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Dipole Density of Low-Frequency and Spike Magnetic Activity: A Reliable Procedure in Presurgical Evaluation of Temporal Lobe Epilepsy

Fernández, Alberto*; de Sola, Rafael G.; Amo, Carlos*; Turrero, Agustín; Zuluaga, Pilar; Maestú, Fernando*; Campo, Pablo*; Ortiz, Tomás*

Journal of Clinical Neurophysiology: July-August 2004 - Volume 21 - Issue 4 - p 254-266

Conventional visual analysis and dipole density analysis of magnetoencephalographic data for both spike and low-frequency magnetic activity were compared for presurgical evaluation in temporal lobe epilepsy (TLE) in a sample of 26 drug-resistant operated TLE patients. A series of logistic regression analyses were performed. Dipole density sensitivity was superior to visual localization analysis. Three separated logistic models were calculated for interictal spikes, low-frequency magnetic activity, and the combination of both measures. A combined interictal spike/low-frequency magnetic activity model predicted correctly the operated temporal lobe in all patients. Clear-cut criteria for the probability model are proposed that are valid for 92.3% of cases in the sample. The quantitative approach proposed by this study is an evidence-based model for presurgical evaluation of temporal lobe epilepsy, which improves previous magnetoencephalographic investigations and establishes working clinical criteria for patient evaluation in TLE.

*Centro MEG Dr. Pérez Modrego, Universidad Complutense de Madrid; †Servicio de Neurocirugía, Hospital Universitario de la Princesa; and ‡Departamento de Bioestadística e I.O., Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain

Address correspondence and reprint requests to Dr. Tomás Ortiz Alonso, Centro MEG Dr. Pérez-Modrego, Facultad de Medicina, Pabellón 8, Universidad Complutense de Madrid; Madrid, Spain; e-mail:

Copyright © 2004 American Clinical Neurophysiology Society