Electrographic patterns at seizure onset as prognostic factors for epilepsy surgery

Description: Background: Predicting the epilepsy surgery outcome is indispensable and difficult. The objective of this work is to stablish if the EEG pattern of seizure onset recorder with intracranial electrodes can be used as a prognosis factor of the surgical outcome. Methods: Seizure ictal onset patterns wre analysed retrospectively in 153 seizures of 31 patients who underwent intracranial EEG recording (iEEG) prior to surgery. Onset frecuency was classified by visual analysis into convetional EEG frecuency bands. Onset extensions was divided into focal (fewer than four contacts) and lobar (more than five contacts). Ictal seizure onset waveform was distributed into numerous types based on their ictal morphology. Ictal onset patterns were divided into the first three changes. These features were correlated with the surgical outcome classification was used for the correlation; grades I and II were considered favourable outcome. The two-tailed Fisher's exact test was used in order to correlate the surgical outcome with the different seizure ictal onset patterns. Interpretation: Diffuse electrodecremental event is not associated with bad surgical outcome. Seizure ictal onset arising from temporal lobe structures is not related to better surgical outcome.

Topic: HISTORY OF EPILEPSY
EPILEPSY SYNDROMES
DRUG RESISTANT
INTRACRANIAL ELECTRODES