Visual auras can be:
- Scotoma; the area of decreased or lost vision.
- Phosphenes; brief flashes of light.
- Blurry vision.
- Wavy lines: like seen through a heat wave
- Other visual symptoms
- numbness or tingling
- pins and needles
- weakness on one side of the body
What is the cause?
The scientific term cortical spreading depression (CSD) describes a local disturbance of the brain function that is characterised by a transient and local suppression (depression) of the spontaneous electrical activity in thecortex (cortical) that moves slowly across this brain region (spreading). Aristides A.P. Leão, a Brazilian studying for a PhD at Harvard University was the first to describe this phenomenon in 1944 (Figure 1). He made this discovery while studying epilepsy. One year later, a better characterisation of CSD, especially of its progression, allowed Leão and his colleague R.S. Morison to propose, for the first time, that the malfunction of cortical nerve cells suspected to cause the aura might well be CSD. Indeed, both the suspected nervous malfunction and CSD shared surprisingly many common properties.Migraine Trust
Criteria for migraine with aura:
- A. At least 2 attacks fulfilling criteria B–D.
- B. Aura consisting of at least one of the following, but no motor weakness*:
- 1.Fully reversible visual symptoms including positive features (e.g., flickering lights, spots or lines) and/or negative features (i.e., loss of vision).
- 2. Fully reversible sensory symptoms including positive features (i.e., pins and needles) and/or negative features (i.e., numbness).
- 3. Fully reversible dysphasic speech disturbance.
- C. At least two of the following:
- 1. Homonymous visual symptoms1 and/or unilateral sensory symptoms.
- 2. At least one aura symptom develops gradually over ≥5 minutes and/or different aura symptoms occur in succession over ≥5 minutes.
- 3. Each symptom lasts ≥5 and D. Headache fulfilling criteria B–D for 1.1 Migraine without aura begins during the aura or follows aura within 60 minutes.
- E. Not attributed to another disorder.