An aura is a brief feeling or sensation, lasting seconds to minutes, occurring immediately before the onset of a paroxysmal neurological event, such as an epileptic seizure or a migraine attack (migraine with aura, "classical migraine"), "warning" of its imminent presentation, although auras may also occur in isolation. An aura indicates the focal onset of neurological dysfunction. Auras are exclusively subjective, and may be entirely sensory, such as the fortification spectra (teichopsia) of migraine, or more complex, labeled psychosensory or experiential, as in certain seizures.
Epileptic auras may be classified into subgroups:
- for example, paresthesia.
- hallucinations, illusions; occipital or temporal origin; complex hallucinations and a "tunnel vision" phenomenon are exclusive to seizures of anteromedial temporal and occipitotemporal origin, whereas elementary hallucinations, illusions, and visual loss are common to both occipital and temporal lobe seizures.
- may indicate an origin in the superior temporal gyrus.
- parosmia may occur in seizures of medial temporal lobe origin (uncus; uncinate fits).
- rising epigastric sensation (visceral aura) of temporal lobe epilepsy.
- complex hallucinations or illusions that usually affect different senses, e.g., distortions of familiarity, such as déjà vu or jamais vu auras of focal-onset epilepsy, indicative of temporal lobe and limbic onset respectively.
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Palmini A, Gloor P. The localizing value of auras in partial seizures.
Neurology 1992; 42: 801-808