Cortical excitability changes in chronic migraine vs episodic migraine: evidence by sound-induced flash illusions

Introduction: Sound-induced flash illusions(SIFI) permit to evaluate crossmodal audio-visual perception. When one flash is accompanied by two beeps, it is perceived as two flashes(’fission’illusion); a ‘fusion’ illusion occurs when a single beep causes the fusion of a double flash stimulus. SIFI strictly depends on cortical excitability: healthy controls perceive less illusions by increasing visual cortex excitability through anodal tDCS [1]. Aim: to evaluate if, due to cortical hyperexcitability, differences in SIFI occur in migraine and further changes can be found across migraine cycle, migraine chronification an drug overuse. Methods: we enrolled 64 patients with episodic migraine, 32 w…