There are four possible phases to a migraine attack. They are listed below - not all the phases are necessarily experienced. Additionally, the phases experienced and the symptoms experienced during them can vary from one migraine attack to another in the same person:
- The prodrome, which occurs hours or days before the headache.
- The aura, which immediately precedes the headache.
- The pain phase, also known as headache phase.
- The postdrome.
ProdromeProdromal symptoms occur in 40–60% of those with migraines. This phase may consist of altered mood, irritability, depression or euphoria, fatigue, yawning, excessive sleepiness, craving for certain food (e.g. chocolate), stiff muscles (especially in the neck), hot ears, constipation or diarrhea, increased urination, and other visceral symptoms. These symptoms usually precede the headache phase of the migraine attack by several hours or days, and experience teaches the patient or observant family how to detect that a migraine attack is near.
AuraFor the 20–30% of migraine sufferers who experience migraine with aura, this aura comprises focal neurological phenomena that precede or accompany the attack. They appear gradually over 5 to 20 minutes and generally last fewer than 60 minutes. The headache phase of the migraine attack usually begins within 60 minutes of the end of the aura phase, but it is sometimes delayed up to several hours, and it can be missing entirely (see silent migraine). The pain may also begin before the aura has completely subsided. Symptoms of migraine aura can be sensory or motor in nature.
Visual aura is the most common of the neurological events and can occur without any headache. There is a disturbance of vision consisting often of unformed flashes of white and/or black or rarely of multicolored lights (photopsia) or formations of dazzling zigzag lines (scintillating scotoma; often arranged like the battlements of a castle, hence the alternative terms "fortification spectra" or "teichopsia").
Some patients complain of blurred or shimmering or cloudy vision, as though they were looking through thick or smoked glass, or, in some cases, tunnel vision and hemianopsia. For those suffering from this the prodrome is a small blurred spot that we cannot focus on. This is followed by a growing into a larger object such as a three sided square with the zig-zag line interfering with vision. This grows to a maximum size and then starts moving slowly through the field of vision until it exits the field of view. For all practical purposes the aura phase has then ended even if brain activity could be detected that would indicate an active aura.
The somatosensory aura of migraine may consist of digitolingual or cheiro-oral paresthesias, a feeling of pins-and-needles experienced in the hand and arm as well as in the nose-mouth area on the same side. The paresthesia may migrate up the arm and then extend to involve the face, lips and tongue.
Other symptoms of the aura phase can include auditory, gustatory or olfactory hallucinations, temporary dysphasia, vertigo, tingling or numbness of the face and extremities, and hypersensitivity to touch.
Oliver Sacks's book Migraine describes "migrainous deliria" as a result of such intense migraine aura that it is indistinguishable from "free-wheeling states of hallucinosis, illusion, or dreaming."