Dear Doctor: I never have headaches, but I have visual disturbances that I believe are migraine auras. They're not bothersome and clear up within 10 minutes. But are they dangerous in any way? Am I having a migraine?
Dear Reader: When we venture into the area of migraine, we're entering the unknown. It's one of the leading disorders in the world, and yet when it comes to understanding how or even why migraines occur, we are just beginning to find answers.
The word "migraine" calls up the idea of a monster headache, but the disorder is in fact a collection of symptoms. Sufferers can experience nausea, dizziness, depression, exhaustion, sensory hallucinations, severe neck pain and, as you know firsthand, visual disturbances.
Until recently, migraine was thought to have vascular origins. That is, researchers believed it was the result of the constriction and expansion of blood vessels within and around the brain. With the advent of highly sensitive imaging technologies, however, and thanks to volunteers who have allowed the course of their migraine attacks to be visualized in real time, the focus has now shifted to the brain itself.
At UCLA, we're extremely fortunate to have the Headache Research and Treatment Program, headed by Andrew Charles, M.D., a neurologist and a leading migraine specialist. It's through his research that we now know that fluctuations in brain chemicals, as well as abnormal electrical activity in certain regions of the brain, play a significant role in migraine attacks. This includes not only the extreme headache pain associated with migraine, but the other symptoms as well. In fact, the throbbing, pulsating nature of a migraine headache, once considered to reflect the sufferer's heartbeat, is now believed to sync up with brain waves.
All of which brings us to your question. Visual disturbances that are not accompanied by a headache are known as an ocular migraine. These disturbances can include a circle of flickering zigzag lines that suddenly appear and then slowly expand outward until they leave your field of vision. Some people experience temporary blind spots in their vision, see shimmering patterns or stars, or get random flashes of light.
Scans of migraine patients' brains show waves of abnormal activity that spread across the surface of the brain. There is also stimulation of nerve centers deep within the brain stem. Thanks to the new focus on the brain itself as the source of migraine, researchers are now looking into how ocular migraines tie into altered brain activity.
When it comes to ocular migraine, the symptoms can be temporarily disruptive but are not generally considered serious. In light of the scope of nonheadache symptoms that migraine encompasses, it's a good idea to do a self-check and see whether fatigue, depression, light sensitivity or neck pain either precede or follow your ocular migraine attacks.
Since you're experiencing these symptoms regularly, we suggest a visit with your primary care physician for a definitive diagnosis. Pay attention during the next episode, so you can provide accurate details and a precise timeline of the attack. It will help your physician better understand what is going on and potentially rule out conditions with similar symptoms.
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