Abstracts

Rationale: Despite childhood absence epilepsy (CAE) being the most common pediatric epilepsy syndrome and availability of many antiepileptic drugs (AEDs), only ethosuximide (ESM) and valproic acid (VPA) have been shown to be most efficacious and tolerable in initial empirical treatment1,2. Often misperceived as a benign form of epilepsy, CAE is associated with variable remission rates and affected children have cognitive deficits and long term psychosocial difficulties3,4,. The choice between ESM and VPA should be made with careful consideration. The aim of this study was to understand the role of serial electroencephalogram (EEG) recordings in defining the potential to become seizure free shortly after starting the AED therapy in a clinical setting. Methods: This was a retrospective analysis of 44 consecutive AED naïve patients with CAE undergoing treatment between 2008 and 2016 at a community based epilepsy center. Serial 1- hour video EEG (vEEG) recordings were obtained at baseline, and at 2 months and 6 months study periods after starting ESM or VPA to compare drug efficacy by determining seizure freedom and normalization of EEG. A total of 5 patients (ESM group-4, VPA group-1) were late for the 3rd EEG and therfore were not included in the 6 month study period observations. Chi-square and p value at < 0.5 were calculated to determine statistical significance. Results: After the baseline vEEG, per parents' choice, 28 patients were started on ESM and 16 on VPA. At 2-month study period, of the 28 patients treated with ESM, 22 (78.6 %) continued to have spike and wave (S/W) discharges on EEG, and 17 (60.7%) were seizure free. In the VPA group of 16 patients, 11 (68.8 %) had persistent spike and wave discharges, and 13 (81.2%) were seizure free (p value of 0.16 not significant at p < 0.05). In patients who continued to have seizures in the ESM group, 8 patients were changed to VPA and 1 chose to add VPA. In the VPA group with continued seizures, ESM was added for 2 patients. At 6 months, out of 17 patients who continued ESM, in 2 out of the 3 patients with seizures, no control was obtained. Out of 22 patients who were on VPA (as monotherapy or polytherapy with ESM), 6 had no seizure control. Conclusions: 1) The VPA group shows a trend towards better clinical seizure control and EEG normalization than the ESM group at 2-month study period. 2) At 6-month study period, patients who failed ESM and were switched to VPA, had improved seizure control, while in those who failed VPA, addition of ESM did not change the outcome. 3) A larger study trying to delineate correlation between EEG pattern at baseline and response to ESM and VPA at early stage of AED treatment is warranted.  This study was approved by Kaiser-SC-IRB. Funding: None.