MAGNETOENCEPHALOGRAPHIC EVALUATION OF ANTERIOR CORPUS CALLOSOTOMY FORINTRACTABLE EPILEPSY IN A PATIENT WITH LENNOX-GASTAUT-SYNDROME

We analyzed the preoperative and postoperative interictal magnetoencep halographic (MEG) patterns in a 32-year-old woman with Lennox-Gastaut syndrome who underwent an anterior corpus callosotomy (CC). A 37-chann el biomagnetometer was used for the simultaneous recording of electroe ncephalogram (EEG) and MEG. Preoperatively, interictal EEG demonstrate d a bilaterally synchronous spike and slow wave bursts with a maximum amplitude on the bifrontal region. The waveforms of the MEG were simil ar but did not completely correspond to those of the EEG. The estimate d equivalent current dipoles (ECDs) originating from bilaterally synch ronous paroxysmal discharges formed a dense cluster on the bilateral f rontal lobes, especially on the deep midfrontal region. After anterior CC, MEG disclosed a marked reduction of the number of ECDs. The preop erative MEG patterns were thought to be representative of interhemisph eric synchrony as a large dipole orientation, and these MEG paterns we re partly disrupted by anterior CC. (C) 1998 by Elsevier Science Inc. All rights reserved.