Impaired visual inhibition in migraine with aura

Objective: The pathophysiology of migraine with or without aura (MA, MO) is still a matter of debate. We thus studied patients with MA and MO by means of paired-pulse flash-visual evoked potentials (paired F-VEPs). This technique, recently revived, analyses the overall excitability of visual system as detected from the cortical occipital signal. Methods: We enrolled 13 adult patients with MO and 13 with MA. Twenty-two normal subjects of similar age and sex acted as controls. Stimuli were single flashes, intermingled at random to flash pairs at critical interstimulus intervals (ISIs, 16.5-125 ms) with closed and open eyes. The "single''(unconditioned) F-VEP was split into a "main complex'' (50-200 ms after the flash) and a "late response'' (200-400 ms). As for paired stimulation, the "test'' F-VEP emerged from electronic subtraction of the "single'' F-VEP to the "paired'' F-VEP. Its size was expressed as "test''/"single'' F-VEP*100. Results: As for paired F-VEPs, the "main complex'' of the "test'' F-VEP in the MA group did not show the size reduction (at ISIs 50-62.5 ms) which was typical among the control and MO groups (p <= 0.016) in the "eyes-closed'' state. Conclusions: Paired F-VEPs document a defective neural inhibition in the visual system of patients with MA. Significance: Paired F-VEPs may warrant inclusion in future preclinical/clinical studies, to evaluate its potential role in the pathophysiology and management of MA. (C) 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.