Epileptic spasms in clusters without hypsarrhythmia

Abstract

Here we present an update of the electroclinical features and evolution of patients with epileptic spasms (ES) in clusters without hypsarrhythmia, with or without focal or generalized paroxysmal discharges on the interictal electroencephalography (EEG). Between February 1990 and July 2012, 26 patients met the electroclinical diagnostic criteria of ES in clusters without hypsarrhythmia. The etiology of the ES was unknown in 15 patients and structural in 11. Age at onset of the ES was between 2 and 32 mo, with a mean age of 9 mo. Fifteen patients had seizures before the onset of ES. Focal spikes were observed in 12 patients, bilateral spikes and spikes and waves in nine, multifocal spikes in three, and two patients had a normal EEG. The ictal EEG recording showed diffuse high-amplitude slow waves in 15 patients, diffuse slow waves followed by voltage attenuation in six patients, and diffuse fast rhythms in five. ES resolved in six patients after a mean follow-up of 9 yr. Neuropsychological development has been normal in these six patients. Twenty patients continue with seizures refractory to antiepileptic drugs after a mean follow-up of 13 yr. Two of them were operated; they are seizure free, with a normal neuropsychological development. Of the 18 remaining patients, 10 have severe mental retardation, five have moderate mental retardation, and three have mild mental retardation. All but 14 of them show behavioral disturbances. Our patients represent an epileptic encephalopathy that may be considered a distinct epileptic syndrome rather than a variant of West syndrome.

Keywords

Childhood - clusters - encephalopathy - epileptic spasms - infantile spasms - hypsarrhythmia