Dipole Source Localization and Low Resolution Electromagnetic Tomography(LORETA) of Interictal Spikes in Mesial and Lateral Temporal Lobe Epilepsy / 대한간질학회지

ABSTRACT

PURPOSE: To investigate the usefulness of dipole source localization (DSL) and low resolution electromagnetic tomography (LORETA) in localizing epileptic focus, we performed DSL and LORETA of interictal spikes in patients with mesial and lateral temporal lobe epilepsy (TLE). METHOD: We analyzed representative interictal spikes in 17 patients with TLE (9mesial TLE; 8lateral TLE). We used ASA3 (Advanced Neuro Technology, Netherlands) for DSL, voltage topography (VT) and LORETA of interictal spikes. RESULT: Most interictal spikes for analysis have their maximum amplitudes at electrode F7, 8 or T7, 8 except one patient with lateral TLE (P7). In mesial TLE, VT showed a maximum negative electrical field in ipsilateral fronto-temporal region. DSL showed dipole sources in ipsilateral anterior mesial temporal lobe (33.3%, 3/9), temporal pole (44.5%, 4/9), orbitofrontal (11.1%, 1/9) and anterior inferior frontal (11.1%, 1/9) regions. LORETA showed maximum current density in ipsilateral fronto-temporal or anterior-mid temporal areas with lateral temporal maximum. In lateral TLE, dipole sources were in ipsilateral temporal pole (62.5%, 5/8), thalamus (12.5%, 1/8) and in posterosuperior temporal area (2/8, 25%). VT of spikes at F7 or F8 showed similar results as those of mesial TLE while that of spikes at T7, T8 and P7 had a tendency of electrical fields more extending to the mid- and posterior temporal regions. LORETA showed more diffuse current distribution in whole temporal lobe (anterior to posterior) with lateral temporal maximum. CONCLUSION: The patterns of DSL and LORETA were somewhat helpful to differentiate mesial from lateral TLE. LORETA usually showed more diffuse activity beyond the epileptic focus.