Migraine aura is a fully reversible condition that either precedes or commences with the onset of head pain.
It affects up to 20% of migraineurs, and in some rarer cases my appear without headache.
It is now understood to be related to a phenomenon called "cortical spreading depression". This tsunami of decreased blood flow causes decreased nerve activity in the brain. It begins in the occipital lobe (visual cortex) and spreads to the front quite slowly (estimated 3mm/minute).
First observed in animals in the 1940's, recent MRI and PET scan studies show it is a common feature of aura.
Is this the brains way of limiting the overactivity coming from the trigeminocervical nucleus? A lot remains to be understood about the relationship between different aspects of migraine.
Typical aura may involve:
Visual disturbance: bright flashing lights, zig zag lines,
scotoma (loss of part of visual
field/blind spot), difficulty focussing
Paraesthesia - pins and needles/tingling, numbness
Parosmia - altered smell
Dysarthria - difficulty speaking
Dysphagia - difficulty swallowing
Dysgeusia - altered taste
Hypokinesia - decreased muslce function
Paramnesia - deja vu, Jamaiv vu
Auditory hallucinations - tinnitus, buzzing
Altered cognitive function
It should be noted that if any of these symptoms appear for the first time, or they are regular features but do not fully resolve you should seek and assessment with a medical practitioner. However rare, any of these can be signs of more significant pathology and appropriate investigation is warranted.
Roger O'Toole is the Director and Senior Clinician of the Melbourne Headache Clinic and has over 10 years experience as a physiotherapist.