Cortical folding influences migraine aura symptoms in CADASIL

Objective Migraine with aura is a hallmark of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). In contrast with the majority of CADASIL patients, some affected subjects never experience visual symptoms during their attacks of migraine with aura. The aim of this study was to determine whether specific morphology of the primary visual cortex is associated with the absence of visual symptoms during migraine aura in CADASIL. Methods Patients from a large cohort of CADASIL patients, aged <45 years, and with a modified Rankin's scale <= 1 were included in the study. Width and depth of the calcarine sulcus in the primary visual cortex as well as cortical thickness in its neighbourhood were compared between patients with visual and those with non-visual migraine auras. Results 31 patients had visual symptoms (VA group) while nine reported only non-visual symptoms (NVA group) during their migraine auras. Asymmetry index of the calcarine sulcal depth largely differed between the NVA group and the VA group (0.22 +/- 0.1 vs -0.004 +/- 0.2; p=1.7 x 10(-6)). The width of the right calcarine sulcus was significantly lower in the VA group (p=0.04) and cortical thickness was larger in the NVA group (p=0.03). Conclusion The absence of visual symptoms during migraine auras was associated with a profound asymmetry of the primary visual cortex. Aura symptoms seem to be linked to the morphology of the primary visual cortex in CADASIL. This finding potentially reflects more general relationships between spreading depression and cortex morphology in migraine with aura.