JERK-LOCKED BACK AVERAGING AND DIPOLE SOURCE LOCALIZATION OF MAGNETOENCEPHALOGRAPHIC TRANSIENTS IN A PATIENT WITH EPILEPSIA PARTIALIS CONTINUA

In order to localize the generator site of epileptiform discharges, we applied the techniques of jerk-locked back averaging (JBA) of magneto encephalographic (MEG) activities and dipole source localization in a patient with epilepsia partialis continua (EPC), who showed continuous , focal myoclonic jerks in the right arm. The myoclonic discharges in the right thenar muscle were used as a trigger pulse. JBA revealed con sistent EEG and MEG transients that coincided consistently and constan tly preceded the myoclonic jerks. The estimated dipoles of MEG were lo calized in a restricted area in the left precentral area, which closel y correlated with the area of epileptic discharges recorded in electro corticography. Therefore, JBA of MEG is considered to be a useful non- invasive method for localizing the epileptogenic area in EPC. (C) 1997 Elsevier Science ireland Ltd.