Current-Source Dipole of Anterior Temporal Spikes: Clinical Significance of Orientation

J Korean Neurol Assoc > Volume 29(3); 2011 > Article

Journal of the Korean Neurological Association 2011;29(3): 165-171.

앞관자엽극파의 쌍극자전류원: 방향의 임상적 의미

김영수, 권오영a,b 정석원a 손승남a 김수경a 강희영a 박기종a,b 최낙천a,b 임병훈a,b

경상대학교 의학전문대학원 신경과학교실a, 경상대학교 건강과학연구원b

Current-Source Dipole of Anterior Temporal Spikes: Clinical Significance of Orientation

Young-Soo Kim

Department of Neurologya, Gyeongsang National University School of Medicine, Jinju, KoreaGyeongsang Institute of Health Scienceb, Gyeongsang National University, Jinju, Korea

Abstract

Background: The voltage topography of temporal spikes has two distinct patterns, designated type I and type II; the orientation of the current-dipole source (O-CDS) of type I spikes tends to be oblique, while that of type II spikes tends to be horizontal. The purpose of this study was to identify the effects of the O-CDS of anterior temporal spikes on clinical factors including onset age, seizure frequency, secondary generalization, disease duration, intractability, polytherapy, febrile seizure, hippocampal sclerosis, and neocortical-temporal aura.
Methods: We examined the scalp electroencephalograms of 24 patients with temporal lobe epilepsy (TLE) and anterior temporal spikes. A spatiotemporal dipole model was applied to determine the O-CDS of the averaged spikes in each patient. We performed current-source analysis of multiple spatiotemporal dipole models using Brain Electrical Source Analysis software. The patients were divided into two subgroups according to their O-CDS pattern: oblique and horizontal. Clinical factors were compared between the two groups.
Results: Sixteen patients were classified into the oblique group, and 8 patients into the horizontal group. A neocortical-temporal aura was more commonly observed in the horizontal group (p<0.05), while drug-resistance tendencies were more commonly observed in the oblique group (p<0.1).
Conclusions: The horizontal O-CDS of anterior temporal spikes may be more frequently associated with a neocortical-temporal aura than the oblique O-CDS in TLE. In addition, the oblique O-CDS pattern suggests a tendency toward drug resistance. The findings of this study imply that the oblique O-CDS pattern of anterior temporal spikes may provide additional electrophysiologic information regarding drug-resistant mesial TLE. KeyWords: Electroencephalography, Anterior temporal spikes, Current-dipole source, Temporal lobe epilepsy, Aura, Drug-resistant epilepsy