For most people, it's hard to imagine anything good about a migraine headache. The pain is so crushing, so excruciating, that most sufferers would give almost anything to be rid of it.
Unable to communicate their suffering to their families, their friends or their doctors, some migraine sufferers have turned to paint and paper to express the depth of their misery.
A collection of 80 vivid paintings done by migraine sufferers currently on display in San Francisco sheds light on the sometimes strange and usually distressing experience of migraine.
Roughly 10 percent of the population in the United States suffers from migraine, yet it is a little-understood affliction that many people prefer to hide rather than acknowledge.
Medical science has yet to find what causes, or cures, it. Yet specialists who study it find migraine to be one of the most fascinating -- and frustrating -- areas of medicine.
Dr. Oliver Sacks, neurologist and author of best-selling books portrayed in the recent Hollywood film "Awakenings," says "It's part of the human condition. There have been descriptions of migraine for 2,000 years."
Sacks doesn't minimize the serious pain that migraine brings, but he finds fascination with the "aura," or visual disturbances -- zigzag patterns that move across the field of vision, flashing lights, undulating images -- that precede the headache in some people.
"The headache is not too inspiring," Sacks says. "The nausea is not pleasant."
But with the aura, he says, "Migraine provides a sort of stimulation and excitation of the visual parts of the brain, so they shoot off all sorts of strange phenomena. They can be distressing to the patient."