Unilateral photoconvulsive response in agenesis of the corpus callosum.

An 11-year-old female presented with the unusual coexistence of self-induced photogenic epilepsy and an atypical epileptiform ictal EEG pattern evoked by intermittent photic stimulation. The EEG showed irregular 2.5-4 Hz spike-wave and polyspike-wave complexes, strictly localized on the left hemisphere, and associated with impairment of consciousness and myoclonic jerking of the contralateral side of the body. A computer tomographic scan showed agenesis of the corpus callosum. According to the literature on corpus callosum section in uncontrolled epilepsies, we hypothesize that in our patient the agenesis of the corpus callosum probably prevented the generalization of the ictal EEG pattern evoked by intermittent photic stimulation.