Ictus emeticus induced by photic stimulation.

It has been recently established that ictus emeticus originates from mesial temporal lobe structures. We herein report a patient with generalized epilepsy who exhibited ictus emeticus reflexly triggered by intermittent photic stimulation accompanied by generalized photoparoxysmal responses on the electroencephalogram. All seizures and EEG abnormalities ceased after treatment with valproic acid. The occurrence of ictus emeticus in generalized epilepsy is an apparent paradox, better explained by the theory of "secondary temporalization" implying the selective engagement of temporal lobe structures during generalized seizures.