Abstracts

ESES is the EEG pattern of a dramatic sleep activation of continuous spike-wave discharges to [gt] 85%, with or without clinical seizures. Epileptic syndromes with the EEG pattern of ESES include continuous spike and waves during slow wave sleep (CSWS) and Landau[ndash]Kleffner (LKS). An overnight EEG is considered the gold standard for diagnosing ESES. The study aim is to determine whether ESES can be diagnosed by calculating the spike-wave index (SI) during the first 300 seconds (SI-300) of sleep, rather than calculating the entire overnight SI., Overnight (in-patient) EEGs of children (n=7) with ESES were reviewed. For each, the SI-300 was calculated by visual review of the first 300 seconds of non-REM sleep, starting 60 seconds after background slowing and loss of the anterior-posterior gradient and muscle artifact. SI was calculated as a percentage of one-second bins containing at least one (rhythmic) generalized spike-wave complex. The SI-300 was compared with the overnight SI of three 100-second portions of evenly distributed available sleep (1-4 hours apart)., (1) SI-300 accurately predicted the diagnosis of ESES in 100% (7/7) of children. (2) The average discrepancy between SI-300 and overnight SI was 2% (s.d. = 1.4%)., SI-300 correctly predicts ESES in all children of this selected group. This suggests that a conventional awake and asleep EEG, rather than an overnight recording, may suffice in diagnosing ESES. These results suggest that the entity ESES is evident in early sleep as well as in slow wave sleep.,