Speed of progression of migrainous visual aura measured by sequential field assessment

Abstract

Homonymous hemianopia can occur due to migraine, a clinical syndrome of unknown etiology. Cortical spreading depression (CSD) has been suggested to underlie migraine visual aura. Functional magnetic resonance imaging (fMRI) studies gives an estimate of the speed of the spread of this electrophysiological event (3.5 ± 1.1mm/min). Our observation of a changing hemianopic visual field loss was documented using a Humphrey visual field analyzer. Using this data and matching it with the retinotopic map of primary human visual cortex, an average speed of 3.65 mm/min was calculated. This finding reinforces previous studies that hypothesize CSD to be responsible for changes in visual function associated with migraine.