French guidelines on stereoelectroencephalography (SEEG)

Stereotactic thermocoagulation for insular epilepsy: Lessons from successes and failures

“…The epileptogenic zone (EZ) was considered well localized if low‐voltage fast activity was observed at seizure onset. In addition, postictal depression of activity and reproduction of seizures after low‐ or high‐frequency electrical stimulation contributed to the determination of the EZ localization . FCD pattern (interictal rhythmic activity, burst of rapid rhythms before the ictal discharge, early rhythmic spikes in the postictal phase) had the value of EZ when present.…”

“…In addition, postictal depression of activity and reproduction of seizures after low-or high-frequency electrical stimulation contributed to the determination of the EZ localization. 12 FCD pattern (interictal rhythmic activity, burst of rapid rhythms before the ictal discharge, early rhythmic spikes in the postictal phase 26 ) had the value of EZ when present. EZ was considered not well localized if all these criteria were not present, despite a probable insular seizure onset.…”

“…Increasing interest in insular epilepsy has emerged during the past decade from studies based on stereo-electroencephalography (SEEG) methodology. [1][2][3][4][5][6][7] SEEG techniques for implanting the insula safely have been developed, [8][9][10][11][12][13] and there is growing evidence that SEEG is particularly effective in demonstrating insular seizure onset. [14][15][16] However, the insula lies deep in the sylvian fissure, covered by eloquent frontal, temporal, and parietal opercula with a dense network of vessels.…”

Outcomes of stereoelectroencephalography exploration at an epilepsy surgery center

“…6,17,23 Of the resections, 49% were temporal, 29% were extratemporal, and 22% were multilobar; the latter being higher compared to previous studies. 6 The most common pathologies were HS and FCD as shown in previous studies [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] with 58% showing normal pathology or non-specific changes. Non-specific changes were reported to be either related to chronic epilepsy or secondary to depth electrode implantation.…”

“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] French data have shown average duration of recording to be 8.5 days with 10-13 electrodes implanted per center. 22 Nonconsensual agreement from the same group suggests that when less than 6 electrodes are planned, its relevance should be questioned. Likewise, when more than 15 electrodes are considered, efforts must be made with other investigations to narrow down the implantation hypothesis.…”