Abstracts

Myoclonic Astatic Epilepsy (MAE) is a generalized epilepsy syndrome with multiple seizures types including myoclonic (MS), astatic (AS), atypical absence (AAS), tonic-clonic (GTCS) and rarely, tonic seizures, occurring in previously normal children. Outcome and response to treatment are variable. We investigated the clinical and electroencephalographic (EEG) features of MAE to identify factors that relate to favorable outcomes.
We reviewed charts of 8 patients who met the criteria for MAE.
Follow up was 13-76 months (mean=33.4) in 7 patients and 4 months in 1. Seven of 8 were boys. All had normal neurological examinations, MRI scans, and metabolic work up at diagnosis. Development was normal in all prior to seizure onset. Mean age of onset was 30.2 months (19-46 months). Predominant seizures were MS (3 patients), AS (3) and MS/AS (2). One patient experienced non-convulsive status epilepticus (NCSE). There was a family history of epilepsy in 4 and of febrile convulsion in 3. Six patients were seizure-free for 6-47 months (mean=22.6). All patients were treated with multiple AED. Among the responders, 1 was on ketogenic diet (KD), 1 was on felbamate (FBM), 1 was on topiramate (TPM), 1 was on valproate (VPA), and 2 were on lamotrigine (LMT) at remission. Two patients not in remission had partial responses to VPA and TPM. VPA was ineffective in 3, phenobarbital (PB) in 2, TPM in 2, clonazepam in 1, [amp] oxcarbazepine (OXC) in 1. LMT, FBM, and KD were effective for all patients treated with them. Among responders, seizures stopped at 33-75 months of age (mean=51.3[italic])[/italic]. Time from diagnosis to remission ranged from 2-33 months (mean=19.3). All EEGs showed generalized atypical spike and wave discharges. Of five patients with multiple EEGs, 4 showed evolution of epileptiform activity corresponding to clinical seizure activity. At last visit, 6 patients had normal development. Two had mild developmental delay (DD); 1 girl with DD with partial response to VPA, had NCSE, sleep related GTCS, and multifocal MS. A boy with DD was a responder but had the longest duration from diagnosis to remission (33 months). The child with 4 months follow-up, while not in remission, maintained normal development.
Males predominated in our patients with MAE. Genetic factors may play a role in the genesis of MAE as a significant family history of epilepsy and febrile convulsion was noted. Overall seizure and developmental outcome in our retrospective series was excellent with seizure remission of 75% and DD in only two (25%). Epileptiform activity on EEG correlated with clinical seizure activity and can be used as a parameters for guiding treatment. Adverse prognostic factors for developmental outcome were long duration until seizure remission and difficulty with seizure control. LMT, FBM, and KD were effective treatment for MAE while PB and OXC were not. VPA and TPM showed mixed results.