Nonlinear Dynamics of EEG in Pilocarpine-induced Status Epilepticus

J Korean Neurol Assoc > Volume 21(5); 2003 > Article

Journal of the Korean Neurological Association 2003;21(5): 507-512.

필로카르핀 간질중첩증 뇌파의 비선형 특성

정기영 , 김재문 김태우 박희동 김동욱

삼성서울병원 신경과학교실, 충남대학교병원 신경과학교실, 인제대학교 일산백병원 소아과학교실

Nonlinear Dynamics of EEG in Pilocarpine-induced Status Epilepticus

Ki-Young Jung

"Department of Neurology, Samsung Medical Center Department of Neurology, Chungnam National University Hospital, Institute for Brain Research, Chungnam National University* Department of Pediatrics, Ilsan Paik Hospital, Inje University†"

Abstract

"Background: Pilocarpine-induced status epilepticus (SE) model shows stereotypic EEG changes and behavioral characteristics. Although neuronal damages and therapeutic responses are also dependent on SE stages, the dynamical aspect of underlying neuronal interaction according to the SE stages has not been studied. We applied nonlinear analysis to the EEG recorded from pilocarpine-induced SE model to characterize nonlinear dynamics of different SE stage and to correlate therapeutic response with correlation dimension (D2).
Methods: Ten male Spraque-Dawley rats weighing 150-250g were used in this experiment. EEG was continuously recorded during SE and was classified into 6 stages as follows: baseline (BS), transitional (TR), discrete seizure (DS), continuous ictal discharges (CID), early periodic epileptiform discharges (EP), and late periodic epileptiform discharges (LP). High dose diazepam (20 mg/kg) was injected at the LP stage. Ses of 5 rats (control group) was controlled by diazepam and those of the rest (failed group) were failed to stop status epilepticus.
Results: Mean D2 value decreased progressively with fluctuation and was significantly different for SE stage (df=5, F=11.594, p=0.000). Independent t-test showed that the difference of D2 value between the controlled and failed group was significant at CID (df=40, t=2.591, p=0.013) and LP stage (df=49, t=- 2.425, p=0.019).
Conclusions: These results suggest that nonlinear dynamical change at the late half of SE stage is one of the contributing factors determining therapeutic responsiveness in pilocarpine-induced SE model.Key Words: Pilocarpine-induced status epilepticus, EEG stage, Nonlinear analysis, Dimension"