Abstracts

Rationale: Epilepsy with myoclonic atonic seizures (EMAS) is a rare childhood developmental and epileptic encephalopathy. Three centers through the pediatric epilepsy research consortium previously did a retrospective review of 166 children with EMAS to identify factors associated with favorable developmental and seizure outcomes. This data is now extended to five centers to include 215 patients. This is the largest EMAS cohort to date

Methods: Retrospective chart review of patients identified with EMAS per ILAE guidelines.

Results: 215 patients were included. 96% children were developmentally normal at onset; presenting seizure type was generalized tonic clonic in 55%, drop (myoclonic or atonic) in 35%; absence in 10% with mean age at seizure onset at >24 months in 83%. First treatment used was levetiracetam (67%); valproic acid (10%) or any other combined ASM in 25%. Nutrition therapy (ketogenic diet) was used as a first/second/ third treatment in only 44/215 patients (20.4%). Overall responses to first-, second- or third-line therapy was 23%, 22%,18% respectively. Nutrition therapy was eventually used in 144 patients with response in 99 (68.75%) versus the overall response to either first/ second/ third therapy of 56.2% (121/ 215 patients; p=0.017 ). Ultimately seizure freedom was attained in 54% and 47% had global developmental delay ( >1 domain). Factors associated with seizure freedom on univariate analysis at p < 0.05 included normal genetic work up and use of nutrition therapy while factors associated with continued seizures were subsequent EEG slowing and seizures recorded on EEG. Factors associated with final global developmental delay included lack of seizure freedom, subsequent EEG slowing, developmental delays prior to seizure onset, developmental regression during course and epileptiform activity on first EEG. On multivariate analysis factors associated with final seizure freedom was global developmental delay (p < 0.001), while factors associated with final developmental outcome included seizure freedom (p < 0.001); abnormality on genetic workup (p=0.04) lack of subsequent slowing on EEG (p=0.03) and lack of developmental regression during course (p < 0.001).