Complete seizure freedom is possible in patients with MTLE-HS after surgery in spite of extratemporal electro-clinical features

Summary Purpose The aim was to identify the common typical and atypical ictal semiologic and EEG features of patients with mesial temporal lobe epilepsy and hippocampal sclerosis who became seizure-free postoperatively. Method The semiologic and EEG findings of 126 ictal video-EEG recordings of 50 patients who remained seizure-free for at least 2 years (mean = 9.46 ± 3.20; range = 3–14.5 years) after surgery were reviewed. Statistical analysis was used to determine the frequencies of the most common auras, semiologic features and EEG patterns and to define the symptom clusters. Results Aura was reported in 82% ( n :41) of patients and the most common type was epigastric sensation. Early symptoms were contralateral upper extremity dystonic posturing (66%), oro-alimentary automatisms (50%) and ipsilateral hand automatisms (40%). Ictal EEG findings revealed localized and lateralized activity in 62% of patients. Of the 17 most common early symptoms, there was a tendency toward two clusters. Cluster 2 consisted of findings that were typical for patients with mesial temporal lobe epilepsy whereas Cluster 1 mostly consisted of atypical findings. Conclusions This study demonstrated two clusters of the semiologic repertoire, and the most frequent EEG finding was lateralized and localized ictal activity, while other types of EEG patterns were also recorded. Although the presence of atypical findings may suggest a more extended or even extratemporal zone, the seizure-free outcome demonstrated that if the critical amount of tissue can be resected within the epileptogenic network, this may be sufficient for termination of seizures.