Abstracts

Rationale: To examine inctal onset, early propagation (EP) and the relationship between them based on Stereo-electroencephalography (SEEG) recordings in the patients with temporal lobe epilepsy (TLE), and to evaluate their predictive validity for the surgical outcome. Methods: Forty-three patients were included in this retrospective study. Five to sixteen multilead electrodes were implanted per patient. After enough seizures recorded, patients underwent a removal of the SEEG electrodes, and approximately 8-12weeks later, they underwent a standard craniotomy for tailored resection of the hypothetical epileptogenic zone (EZ). Post-operative seizure status was evaluated according to Engel’s classification. Results: Four seizure-onset patterns (IOPs) were identified across the 43 seizures: low-voltage fast activity (LVFA: 28%), low frequency high-amplitude periodic spikes (LFPS: 26%), spike or polyspike fast discharges (SpFD: 35%) and spike- or sharp-and-wave rhythmic activity (SpRA: 12%). Ten patients with LFPS (91%; Ia: 55%) and 13 with SpFD (80%; Ia: 73%) were in class I, whereas only 5 with LVFA (50%; Ia: 42%), and 1 SpRA (20%; Ia: 20%) in class I. The patients with LFPS and SpFD had more class I (p=0.003) but not class Ia (p=0.053) compared with those with LVFA and SpRA. Eighteen patients without EP (78%; Ia: 57%) and 11 patients with EP (55%, Ia: 50%) were in class I. Comparing the intratemporal propagation, the early extratemporal propagation within 3s (class I: p=0.005; class Ia: p=0.023) rather than 5s (class I: p=0.028; class Ia: p=0.107) suggested a worse outcome. Five conditions related to ictal onset and EP were combined to predict the surgical outcome in the patients with TLE; the sensitivity and specificity of class I prediction were 83% and 86%. Conclusions: Ictal onset and EP can be applied in surgical outcome prediction in the stage of SEEG recording, and contribute to draw up an optimal surgical plan. Funding: This work supported by China Postdoctoral Science Foundation (2015M571069), Beijing Postdoctoral research Foundation (2015-ZZ-61), Beijing Municipal Science &Technology Commission (Z161100002616016) and National Natural Science Foundation of China (81671285) and National Natural Science Foundation of China (81671285).