An aura is a set of temporary neurological symptoms, most commonly visual disturbances like flashing lights or zigzag lines, that signal a migraine is about to start. About 25% of people who get migraines experience auras, and they typically last between 5 and 60 minutes before fading completely. While the term “aura” has other meanings in spiritual and metaphysical contexts, the medical version is what most people encounter when searching for answers to strange visual or sensory episodes.
What an Aura Looks and Feels Like
Visual symptoms are by far the most common type of aura. They usually begin as a small disturbance in your field of vision, then expand outward over several minutes. What you might see includes blind spots (sometimes outlined by a circle or other simple shape), zigzag lines that float slowly across your vision, shimmering spots or stars, flashes of light, or a temporary partial loss of vision. These visual changes typically affect both eyes.
Not all auras are visual. Some people feel tingling that starts in one hand or on one side of the face, then slowly creeps along the arm or leg before turning into numbness. Tingling can also affect the tongue or mouth. Less commonly, an aura causes difficulty finding words or speaking clearly, ringing in the ears, hearing loss, or muscle weakness on one side of the body. When weakness is involved, it’s classified as a hemiplegic migraine.
A useful way to think about aura symptoms is that they come in two flavors: “positive” symptoms, where your brain generates something extra (bright lights, tingling, ringing sounds), and “negative” symptoms, where function drops away (blind spots, numbness, inability to move). It’s common to experience a positive symptom first, followed by a negative one. For instance, you might see bright zigzag lines that gradually give way to a temporary blind spot. This pattern of positive-then-negative symptoms is actually one of the features that helps distinguish a migraine aura from something more serious like a stroke.
What Causes It in the Brain
Auras are caused by a phenomenon called cortical spreading depression: a slow wave of electrical activity that rolls across the surface of the brain at a rate of about 2 to 5 millimeters per second. As this wave passes through a region, neurons fire intensely, then go quiet. The wave temporarily disrupts the normal balance of charged particles inside and outside brain cells, causing potassium to flood out and calcium to drop. Water shifts into nerve cells, making them swell briefly.
This is why aura symptoms build gradually rather than hitting all at once. When the wave crosses the visual processing area at the back of your brain, you get visual disturbances. When it reaches areas responsible for sensation, you feel tingling or numbness. The slow spread of the wave explains why symptoms often march across your body, starting in the hand and creeping up the arm, or beginning as a small visual flicker and expanding across your field of vision. The whole process is fully reversible. Neurons recover within minutes, and no lasting damage occurs in the vast majority of cases.
How Long It Lasts and When It Happens
Most auras last between 5 and 60 minutes, with the typical episode falling in the 30 to 60 minute range. Aura symptoms usually appear before the headache pain begins, though they can also overlap with it. If you experience more than one type of aura symptom during a single episode (say, visual changes followed by tingling), they tend to occur in sequence rather than all at once, which extends the total duration. Three symptoms in a row could mean up to three hours of aura, though that’s uncommon.
Some people experience aura without any headache following it at all. This is sometimes called a “silent migraine,” and it can be particularly confusing if you don’t have a history of migraines. It’s more common in people over 50 who had migraines with aura earlier in life.
Aura in Epilepsy
Migraine isn’t the only condition that produces auras. In epilepsy, an aura is actually a small seizure itself, specifically the earliest stage of a focal seizure where you remain fully aware of what’s happening. Epileptic auras last from a few seconds to a couple of minutes and feel different depending on where in the brain the seizure originates.
Seizures starting in the inner part of the temporal lobe often produce a rising feeling in the stomach, déjà vu, a sudden sense of fear, or unpleasant smells. Seizures from the outer temporal lobe can cause vertigo, buzzing or ringing sounds, or visual disturbances. Occipital lobe seizures produce visual auras similar to migraine, while parietal lobe seizures may trigger visual hallucinations, panic, or a sensation in the stomach. The key difference from migraine aura is timing: epileptic auras tend to be much shorter (seconds rather than minutes) and may be followed by impaired consciousness rather than headache.
Aura and Stroke Risk
People who experience migraine with aura have roughly double the risk of ischemic stroke compared to people without migraines. A large meta-analysis found a pooled relative risk of 2.2 for ischemic stroke in people with aura, while migraine without aura showed no meaningful increase over baseline. This elevated risk appears to be independent of traditional cardiovascular risk factors like high blood pressure or cholesterol, suggesting the connection between migraine aura and stroke operates through a separate mechanism.
The absolute risk remains small for most people, but it becomes more relevant in combination with other factors. Women who experience aura and also use estrogen-containing birth control or smoke are in a higher-risk category. This is why many doctors recommend against combined hormonal contraceptives for women who have migraines with aura.
Staying Safe During an Episode
Because aura can distort your vision, create blind spots, cause dizziness, or impair your ability to speak and think clearly, driving during an episode is a genuine safety concern. Visual disturbances and cognitive fog can both interfere with your ability to operate a vehicle safely. If you feel an aura coming on while driving, pulling over is the safest choice. Many migraine treatments can also cause drowsiness, dizziness, or weakness that further impair driving ability.
If your auras are predictable enough that you recognize the early signs, that recognition becomes a practical advantage. It gives you a window to stop what you’re doing, move to a safe and comfortable environment, and take any treatment you use before the headache phase begins. People who get auras at work or while traveling often develop personal protocols: keeping medication accessible, identifying a quiet spot to wait it out, or having a plan for getting home without driving.