Some features of migraine with aura clearly set it apart from migraines without aura. Aura is present in 15% to 20% of migraine sufferers. Most often it consists a visual disturbance, which consists of either gradual loss of vision, starting from the periphery of visual field and moving to the midline. Many people see shimmering and sparkling lights with or without loss of vision and some see things smaller than they are. Sensory aura consists of pins-and-needles, tingling and numbness on one side of the body, often starting with the hand, moving up the arm and then involving the face. Typical aura lasts 20-60 minutes, but it can be shorter or longer. Auras are usually followed by a headache, but sometimes it occurs without any pain. People who have auras are at a slightly higher risk of having a stroke. This risk is magnified by other factors, such as smoking, high-dose estrogen contraceptives, hypertension, diabetes, and high cholesterol.
A recent study by Austrian neurologists published in Headache examined 54 patients who kept a detailed diary and recorded a total of 354 migraine auras. Using a statistical tool called multivariate analysis they discovered that smoking, menstruation, and hunger were likely to increase the risk of having an aura. Holidays and days off reduced the possibility of experiencing an aura. They also found that non-migraine headaches and migraine without aura were more likely to occur during menstruation, psychological stress, tiredness, odors, and were decreased by smoking.
The surprising finding in this study is that the risk f having a migraine with aura was doubled in the first three days of menstruation. The consensus of headache specialists has been that menstrual migraine is typically a migraine without aura, although at least one other study by Danish doctors also reported menstruation as a trigger of migraine with aura.