Migraine Aura Duration and Laterality
Migraine auras typically last 5-60 minutes per individual symptom, and while they are characteristically unilateral (affecting one side of the visual field), they can present bilaterally in approximately 14% of cases. 1
Duration of Migraine Auras
Each individual aura symptom lasts between 5-60 minutes, which is a defining diagnostic criterion according to the International Classification of Headache Disorders (ICHD-3). 1
The visual symptoms develop gradually over at least 5 minutes, which is a critical feature that helps distinguish migraine aura from more dangerous conditions like transient ischemic attacks (TIAs), where symptoms appear suddenly and simultaneously. 1, 2
When multiple aura symptoms occur during a single attack, they typically appear in succession rather than simultaneously, and the total acceptable duration can extend (for example, if 3 symptoms occur, the maximum duration could be 3 × 60 minutes = 180 minutes). 1
Motor symptoms are an exception and may persist up to 72 hours, though these are rare. 1
Research confirms that the majority of patients experience aura durations between 5-35 minutes, with no typical auras lasting more than 60 minutes. 3
Unilateral vs. Bilateral Presentation
At least one aura symptom must be unilateral to meet diagnostic criteria for migraine with aura, making unilateral presentation the characteristic pattern. 1
However, bilateral auras do occur in approximately 14% of patients with visual aura, so bilateral presentation does not exclude the diagnosis. 3
Among patients with unilateral auras, the visual symptoms may appear either ipsilateral (same side) or contralateral (opposite side) to the subsequent headache, with contralateral presentation being slightly more common (47% vs. 39%). 3
The unilateral nature typically refers to one side of the visual field in both eyes (homonymous visual field defect), not one eye versus the other, since the visual cortex processes information from both eyes together. 2
Clinical Implications
Visual aura is the most common type, occurring in over 90% of patients who experience aura, typically manifesting as bright scintillating lights, zigzag lines (fortification spectra), or scotomas (blind spots). 2, 4, 3
The gradual spreading pattern over 5-20 minutes is pathognomonic and reflects the underlying cortical spreading depression mechanism. 2, 4
Complete reversibility is mandatory for diagnosis—any persistent neurological deficit beyond one hour (except motor symptoms) should prompt urgent evaluation for alternative diagnoses such as stroke. 1, 2
Important Caveats
If a patient describes sudden, simultaneous onset of visual symptoms rather than gradual spreading, consider TIA or other vascular events instead of migraine. 1
First-time aura presentations warrant careful evaluation, especially if there are no visual symptoms, if symptoms correspond to a specific vascular territory, or if the patient cannot clearly describe gradual onset. 4
Aura can occur without subsequent headache (acephalgic migraine), which is diagnostically valid but requires at least 2 typical episodes to confirm the pattern. 5, 6, 7