"For me, it was a smell of bananas. When I smelt that, I'd just sit down wherever I was before the blackness came."
– Vusi Mahlasela
What is an aura?
Many seizures start with a warning symptom, or epileptic "aura". In some circumstances the aura itself may be the entire extent of the epileptic episode, in others there is progression to a full-blown seizure. (NB: the specific medical term “aura” should not be confused with the mystical emanation that supposedly surrounds a living body. Both words come from the Greek for “breeze” or “breath”. ) Experienced epileptics learn to recognise the aura, and can prepare themselves for the seizure – by lying down in a safe pla
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ce, for example.
People experience widely varied auras. For some, the aura is emotional: a sudden feeling of anxiety, tension or fear. For others, it takes the form of a specific sensation that only they can feel, such as cooling or warming, a particular taste, or a sound (sometimes musical). In some cases the aura appears as a particular odour, often unpleasant, such as burning rubber. The aura can manifest in certain people as a feeling of deja vu – where people or places appear strangely familiar; or its opposite, jamais vu – where people or situations that should be familiar, appear strange. Frequently, the aura is something that the person finds impossible to describe – simply a “funny feeling.”
What the aura can tell us
The presence of an aura implies that the seizure starts in one part of the brain, and is therefore a "partial" seizure. This may go on to become a generalised convulsion (a secondarily generalised seizure) and sometimes this is so rapid that the aura is not apparent. Primarily generalised seizures seem to involve both hemispheres of the brain simultaneously and do not start with a true aura.
The quality of the aura will indicate which particular region of the brain is being abnormally activated. For example, a hallucination of smell is most likely to originate in one of the temporal lobes, whereas involuntary twitching of one hand (not really an aura as it is not a sensation, but having exactly the same significance) will suggest a focus in the opposite frontal lobe.
Information of this sort will prompt a careful search in these parts of the brain for underlying lesions that might be causing the seizures in the first place. Also, the fact that the seizure is a partial one will mean that certain medications (and in some cases, surgery) are more likely to be effective than in a primarily generalized seizure, where an aura will not be present.
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