Purpose:Our aim is to examine ictal onset patterns (IOPs), extratemporal early propagations (EPs) and inner relationship between them based on stereo-electroencephalography recordings in the patients with atypical temporal lobe epilepsy, and to evaluate their impact on seizure prognosis and cognitive outcomes after epilepsy surgery. Methods:Forty-three patients were included in this retrospective study. Five to sixteen multilead electrodes were implanted per patient. All of them underwent a standard craniotomy for tailored resection of the hypothetical epileptogenic zone. Post-operative seizure status and cognitive outcomes were evaluated by Engle's classification, Wechsler intelligence and Wechsler memory scale. Results:Four types of IOPs were identified in the 43 patients. The patients with low frequency highamplitude periodic spikes (LFPS) and spike or poly-spike fast discharges (SpFD) had better seizure outcomes. There were ten patients with extratemporal EPs, who had worse clinical outcomes than those without extratemporal EPs (Engel's class I: χ2 =10.689, p=0.001; Engel's class Ia: χ2 =4.251, p=0.039). Three conditions related to IOPs and extratemporal EPs were combined to predict the seizure prognosis after operation. The sensitivity and specificity were 90.0% and 78.6% for Engel's class I, and were 87.0% and 55.0% for Engel's class Ia. The patients with LFPS showed more significant improvement in memory quotient (MQ) but not in full intelligence quotient (FIQ) than those with other IOPs. Conclusions:IOPs and extratemporal EPs are closely related to seizure status and cognitive outcomes after epilepsy surgery in atypical TLE patients.