What are Silent Migraines?

Silent migraines are a medical oddity. How can you have a migraine "headache" without headache pain? The answer lies in the still unfolding mystery of migraine. WebMD explains what silent migraines are as well as their unusual visual symptoms, commonly called aura.

Silent migraine: What is it?

Migraine is a neurological disorder that generally includes headaches. But it doesn’t always. Some people have "silent migraine" -- a migraine without the symptom of headache pain. 

To understand silent migraine, it helps to know the four distinct phases of migraines.

• Prodrome. The "prodrome" phase warns that a migraine is coming. Symptoms include changes in your mental state, such as irritability or confusion, and physical signs such as thirst or diarrhea. One out of every four migraine sufferers experiences prodrome symptoms as early as 24 hours before the migraine pain attacks. 
• Aura. The phenomenon called aura is best known for its unusual visual symptoms. But other sensory, motor, and language disturbances can occur. About one in five migraine sufferers experiences aura. Aura is a phase that typically lasts about an hour. 
• Pain. Migraine pain itself is often on one side of the head. It’s often a throbbing pain and may be accompanied by nausea, vomiting, and extreme sensitivity to light and sound. The pain phase can last from several to 72 hours. 
• Resolution. After a migraine, many people experience deep fatigue and general malaise for up to 24 hours.

Not all migraines follow this pattern. There are migraines with and without aura. There are also migraines with and without pain. Even within the same person, migraines are extremely unpredictable.

Silent migraines: Migraine symptoms

The symptoms of silent migraine include any of the typical signs and symptoms of a migraine -- but without the pain.

Physical symptoms include:

• diarrhea
• nausea
• vomiting
• food cravings
• loss of appetite
• thirst
• increased urination
• chills
• fatigue

Emotional and mental symptoms include:

• confusion
• irritability
• euphoria

Aura symptoms include:

• wavy or jagged lines
• flashing lights
• dots or spots in your vision
• blind spots
• tunnel vision
• disruptions in hearing
• auditory hallucinations
• distortions in smell or taste
• numbness, a pins-and-needles feeling, or other unusual body sensations
• difficulty remembering or saying a word
• other language difficulties

The American Migraine Study in 1999 involved 30,000 people with migraines. Nine out of every 10 said they couldn't work or function normally when they had migraines. More than half said they experienced symptoms severe enough to need bed rest. Even without the pain of migraine, the other symptoms can be temporarily disturbing. They can disrupt your normal day.

Silent migraines: What causes silent migraines?

Researchers are now looking at migraine aura and pain as two distinct mechanisms. Doing so is leading to a better understanding of silent migraine.

In the past, experts thought migraines were primarily a problem with blood flow in the brain. That is they thought of them as "vascular" events. They now believe aura is a "neurovascular" event. That means it involves the way nerve cells are firing in the brain and how nerve cell activity relates to the brain's blood flow. Aura appears to be a case of overstimulation and then depression of nerve cell activity in the brain.