, we selected one electrode having the maximum wavecluster amplitude in each seizure. Thereafter we compared the mean resection percentage of maximum electrodes between seizure outcome groups between the seizure-free and the not-seizure-free groups by Mann-Whitney U tests. Benjamini-Hochberg false discovery rate corrections were done for 28 scales. Significances were judged at the adjusted p-value of 0.05 level. Thresholds were automatically optimized with the genetic algorithm to distinguish seizure outcome groups with the lowest p-value.Results: 15 patients were seizure free at one year follow-up. Resection extents of maximum amplitude waveclusters were significantly different between seizure outcome groups in 3 scales including 41Hz, 29Hz, 0.36Hz within 10s from the ictal onset after Benjamini-Hochberg multiple comparison corrections (corrected p-values 0.037, 0.028 and 0.028). Before multiple comparison correction, resection extents were significantly different between seizure outcome groups in 5 scales including 15 Hz, 2.7 Hz, 2 Hz, 0.25 Hz and 0.18 Hz within 20s from the ictal onset (corrected p-values 0.078, 0.105, 0.105, 0.077 and 0.093).Conclusions: The significant relationship between resection extents of zones with intra-slow, gamma and delta activities and seizure outcomes was found in the peri-ictal electrocorticography. Better delineation of resection targets may be possible in future by broadband electrocorticography.