An aura is a set of temporary neurological symptoms, most often visual, that signal the beginning of a migraine. Auras typically last between 5 and 60 minutes and are completely reversible. About 25 to 30 percent of people with migraines experience them, though the exact symptoms vary widely from person to person. Some people get auras before every migraine, others only occasionally, and a small group experiences auras without any headache at all.
What Happens in Your Brain During an Aura
An aura is caused by a phenomenon called cortical spreading depression: a slow-moving wave of intense electrical activity that rolls across the surface of the brain. During this wave, a large population of brain cells fires all at once, then goes quiet for several minutes. Think of it like a power surge followed by a temporary blackout in a specific brain region. The wave travels at a pace of a few millimeters per minute, which is why aura symptoms tend to build gradually and shift across your field of vision or spread from one body part to another rather than appearing all at once.
The type of symptom you experience depends on which part of the brain the wave passes through. When it moves across the visual cortex at the back of the brain, you get visual disturbances. When it reaches areas responsible for sensation, you feel tingling or numbness. This gradual spread is one of the key features that distinguishes an aura from something more serious like a stroke.
Visual Aura Symptoms
Vision changes are by far the most common type of aura. A systematic review of studies found a wide range of visual symptoms, with some appearing in the majority of patients and others in only a small fraction. The most frequently reported include:
- Zigzag or jagged lines: reported by 24 to 81 percent of people with aura, often shimmering or flickering at the edges
- Flickering light: 12 to 91 percent
- Scotoma (a blind spot): 23 to 77 percent
- Foggy or blurred vision: 25 to 54 percent
- Small bright dots or stars: 19 to 70 percent
- Flashes of bright light: 16 to 38 percent
- Looking through heat waves or water: 8 to 24 percent
The classic “scintillating scotoma” that many people describe is actually a combination of these: a shimmering, zigzag-edged arc surrounding a blind spot, often starting near the center of your vision and expanding outward over 10 to 30 minutes. Less common visual symptoms include tunnel vision, objects appearing larger or smaller than they are, stationary objects seeming to move, and mosaic-like patterns breaking up your visual field. A very small number of people (1 to 3 percent) experience complex visual hallucinations.
Sensory, Speech, and Motor Auras
Not all auras are visual. Sensory auras are the second most common type and often follow visual symptoms by a few minutes. They typically start as tingling or pins-and-needles sensations in one hand or on one side of the face, then slowly spread up the arm or across the cheek. Some people feel it on half of their tongue. After the tingling passes, localized numbness can linger for up to an hour.
Speech and language auras are less common but can be alarming. You might struggle to find the right word in conversation, have difficulty forming sentences, or find that words come out jumbled. Motor auras, which cause temporary weakness on one side of the body or face, are the rarest type and can last longer than other auras, sometimes persisting up to 72 hours.
A key pattern across all aura types is the sequence of “positive” symptoms followed by “negative” ones. Positive symptoms are things your brain generates that aren’t really there: flashing lights, tingling, zigzag lines. Negative symptoms are losses of normal function: blind spots, numbness, difficulty speaking. Seeing the shimmering arc first, then being left with a blank area in your vision, is a textbook example of this positive-to-negative sequence.
Aura Without Headache
Some people experience the full aura sequence but never develop a headache afterward. This is sometimes called a “silent migraine” or acephalgic migraine, and it is well recognized in medical literature. The visual or sensory symptoms are identical to those that precede a typical migraine: a bright arc of zigzag lines expanding over 20 minutes, then fading, with no pain following. Silent migraines can occur at any age but are more common in people over 50 who had migraines with aura earlier in life. For some, the headache phase simply drops away over the years while the aura persists.
Rare Perceptual Distortions
In uncommon cases, auras produce more exotic effects on perception. Alice in Wonderland syndrome is a rare condition most commonly triggered by migraine aura, in which your brain’s ability to process sensory information is disrupted. Objects around you may appear dramatically larger or smaller than they are. Your own body may feel distorted, as if one hand has swollen to several times its normal size. Your sense of time can stretch or compress, and you may feel disconnected from your body or surroundings. These episodes, while disorienting, are temporary and resolve like any other aura.
How Aura Differs From a Stroke
Because auras can involve vision loss, numbness, and difficulty speaking, it’s natural to worry about stroke. The two conditions share some surface-level similarities, but they behave differently in ways that matter.
Aura symptoms tend to build gradually over minutes and spread from one area to another. They produce positive symptoms first (shimmering lights, tingling) before negative ones (blind spots, numbness). Stroke symptoms typically arrive suddenly and are predominantly negative from the start: sudden numbness, sudden vision loss in half the visual field, sudden inability to speak. The gradual march of symptoms is one of the most reliable features distinguishing aura from a stroke.
That said, the distinction is not always perfectly clean. Some strokes begin with positive symptoms like tingling, and some auras start abruptly with vision loss. If you experience neurological symptoms for the first time, especially if they arrive suddenly, involve weakness on one side of the body, or don’t resolve within an hour, treating it as a medical emergency is the right call.
Aura and Long-Term Cardiovascular Risk
People who experience migraine with aura carry a modestly elevated risk of ischemic stroke compared to the general population. A large meta-analysis found that migraine with aura roughly doubled the risk of ischemic stroke (a pooled relative risk of 2.2), while migraine without aura did not meaningfully raise that risk above baseline. The association was strongest in women under 45, where the relative risk reached 3.7. Women with migraine with aura also showed about a twofold increase in the risk of heart attack, angina, or cardiovascular death.
These numbers sound alarming in relative terms, but the absolute risk remains low because ischemic stroke is uncommon in young, otherwise healthy people. Doubling a very small number still yields a small number. The practical implication is that if you have migraine with aura, managing other cardiovascular risk factors (blood pressure, smoking, cholesterol) becomes more important than it might otherwise be. Combined oral contraceptives, which independently raise stroke risk, are generally avoided in women who have migraine with aura for this reason.
What to Do During an Aura
Because auras typically last 5 to 60 minutes, most people learn to treat the aura phase as an early warning. If a headache usually follows, taking pain relief during the aura can sometimes reduce the severity of the migraine that comes after. Resting in a dim, quiet room during the aura itself helps many people, particularly when visual disturbances make it difficult to read, drive, or work. If you’re driving when an aura begins, pull over safely and wait for it to pass.
Keeping a record of your aura symptoms, including what they look like, how long they last, and whether they precede a headache, gives your doctor useful information for diagnosis. The International Headache Society’s diagnostic criteria specify that each individual aura symptom should last between 5 and 60 minutes. When multiple types of symptoms occur in sequence (for example, visual followed by sensory followed by speech), the total duration can extend to several hours. If your aura symptoms consistently last longer than 60 minutes each or don’t fit the typical pattern, that warrants further evaluation.