Does Early Recognition of Treatment Failure and Changing Anti-Epilepsy Medication Regimen Improve Short-Term Seizure Remission Rates In Childhood Absence Epilepsy?

Purpose: To study the role of early serial EEGs in improving seizure freedom rates after initiation of ethosuximide or valproic acid for childhood absence epilepsy.

Methods: Retrospective data analysis study of AED naive patients with childhood absence epilepsy undergoing treatment at the community-based epilepsy clinic. Due to small sample size Fisher's exact test was used to determine two-tailed p value at less than 0.05 statistical significance..

Results: At 2-month study period 71.4% patients in the ethosuximide and 87.5% in the valproic acid group achieved seizure freedom, with EEG normalization in 21.4% and 50% respectively. At 6-month study period, in patients continuing ethosuximide, seizure freedom and EEG normalization rates were 89.5% and 52.6% respectively; while in patients continuing valproic acid, results were 100% and 78.6% respectively. Both at 2-month and 6-month study periods, a trend towards higher seizure freedom was noted in patients with typical versus non-typical epileptiform discharges at baseline with the valproic acid group showing a superior response.

Conclusion: Although no statistically significant difference in response rates was noted, 1) a shift towards higher seizure freedom with valproic acid; 2) improved response after switching to valproic acid at 2 months, if warranted; and 3) superior response rate in patients with typical EEG epileptiform discharges at baseline were observed. A larger study is needed to define the role of early serial EEGs to delineate higher drug failure probability; and to determine the importance of non-typical EEG characteristics at baseline in relation to the choice of AED and long-term outcome Keywords: childhood absence epilepsy, ethosuximide, valproic acid, non-typical epileptiform discharges.