Changes in current-source density of interictal spikes in benign epilepsy of childhood with centrotemporal spikes following treatment with oxcarbazepine

PURPOSE The aim of this study was to detect clinical variables associated with the extent of change of the irritative zone in benign epilepsy of childhood with centrotemporal spikes (BECTS) after oxcarbazepine monotherapy. METHOD BECTS patients receiving oxcarbazepine monotherapy were retrospectively reviewed. Changes in current-source density (CSD) of the maximum negative points of interictal spikes prior to the start of oxcarbazepine treatment were compared with CSD following oxcarbazepine treatment for 6-12 months. CSD was measured using low-resolution brain electromagnetic tomography (LORETA). Patients were divided into two groups based on the change in CSD: increased-extent or decreased-extent. Comparisons were made between the groups based on the age of onset, seizure frequency before treatment, time interval between seizure onset and treatment start, time interval between the two EEGs, oxcarbazepine dosage at the follow-up electroencephalography, occurrence of daytime seizures, and seizure control. RESULTS Fourteen patients were enrolled. Seven patients were in the decreased-extent group and six in the increased-extent group; one patient was excluded because she did not demonstrate any change in CSD. We found that seizure control differed significantly between the two groups: seizures were well-controlled in six out of seven patients in the decreased-extent group (85.7%), but in only one of six patients (16.7%) in the increased-extent group (p=0.03). The other variables did not differ between the groups. CONCLUSION Seizure control may be associated with the extent of changes in the neuronal irritative zones of BECTS patients. We suggest that changes of CSD extent may be used as an imaging modality to evaluate clinical improvement in BECTS patients.