Migraines Go Green

by Guy McKhann, M.D.

July 21, 2017

This is a column from Dana's print publication, Brain in the News.

Migraine is a very common form of headache, occurring in about 15 percent of people, and more commonly in adult women. I doubt that there are any readers of this column who do not know someone who suffers from migraines.

Besides the headache, a common manifestation of migraine is sensitivity to sensory stimuli, particularly bright lights and loud noises. Thus one has the prototypical impression of a migraineur (a person with migraine) lying in bed in a dark, quiet room with a cool, damp cloth over his or her forehead.

In those with migraine, the effect of light is not only exacerbation of the headache, but also induction of behavioral symptoms such as nervousness, irritability, and depression. These symptoms can be induced both during a migraine attack or when the person is free of headache. In contrast, those without a history of migraine have none of these responses to light.

The sensitivity of migraineurs to bright light has been known for many years, but studies of how that sensitivity might work have been lacking until a few years ago. A group led by Rami Burstein and Rodrigo Noseda at Beth Israel Deaconess Medical Center in Boston tried something new: They subjected their migraineurs to different colors of light. The responses were the same with all colors tested except green. With green light there was much less response, and in some instances the headaches even got better.

The group at Beth Israel has made some other interesting observations about light and migraine. They turned to blind people who have migraine. They divided the blind people into two categories: those whose blindness was related to problems in the retina and those whose blindness was caused by more central problems, such as optic nerve damage. In the retina group, exposure to bright lights caused headache and behavioral problems, just as in non-blind migraineurs. The other group had no response to bright lights. Their explanation is that there are nerve cells in the retina that respond to light but send their signals to the brain by pathways different from the usual visual processing pathways.

This is clinical research at its best. The Boston researchers have taken a commonly accepted phenomenon, the sensitivity of migraineurs to bright lights, and have shown that the color of that light makes a difference. A selective color band of green does not elicit an adverse response, and may actually be protective. Further, for a practical clinical application, they have tried to use that information to aid migraineurs by developing light bulbs with only green light, and also glasses that would filter out all colors except green. Both these efforts are in progress.

The other sensitivity for migraineurs is sound, hence the retreat to a quiet room during an attack of headache. To my knowledge, no group has researched the components of sounds as they relate to headaches. Maybe that is next on the Boston group’s list.