aura is a sensation which precedes an attack, such as an epileptic
seizure or a migraine
headache. In epilepsy,
the aura may precede the seizure by a few seconds or several
hours. The aura may include visual, auditory or olfactory
hallucinations (e.g. a particular smell), or just a "feeling"
that a seizure is coming. In migraine, the aura immediately
precedes the attack, and is usually visual (e.g. a halo of
light around the visual field).
The mechanisms causing an aura are poorly
understood. However, many people who suffer severe migraines
or severe epilepsy can use their aura as a warning sign which
may give them time to prepare for or even ward off a full
by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain