Non-convulsive status epilepticus and audiogenic seizures complicating a patient with asymmetrical epileptic spasms.

A female infant suffered from epilepsy since the neonatal period, which evolved into West syndrome at the age of 2 months. Spasms in series and hypsarrhythmia disappeared after treatment with high-dose phenobarbital; however, single spasms persisted with right-sided predominance, and polyspike activity in the left parieto-temporal areas preceded or coincided with these spasms. Magnetic resonance imaging revealed a small calcification in the right occipital area, and positron emission tomography showed hypometabolism over the right hemisphere. Widespread epileptic discharges gradually increased on electroencephalography (EEG) during sleep thereafter. The patient presented with daytime unresponsiveness at 1 year and 6 months, when diffuse, irregular spike and wave activity characterized the waking EEG. Spasms or brief tonic seizures with right-sided predominance were provoked by auditory stimuli during this period, particularly by her mother's voice, with ictal EEG of right posterior predominant fast activity and subsequent desynchronization. The administration of clobazam resulted in the marked improvement of EEG findings and transient disappearance of spasms. Presumably, certain patients with asymmetrical epileptic spasms may be regarded as a unique type of localization-related epilepsy, and can show an unusual course of evolution in comparison to other cases of epilepsy that evolve after West syndrome.