FAST RIPPLE RATE INDICATES THE SEVERITY OF EPILEPSY: COMPARISON OF TWO CHRONIC EPILEPSY MODELS
Abstract number :
3.003
Submission category :
Year :
2002
Submission ID :
1821
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Anatol Bragin, Andrey Mazarati, Don Chin, Raman Sankar, Charles L. Wislon, Claude Wasterlain, Jerome Engel. Department of Neurology, UCLA School of Medicine, Los Angeles, CA; Department of Pediatrics, UCLA School of Medicine, Los Angeles, CA; Brain Resear
RATIONALE: To investigate the relationship between severity of status epilepticus and severity of chronic epilepsy in two rat models.
METHODS: Self sustained status epilepticus (SSSE) and kainic acid status (KASE) models of chronic epilepsy were compared in the following ways: severity of initial status epilepticus, characteristics of high frequency oscillations (ripple and fast ripples), serum neuron specific enolase (sNSE) assay during interictal period, and severity of chronic, recurrent spontaneous seizures.
RESULTS: The pattern of electrical activity during status was similar in both models of epilepsy, however the rate of seizures was higher during SSSE and status itself was longer. The level of sNSE after SSSE was significantly (35%) higher than after KASE, reflecting greater neuronal injury. There were no significant differences in the percent of rats developing spontaneous seizures after status, however the mean rate of seizures per month in the SSSE group was 121+13 and in the KASE group 4.2[plusminus]2.7. The rate of EEG interictal spikes was significantly higher in the SSSE group as well as the rate of occurrence of high frequency oscillations (Ripples and Fast Ripples (FR)). There was no difference in the amplitude distribution of high frequency oscillations between the two models of epilepsy. In the KA group, Ripple oscillations were recorded bilaterally while FR were found only in the dentate gyrus (DG) and entorhinal cortex (EC) ipsilateral to KA injection. In the SSSE group, both Ripples and FR were found to be generated bilaterally in the DG and EC. In both models of epilepsy, FR oscillations were recorded at seizure onset.
CONCLUSIONS: The severity of status epilepticus determines the severity of the epileptic seizures. The rate of occurrence and bilateral distribution of FR within hippocampal- entorhinal circuitry correlates with the severity of epilepsy.
[Supported by: NIH grants NS02808, NS33310, NS11315, NS01792]