CLINICAL USEFULNESS OF THE DIPOLE TRACING METHOD FOR LOCALIZING INTERICTAL SPIKES IN PARTIAL EPILEPSY

Purpose: To clarify the clinical usefulness of the dipole tracing meth od in evaluation of interictal EEG spikes in patients with partial epi lepsy. Methods: Eight patients with partial epilepsy were studied. We compared the generator source of interictal spikes detected by the dip ole tracing method with the results of magnetic resonance imaging (MRI ), interictal/ictal measurement of cerebral blood flow (CBF) by single photon emission computed tomography (SPECT), interictal measurement o f glucose metabolism by positron emission tomography (PET) and invasiv e electrocorticogram (ECoG). Results: In 5 patients with mesial tempor al lobe epilepsy (TLE), including 3 patients who underwent standard te mporal lobectomy, the dipole tracing method showed results consistent with those of other examinations and better correlation with ECoG than with other noninvasive examinations. in a patient with mesial TLE who had defects in the skull due to previous surgery, the dipoles were lo cated more laterally than expected. In a patient with frontal lobe epi lepsy (FLE) who was finally proved to have an epileptogenic area in th e lateral frontal area, the spike dipoles were identified in the media l side of the frontal lobe. Conclusions: The dipole tracing method use d in the present study is useful for localizing epileptogenic areas in patients with mesial TLE. However, in patients with partial skull def ects and in those with FLE, the reliability of this method is still in accuracy of the lobe level.