Characteristics of migraine visual aura in Southern Brazil and Northern USA

Background: Migraine aura, made up of one or more neurological symptoms arising from the cortex or brainstem, is a complex neurological phenomenon. Visual aura is the most frequent aura manifestation. Studying the subjective components of visual aura makes it possible to identify common characteristics. Objective: To thoroughly describe the characteristics of migraine visual aura in patients with migraine with aura. Methods: We performed a retrospective, descriptive study of the visual aura of 122 migraine patients collected at two headache clinics in the Americas. This study was designed to determine the characteristics of a typical visual aura. Results: The most common features of the visual aura in our study are that it occurs before the headache with a gap of less than 30 minutes, lasts 5 to 30 minutes, has a gradual onset, usually begins peripherally, is unilateral, and shimmers. Furthermore, the location of typical visual aura in the visual field has no fixed relationship to headache laterality, is slightly more often without color, and is often described as small bright dots and zigzag lines. Blurred vision, not typically considered to be an aura phenomenon of cortical origin, is in fact the most frequently reported visual symptom. Conclusions: Migraine visual aura is heterogeneous and pleomorphic, and some of our findings run contrary to common beliefs.