Why is migraine rarely, and not usually, the sole ictal epileptic manifestation ?

Purpose and methods: Migraine, with or without aura, affects from 10% to 14% of the population, and is as such one of the most common headache disorders. A unified hypothesis for the physiopathology of migraine and its relationship with epileptic migraine and migralepsy has yet to be formulated. Trigemino-vascular system (TVS) activation is believed to play a crucial role in the ‘‘pain phase’’ in migraine; cortical spreading depression (CSD) is considered to be the primary cause of TVS activation. On the basis of data in the literature, I would like to stress that TVS activation may originate at different cortical and subcortical levels. For example, as recently reported, an epileptic focus, originating and propagating along cortical non-eloquent/silent areas, through CSD, rarely causes TVS activation with migraine as the sole ictal epileptic manifestation. Results and conclusion: The multiple considerations that arise from this hypothesis, including the underdiagnosed ictal epileptic headache, are discussed; EEG (ictal and inter-ictal) recording with intermittent photic stimulation (IPS), according to the standardized international protocol, is strongly recommended in selected migraine populations.