A migraine aura is a specific type of prodrome, or premonition, that heralds a migraine. It is a symptom or series of symptoms that let migraineurs, people who suffer from chronic migraines, know in advance that a migraine headache is about to make itself felt.
Aura effects develop over about five minutes and generally occur from twenty minutes to an hour prior to the start of a headache. They are a symptom of what used to be called “classic migraine”. Recently, medical practitioners have moved to a more scientifically accurate term, migraine-with-aura. Only about 15-20% of migraineurs consistently experience any kind of aura before a headache begins.
Most migraine auras are visual. These auras are called positive visual phenomena because, rather than their vision fading or going dark, people who experience them see things. Examples include:
-Auras or Haloes: a nimbus of light or haze surrounding objects, particularly light sources
-Flashing or Floating Lights: colored or white (rarely dark) spots that appear to move
-Lightning Bolts: a jagged or zigzag line that sparkles and/or arcs over the field of vision; with the frequency or severity increasing over time until the person can no longer see (a whiteout); This effect usually stops with the onset of headache pain.
-Photophobia: an extreme sensitivity to light; this effect frequently lasts the duration of the headache
Most auras last less than an hour. Migraineurs who experience auras that last more than an hour are said to suffer from migraines with prolonged aura. In some cases a migraineur may experience aura effects without a headache developing, but it is still considered to be a symptom of chronic migraines. At various times the same person may experience all three variations, migraine with aura, migraine with prolonged aura, or typical aura without headache.