About a third of migraine patients get 'aura', a range of neurological symptoms that occurs early in the migraine attack. Typically aura lasts for about an hour, but it can go on for much longer. You can also be diagnosed with Migraine Aura without Headache, which is when you get the aura symptoms, but not the headache part of a migraine attack.
It’s not well understood what exactly causes an aura. It’s believed to be caused by a wave of electrical activity, called cortical spreading depression, that spreads across the cortex of the brain. This wave is then followed by a prolonged suppression of nerve cell activity. This can lead to various changes, such as changes in blood flow, which may lead to migraine attack.
Migraine aura can cause a variety of different symptoms.
Visual auras are the most common type of aura. Some symptoms you may experience during a visual aura include:
- seeing jagged flashes of light, stars, or bright spots
- having zigzagging lines or geometric shapes in your field of vision
- partial vision loss or blind spots, also called visual field defects
If you lose the ability to perceive depth, so things look really big or really small, or closer or further away than they are, that is a particular type of visual aura called 'Alice in Wonderland Syndrome'
Other sensory aura symptoms
While vision is the most common sense affected by aura, it can affect any of your senses. You may experience sudden changes or distortion of your hearing, taste or smell, including hearing, tasting or smelling things that aren't there.
Aura can also cause changes in physical sensation or touch. The main symptoms of a sensory aura are feelings of numbness or tingling, or “pins and needles”. It usually begins at the extremities, that is your fingers or toes, and works its way up the limb. This feeling can also occur on one side of your face, lips, or tongue. Alternatively, you might be able to feel nothing at all.
If the tingling feeling is accompanied by motor weakness that is usually diagnosed as hemiplegic migraine.
You may also experience a loss or distortion in your ability to detect temperature, whether that be your brain registering cold as hot or vice versa, or just everything seeming a bit lukewarm.
Speech and language symptoms
Disturbances in speech and language are less common aura symptoms. Symptoms may include:
- slurred speech
- not being able to form the right words