The pathophysiological mechanisms underlying migraine are more difficult to investigate in children than in the adult population. Abnormal cortical excitability turns out to be one of the most peculiar aspects of migraine, accounting for the manifestations of migraine attacks. Recently, visual cortical excitability has been explored effectively in adult migraineurs with a technique based on cross-modal audio-visual illusions (with sound-induced flash illusions (SIFIs) being reduced in migraineurs compared to non-migraineur subjects). On such a basis, in this study, we investigated visual cortical excitability in children with migraine using SIFIs using combinations of visual and sound stimuli presented randomly. We evaluated 26 children with migraine without aura and 16 healthy children. Migraineurs did not differ from the age-matched healthy subjects regarding fission or fusion illusions but perceived more flashes in trials of multiple flashes with or without beeps. The higher number of SIFIs in migraineur children compared to adults may be due to a greater propensity of visual stimulation to be driven by auditory stimuli (i.e., acoustic dominance). The increased ability to perceive flashes reveals a hyperfunctional visual cortex, demonstrating that the use of SIFIs is a valid tool for assessing visual cortical responsiveness even in pediatric migraine.
