Epilepsia partialis continua: Correlation of semiology, outcome and electrophysiologic features

Epilepsia partialis continua (EPC) is a special form of cortical epilepsy. Several studies have described the ictal and interictal electroencephalography (EEG) findings in patients with EPC; however, lateralizing and localizing values of these findings have been evaluated rarely. This study investigated the correlation of semiologic and EEG findings, and outcomes in patients with EPC.

Clinical and EEG findings and outcomes, and their correlations were studied prospectively in 15 patients who were diagnosed as having EPC upon presentation to Istanbul Medical Faculty Hospital between January 2010 and April 2014, and retrospectively in 5 previously evaluated patients.

EEG findings were lateralizing in 11 (47.8%) of the overall 23 EEG recordings, 7 (30.4%) of which were also localizing. Eleven (55%) of the 20 patients had poor prognosis. Patients with interictal lateralizing EEG findings had better outcomes compared with patients who had interictal non-lateralizing EEG findings (P = 0.016). Periodic epileptiform discharges (PEDs) were noted in the 6 EEGs (3 ictal EEGs and 3 interictal EEGs) of 5 patients, all of whom had poor outcomes (P = 0.04). All four patients with false lateralizing EEG findings had poor outcomes.

EEG has low lateralizing and localizing value in EPC but patients with interictal lateralizing EEG findings have better outcomes, which may be used as a prognostic tool in EPC. The presence of PEDs and false lateralizing findings in EEG might be associated with poor prognosis in EPC.