The Combination Of EEG Methods To Localize Epileptogenic Foci

Objectives To localize epileptogenic foci by using EEG methods(including routine EEG, Video-EEC and twenty-four hour active EEG) and neuroimaging techniques and To evaluate the diagnostic value of the combination of EEG methods in localization of epileptogenic foci.Methods The clinical research reviewed the results of fifty epileptic patients (21 M, 29 F, av. 22.3y) on routine EEG(REEG),Video-EEG(VEEG),twenty-four hour active EEG (AEEG), CT. MRI (including fMRI, MRS) scanning and SPECT , MEG and PET examination. All the results of these modalities were compared with each other and the relationship between epileptic discharges of EEG and lesions of CT. MRI and SPECT was analyzed by using x 2 test. 30 patients who underwent surgery were followed up (av.13 months, 3?2 months) for assessment of seizure control.Results According to Engle' s classification of operative effect, 90. 0%(27/30) was classified as grade I ., II and III, 10. 0%(3/30) as grade IV. The lesions removed in grade I ~III were confirmed to be utility and lesions removed in grade I ~ II (83. 3%) were affirmed to be healing. There was no mortality in this series. The highest positive rate of epileptic foci (83.3%) was found in EEG, and the positive rate in MRI or CT was 13.3% or 6.7%. The rate of epileptic foci localized by SPECT was 16.7%. The positive rate of combination of EEG methods and neuroimaging technologies was perfectly 100.0%. Occurrence of typical evolutions was significantly correlated with qualitative and quantitative ictal/interictal EEG patterns, such as spike-wave discharges, intermittent spike-slow-wave focus, multiple asynchronous spike-wave foci, and nonconvulsive status epilepticus. The spike wave originated in the corresponding cerebrum cortex instead of hyperplastic and adherent arachnoid or tumor itself and the abnormality achieved by EEG was overlap or was in close proximity to the epileptic foci. EEG finding was linked with seizure characteristics and pathological results. The pathological finding of tissue samples was not especially and the damnification of conduction system was common on both primary and secondary epilepsy.Conclusions The number of localization epileptic foci was significantly different between EEC results and neuroimaging techniques. EEC is still a sensitive and effective method for epileptiform foci localization and the zone information comes from the nerve cell discharge, but not the occult vascular malformation, gliosis or focal neuron lesions. EEC is of important value to the classification of epilepsy and the diagnosis of primary epilepsy, and it may have the advantage in detecting and localizing epileptic foci of MRI, CT, and SPECT. There remains a correlative relation between electrophysiologic findings and pathological results. Combination of EEC technologies (Routine-EEC , Video~EEG> Active-EEC and EC0G-, DEEG) will improve the positive rate of epileptogenic area , which is useful for the precise diagnosis of epileptic focus and it may offer probable pathologic diagnosis for partial epilepsy, which is of great clinical significance.