Periodic spasms: an unclassified type of epileptic seizure in childhood.

Seven boys aged between 14 months and 13 years with focal or multifocal partial epilepsy had very unusual seizures, characterized by series of periodic bilateral spasms. These consisted of a brief, complex movement of slight to severe intensity, mainly involving the axial muscles, with raising of the shoulders, adversion of the eyes and head, often with rictus-type facial grimaces and occasional stretching of the legs and emission of a guttural sound. The ictal EEG showed a pattern of periodic complexes, characterized by a slow wave with superimposed fast activity. This form of epileptic seizure is resistant to treatment and is found only in patients affected by a brain disease consisting of a fixed or progressive encephalopathy. These observations document the existence of a rare form of seizure or epileptic event, not yet included in the International Classification of epileptic seizures and clinically relevant because of its diagnostic and prognostic implications.