Summary:Purpose: Very fast activity was investigated on the ictal EEGs of epileptic spasms to elucidate the pathophysiology of West syndrome (WS) and related disorders from a novel point of view.Methods: The traces of scalp ictal EEG of spasms temporally were expanded in 11 patients whose clinical diagnosis was symptomatic WS in six, cryptogenic WS in two, Aicardi syndrome in one, and symptomatic generalized epilepsy after WS in the remaining two. Time evolution of averaged power spectra of the ictal fast activity also was analyzed in each patient.Results: Rhythmic gamma activity with frequency ranging from 50 to 100 Hz was detected in a total of 345 of 537 spasms.Fast activity was seen bilaterally in nine patients, was lateralized to one hemisphere in another, and appeared independently on each hemisphere in the remaining infant with Aicardi syndrome. Power spectra showed a clear peak corresponding to spasmassociated gamma rhythm, with frequency centering ∼65 Hz and ranging from 51 to 98 Hz. The morphology and spectral characteristics of ictal gamma rhythm were completely different from those of muscle activity or alternating current (AC) artifacts.Conclusions: Spasm-associated gamma activity was clearly detected on the scalp. This observation may provide a clue to the pathophysiology of spasms.

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SUMMARYBecause high-frequency oscillations (HFOs) may affect normal brain functions, we examined them using electroencephalography (EEG) in epilepsy with continuous spikewaves during slow-wave sleep (CSWS), a condition that can cause neuropsychological regression. In 10 children between 6 and 9 years of age with epilepsy with CSWS or related disorders, we investigated HFOs in scalp EEG spikes during slow-wave sleep through temporal expansion of the EEG traces with a low-cut frequency filter at 70 Hz as well as through time-frequency power spectral analysis. HFOs (ripples) concurrent with spikes were detected in the temporally expanded traces, and the frequency of the high-frequency peak with the greatest power in each patient's spectra ranged from 97.7 to 140.6 Hz. This is the first report on the detection of HFOs from scalp EEG recordings in epileptic patients. We speculate that epileptic HFOs may interfere with higher brain functions in epilepsy with CSWS.

The observed FOs corresponded to epileptogenicity because of their close relation to the severity of hypsarrhythmia during the course of ACTH treatment. The very high epileptic FO rates in hypsarrhythmia are thought to affect the process of neurodevelopment by interfering with physiological functions in West syndrome, taking into account that high frequencies are also important in physiological higher brain functions.

Summary: Purpose:To discuss and propose a definition of autonomic status epilepticus (SE), describe its clinical and EEG features, and review what is known about its epidemiology, pathophysiology, differential diagnosis, and management.Methods: An international consortium of established researchers in the field was identified from their published work, agreed the purpose of the project, searched the literature, and, by use of e-mail communication, agreed the consensus document.Results: Autonomic SE is a condition lasting at least 30 min and characterized by epileptic activity causing altered autonomic function of any type at seizure onset or in which manifestations consistent with altered autonomic function are prominent (quantitatively dominant or clinically important) even if not present at seizure onset. It is best described, and probably most commonly encountered in children, with Panayiotopoulos syndrome. However, it also occurs in children with symptomatic epilepsies and, exceptionally, in adults. Its pathogenesis and most appropriate management are poorly understood Conclusions: It is hoped that this document will help clinical recognition of Autonomic SE, reduce misdiagnosis, and promote further interest and studies into what has been a relatively neglected area.