The typical migraine headache is unilateral (affecting one half of the head) and pulsating, lasting from 4 to 72 hours; symptoms include nausea, vomiting, photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound). Approximately one-third of people who suffer from migraine headaches perceive an aura —unusual visual, olfactory, or other sensory experiences that are a sign that the migraine will soon occur. __