Abstracts

Rationale: It is a common assumption that auras provide a clue of focal seizure onset and the seizure onset zone is closely related to the lesion in a patient with an isolated lesion. We investigated the value of aura in localization and lateralization of epileptogenic focus in patients with lobar epilepsy defined by an isolated lesion.Methods: We selected the patient with a single lesion on MRI, who had visited the outpatient epilepsy clinic of Severance Hospital. The lesion should be confined to unilateral and single lobe (the patients with bilateral asymmetric hippocampal sclerosis were included), and the scalp EEG finding not be discordant with location and side of the lesion. The auras were classified into thirteen categories: epigastric, autonomic, emotional, cephalic sensation, vestibular, psychic, visual, somatosensory, dysphasic, olfactory, whole body sensation, auditory, and other. The lobar locations of the lesion were classified into mesial temporal, lateral temporal, frontal, parietal, and occipital lobes.Results: The study comprised 284 patients. One hundred and eighty three patients (64.4%) experienced 282 auras with an average of 1.54 auras per patient. Mesial temporal lobe cases were most common (138 cases, 48.6%) and followed by frontal (67 cases, 23.6%), lateral temporal (56 cases, 19.7%), parietal (18 cases, 6.3%), and occipital (5 cases, 1.8%) lobe cases. Epigastric (p=0.007), autonomic (0.015), and psychic (p=0.006) auras were significantly more frequent in mesial temporal lobe epilepsy. However, there was no significant difference between the mesial and lateral temporal lobe epilepsy. The patients with frontal lobe epilepsy more frequently reported that they do not experience any aura, compared to the patients with other lobar epilepsies (65.7% vs. 26.7%). Somatosensory auras were more frequent in parietal lobe epilepsy (16.7%), and visual auras common in both parietal (22.2%) and occipital (40.0%) lobe epilepsy. Vestibular and visual (p=0.002), epigastric and autonomic (p=0.007), and olfactory and autonomic (p=0.043) auras occurred more coincidentally. Dysphasia was more frequently found in left-sided epilepsy (n=0 vs. n=16), but vestibular and olfactory auras were more common in right-sided epilepsy (9 vs. 2; 6 vs. 1).Conclusions: Our results suggest that the type of aura can provide useful localizing information, and are generally consistent with previous studies which investigated auras in surgical cases.