Abstracts

Rationale: Continuous spike wave syndrome (CSWS) is simultaneous presentation of almost continuous spike-wave activity on EEG during slow wave sleep and neuropsychological deficits including: Global developmental delay and regression, delay/regression of a specific cognitive function e.g. language, motor impairment: ataxia, dyspraxia, dystonia, unilateral deficit Electrical status epilepticus in sleep (ESES) is an EEG pattern observed in some childhood epileptic encephalopathies with: generalized/localized sleep potentiated spikes in >50% of slow wave sleep, preservation of REM sleep, reduction or absence of CSWS during REM. However, no clear treatment guidelines exist. Several authors targeted EEG pattern with antiepileptic medications including (Valproic acid, Ethosuximide, High dose diazepam (DZM), clobazam, levetiracetam, corticosteroids, IVIG) assuming, neuropsychological regression, CSWS, and frequent interictal epileptiform discharges are related. Methods: 3000 video-EEG-monitoring-patients, admitted to Upstate Medical University between 2009 and 2013, were reviewed for sleep potentiated spikes, clinical presentation, natural history, and treatment responses. Spike-wave index (SWI) was calculated as the number of spikes in 100 15-second pages in the initial non-REM slow wave sleep cycle. Patients with a SWI of 1000 were included in the study. Patients were offered a single oral 1-1.5 mg/kg diazepam dose at bed time (HS), and a second SWI was obtained within 24 hours to determine immediate treatment response. The same dose was repeated on the following night of admission followed by quantification of the SWI the next day. Results: 46 patients (1.53%) presented a spike-wave index (SWI) 1000. Spikes were left posterior temporal (P7) in 54.35%, left mid temporal (T7) 52.17%, right mid temporal (T8) 43.48%, or left central (C3) 41.30%. Mean age of patients with ESES was 8.12 years and median age was 8 years. Seizures were complex partial in 44%, and generalized tonic clonic in 30%. Comorbidities included developmental delay in 26%, language and learning disability in 15% of patients. Periventricular leukomalacia/encephalomalacia due to perinatal hypoxic ischemic injury was the predominant MRI finding. Fourty five patients received 1-1.5 mg/kg of diazepam (DZM) orally, QHS. Majority of patients had levetiracetam (71.74%), and valproic acid (23.91%) as their maintenance anticonvulsant medications. Mean pretreatment SWI was 1536.26 spikes per 100 15-second pages, which declined to 597.09 following initial DZM treatment, and to 320.43 following the second treatment with high dose DZM. This translated to a mean SWI reduction of 61.65% after first DZM treatment, 48.70% reduction from first to second DZM treatment leading to a total SWI reduction of 79.68% (p < 0.01).Conclusions: Diazepam is an effective adjuvant with favorable acute and mid-term results, despite rare intolerance due to sedation. Further studies to determine the long-term and neuropsychological outcome after diazepam treatment are necessary to better delineate the long-term value of this anticonvulsant in CSWS treatment.