You may experience more than one phase, although not necessarily all of them. The prodrome phase occurs hours to days before the headache.
Some people also experience gastrointestinal symptoms such as nausea, constipation, or diarrhea.
Although symptoms in the prodrome vary widely, each person usually has his or her own specific set of symptoms that signal a migraine. The aura phase immediately precedes or accompanies an attack. Migraines with visual disturbances are called classic migraines. The most common aura is flashing lights in a her- ringbone pattern. Some people see bright lights in other geometric patterns, or half of their visual field is blank.