Magnetoencephalographic correlates of different types of aura in temporal lobe epilepsy

Abstract

Purpose: To estimate magnetoencephalography (MEG) correlates of different types of aura in temporal lobe epilepsy (TLE). Methods: MEG study was performed on 57 patients (26 male and 31 female) with TLE, whose ages ranged from 14-46 years (mean 27 years). Interictal magnetoencephalograms showing discharges were analyzed, and spike-dipole clusters were categorized into left and right inferotemporal-horizontal (IH) and superotemporal-vertical (SV) types. Auras were classified into autonomic, auditory, and psychic seizures. The correlation between the four types of interictal spike-dipole and three types of aura was analyzed using Fisher's exact probability test. Results: IH type correlated with autonomic seizures (p = 0.0004), whereas SV type correlated with both auditory (p = 0.0002) and psychic seizures (p = 0.042). When subdivided into left and right, left IH type correlated with autonomic seizures (p = 0.046), but right IH type did not. Right SV type correlated with both auditory (p = 0.014) and psychic seizures (p = 0.002), but left SV did not correlate with either. Both types did not correlate with "no aura." Conclusions: Using our proposed classification of spike-dipoles, MEG distinguishes auras of mesial temporal origin from those of lateral temporal region. Furthermore, by adopting our classification, laterality of spike-dipoles is clearly demonstrated in auditory and psychic seizures. © 2010 International League Against Epilepsy.