The idiopathic form of West syndrome.

The clinical and electroencephalographic data of 31 children with cryptogenic West syndrome (WS), selected from a series of 103 WS patients, with a follow-up between 4 and 12 years, were studied retrospectively to verify whether this group included patients who fulfilled the criteria for an idiopathic etiology. The results identified a possible idiopathic etiology in 17 patients (55%), who had a family history of other forms of idiopathic epilepsy or febrile convulsions, or who developed, during the follow-up, an EEG genetic trait such as a photoconvulsive response or spike-and-wave discharges, or rolandic spikes. All 17 children had a favorable outcome and all had normal neuropsychological development. Four children (13%) fulfilled the criteria for a true cryptogenic etiology, a causative lesion being suspected, but never proved. At the end of the follow-up all four had seizures, or developmental delay or both, all signs that suggest an underlying cerebral lesion. The other 10 children, representing 32% of the cryptogenic cases, had a good prognosis, with early disappearance of spasms and hypsarrhythmia, and normal neurological development, but none had an EEG epileptic trait or family history of epilepsy or febrile convulsions; although they could have had an idiopathic WS, this was not proved. We conclude that among the children classified as having a cryptogenic WS, many--in our series at least 55%--fulfill the criteria for an idiopathic etiology.