Abstracts

Rationale: Electrical status epilepticus in sleep (ESES) is an EEG pattern observed in some childhood epileptic encephalopathies with generalized spike-waves occupying ≥ 80-85% of slow-wave-sleep. Similar patients with regional sleep-potentiated spikes have not been well studied. The objective of this study is to assess and compare the clinical presentation, natural history, and acute treatment outcomes in ESES and focal sleep-potentiated spikes (FSPS). Methods: 3000 video-EEG-monitoring-patients, admitted to Children’s Hospital Boston between 2001-2009, were reviewed for sleep potentiated spikes, clinical presentation, natural history, and treatment responses. Spike-wave index (SWI) was calculated as percentage of one-second bins containing at least one spike in the first 5 minutes of each hour of non-REM sleep. Patients with a SWI of ≥ 80% were included in the study. Patients were offered a single oral 1mg/kg diazepam dose at bed-time (HS), and a second SWI was obtained within 24 hours to determine immediate treatment response. Results: 51 patients (1.7%) presented a spike-wave index (SWI) ≥ 80%. Spikes were generalized in 14 (ESES) or regional in 37 (FSPS) patients. Mean age of patients with ESES was 8.43 years versus 6.32 years in FSPS. Whereas seizures were observed more often in ESES, a tendency towards more frequent language delay/regression, abnormal motor exam, behavioral problems, more frequent family history of neurological conditions, history of complicated labor and delivery were seen in the FSPS group. MRI abnormalities were more frequent in the FSPS group, periventricular leukomalacia/encephalomalacia being the major finding (Table 1). 32 FSPS and 9 ESES patients received 1mg/kg of diazepam orally. In ESES patients, mean pretreatment SWI of 79.8% acutely declined to 48.8% (p < 0.01). A pretreatment SWI of 78.6 was acutely reduced to 36% in FSPS patients (p < 0.01). Conclusions: ESES and FSPS are associated with different clinical features that may represent poles of a continuous spectrum of epileptic encephalopathies with sleep-potentiated spikes. Clinical presentation includes seizures, language delay/regression, developmental delay, and behavioral problems. High dose diazepam acutely reduces the SWI. Further studies to determine the long-term and neuropsychological outcome after diazepam treatment are under way. Careful comparison of the anatomical substrates and clinical manifestation of the two forms of sleep-potentiated EEG abnormalities are warranted.