An attack may consist of defined phases:

1. A warning or prodromal phase may occur – there may be sensations or signs that a migraine is about to happen. Changes in mood and appetite may occur, as well as nausea, fatigue, yawning, difficulty finding words, diarrhoea or constipation.
2. About 20-30% of people may experience an aura. The most common aura symptoms are visual disturbances such as bright zigzag lines, blind spots that may move or gradually expand, flashing lights.  Aura affects vision in both eyes (though it may seem to affect one only) and can last from 5 to 60 minutes.  Less commonly, an aura can affect sensation in the face or limbs, or speech. 
3. A headache phase.
4. A resolution phase as the headache gradually fades.