Why Light Worsens Migraine Headaches

Look3r2010: Jan. 12, 2010 -- Researchers in Boston say they’ve gained new insight into why light makes migraine headaches so painful.

The culprit, they say, is a new pathway that underlies sensitivity to light during migraine episodes in blind people and people with normal eyesight. Scientists at Beth Deaconess Medical Center report their findings in the online journal Nature Neuroscience.

Migraines, which afflict more than 30 million people in the United States, are painful headaches for which sufferers often seek relief by going into dark rooms. Migraines are believed to develop when the system of membranes surrounding the brain and central nervous system, called the meninges, becomes irritated.

That stimulates pain receptors and triggers a series of events that lead to prolonged activation of groups of sensory neurons, the scientists report.

“This explains the throbbing headache and accompanying scalp and neck-muscle tenderness experienced by many migraine patients,” says Rami Burstein, PhD, professor of anesthesia and critical care at Beth Israel and Harvard Medical School.

Migraines cause one-sided, throbbing pain, and have been called “sick headaches” because they have long been associated with vomiting, nausea, irritability, and fatigue.

People with migraines also are also typically aggravated by light with worsening of symptoms compared to being in the dark. This causes many migraine sufferers to wear sunglasses, often at night, Burstein says.

It was the observation that even blind people who suffer migraines were experiencing sensitivity to light, referred to as photophobia, that led Burstein and Rodrigo Noseda, PhD, to hypothesize that signals transmitted from the retina to the optic nerve were triggering the intense headaches, the authors say.

The scientists studied two groups of blind people with migraines. Patients in one group were totally blind because of eye diseases, unable to see images or sense light.

People in a second group were legally blind, but were able to detect the presence of light.

“While the patients in the first group did not experience any worsening of their headaches from light exposure, the patients in the second group clearly described intensified pain when they were exposed to light, in particular blue or gray wavelengths,” Burstein says in a news release. “This suggested to us that the mechanisms of photophobia must involve the optic nerve, because in totally blind individuals, the optic nerve does not carry light signals to the brain.”

He says they suspected that a group of recently discovered retinal cells that help control biological functions, including sleep and wakefulness, were critically involved in this process, because “these are the only functioning light receptors left among patients who are legally blind,” Burstein says.

In laboratory experiments involving animals, they traced the path of specific cells through the optic nerve to the brain. A group of neurons then became electrically active.

“When small electrodes were inserted into these ‘migraine neurons’, we discovered that light was triggering a flow of electrical signals that was converging on these very cells,” Burstein says. “This increased their activity within seconds.”

When the light was taken away, the neurons remained activated, which explains “why patients say that their headache intensifies within seconds after exposure to light, and improves 20 to 30 minutes after being in the dark,” Burstein says.

The discovery of the new pathway will provide scientists a new path to follow in trying to solve photophobia, he says.

The study, the authors write, reveals “a mechanism for the exacerbation of migraine headache by light.”

“Clinically, this research sets the stage for identifying ways to block the pathway so that migraine patients can endure light without pain,” Burstein says.

http://www.webmd.com/migraines-headaches/news/*******2/why-light-worsens-migraine-headaches

PTBO52: I use to suffer terrible migraines but over past 5 yrs. only when the barometer really drops suddenly. If I wake up with one, it is stronger and lasts longer. I know most of the triggers so read labels carefully esp. looking for MSG in products.

Look3r2010: Thx 4 the info.

baldrik: I suffer from Fibromyalgia which includes Migraines, I do get over-sensitive to light as well as sound but sometimes (apparently) migraines don't actually have to be painful, just uncomfortable. I was told this by a Doctor and found it hard to believe until the Fibro but having had this I can say it does seem to be true. It's not easy to explain but you still "cringe" at loud noise or squint at bright light even though it doesn't hurt. The tense neck muscles may in fact be the cause of the migraine and not a result of it, I know in my case this appears to be the case as when the tension starts occasionally it can be relived by massage which eases the migraine.

Qz: I also suffer from migranes since my youth. At one point I had a neurologist tell me drink heavily [no joke]. I was already drinking alot and occasionally using drugs. But I took his advice and drank more. If I could get drunk at least 3-4 days a week I did not get migranes, I did have wicked hangovers. After I quit drinking and drugging the migranes returned. Now I watch carefully what I eat and take notice of patterns. The digestive process plays a role some people claim.
I also wear sunglasses alot. Even inside the house. These things require alot of research on our own. Then trial and error. I hope the best for all who endure these terrible pains.

Kiraharder: i have a rare brain disease whiuch cuses me to have terrable mirgrasine pain which has lead me to stay in my room 24/7 the pain is soo much im on tyleonlu 3 anf thisd other pain med to help my brain i cant takr this anymore if anyone has and info on mirgrines plz help im tired of living like a prsioner in my own home its not fun ive done a cat scan and i am going thoguh more test which is lame i have to stay in bed due to the pain my brain has cuse me to feel i havent eatn well i only started eaten recently it happen to me that i eat then i stop i look like a skelton im really skinny and im writing this is anyone has info pls adddd me message me with help ful hints bout mirgraines i do live in the dark and put cold ice packs on my neck to help but wAT ELSE can i do pls help !!!!!!!!!!!!!! my rare brain disease is no joke !!!!!!!!!! oh and i have eplieplsy too so double the fun which can cuse mirgraine if u have a sezurie after wards lame

spacecake: This is why shades are useful, it's not because I'm a vampire or anything.

flatlander17: I have tried to figure out what triggers my migraine headaches and thought maybe it was set off by an allergy to dust. The light theory sounds good but I'm in the light everyday but only have migraines once or twice a year. I'm glad someone is trying to figure it out because they really are debilitating. :-)

spacecake: Light causes intense auras, that can be both beautiful and haunting.