Magnetoencephalographic correlates of different types of aura in temporal lobe epilepsy

Summary 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.