Abstracts

Rationale: Epileptic spasm is not an official terminology in ILAE seizure classification, however, it is often observed in the clinical field as an independent semiology in intractable epilepsies. We performed this research to identify common characteristics of surgical candidate for epilepsy surgery in epileptic spasm and to compare the accuracy of each diagnostic modalities in preoperative evaluation by comparing with intracranical EEG (IC-EEG). Methods: We reviewed medical records of epileptic spasm patients who took the surgical treatment in Cincinnati children’s hospital. Electrophysiolocial data and neuroimaging data were reviewed on epilepsy surgical conference board meeting. Totally, eight patients were recruited (M:F=5:3). Mean age at operation was 5.50 years old ( 1.25-17 yr), mean age of onset was 1.34 years old ( 0-5 yr), and mean duration from onset was 4.16 years (0.92-12.8 yr). On past medical history, one patient had experienced prolonged labor, one had survived from HSV encephalitis, and one had insulted from hemorrhagic infarct during chemotherapy to ALL. All 8 patients showed developmental delay. Results: Four out of 8 patients showed symmetric spasm, and other 4 patients showed asymmetric spasm which were clearly concordant with intal IC-EEG and brain MRI in terms of lateralization. Three patients had accompanying seizure during episode (CPS followed by spasm: 1/3, Aura followed by spasm: 2/3). By interictal EEG, only one patient showed definite lateralization, and four patients showed probable lateralization (a. spike + diffuse bursts or b. bilateral but unilaterally dominant spike), three patients failed to lateralize, and none could achieve correct localization. By ictal EC-EEG, all 8 patients were successful in definite or probable lateralization, on the other hand, three out of 8 patients could achieve probable localization. All of 8 patients were lesional cases by MRI. Lateralization and localization values of other imaging studies were as follows: SISCOM (lateralization: 6/7, localization: 3/7), PET (lateralization: 8/8, localization: 3/8), MEG (lateralization: 4/6, localization: 2/6), and high frequency analysis (lateralization: 3/3, localizaton: 2/3). Five patients have been maintaining surgical outcome as Engel class I, but two patients as class II (Case 1: 1.25 years old, heterotopia + diffuse delta on ictal EC-EEG, Case 5: 5yrs, left T lobectomy + P cortisectomy with saving of Wernicke area) and one patient as class III (Case 8: 1.16 years old, left hemimegalencephaly + left hemispheric attenuation on ictal EC-EEG + omission of IC-EEG). Conclusions: Epileptic spasm with lesional MRI finding can be nicely eligible for epilepsy surgery. Ictal EC-EEG, brain MRI, and HFA seem to be more powerful for lateralization, however, there is no dominant diagnostic tool for localization. More cautious evaluations are required for a younger patient, and a patient whose suspicious focus is close to the eloquent area.