A Parallel Study Of Epileptic Discharge And Abnormal Structure In Epileptic Patients

Purpose:To analyse the roles of active EEG and MRI in the diagnosisof epilepsy and its causes, and discuss the relationship between epileptic discharges and morphological abnormalities.Methods Ninety eight epileptic patients diagnosed by clinical semiology were studied by routine EEG(REEG), twenty-four hours active EEG(AEEG),CT scanning and MRI examination. The proportion of different seizure patterns, frequency and the age of onset were analysed. The positive findings of the four modalities and the distribution of the epileptic lesions were compared. The relationship between the epileptic discharges and the neuroradioligical lesions was analysed by chi-square test. The sentivity of MRI in diagnosing temporal lobe epilepsy and extratemporal lobe epilepsy was also analysed.Results:1.There were five cases of simple partial seizure in the ninety-eight patients (5. 1%), sixty-five cases of complex partial seizure( 66. 3%), in which twenty-three cases were followed by secondary generalized seizure, and twenty-eight cases of primary generalized seizures (28.6%). The frequence varied from once a year to thirty times a day , the median of frequence was once a month. The onset age ranged from one year of age to sixty-one years of age with the peak period untill thirty years of age.2.Routine EEG found epileptic discharge in forty patients while AEEG found in seventy-five patients, the positive ratio were 40.8% and 76.5%accordingly. AEEG provided 35. 7% more abnormal information than that of roution EEG. There were twenty-three cases of structural lesions by CT scanning and fifty-five cases of structural lesions by MRI , the positive ratio were 23. 5% and 56. 1% accordingly. The positive ratio of MRI was significantly higher than that of CT scaning(PK0. 001).3.Forty-two lesions were found by MRI in the sixty-three patients who had focal epileptic discharge. There were only five lesions among the fourteen patients whose epileptic discharge was bilateral. The abnormal ratio of focal epileptic discharge was higher than that of bilateral epileptic discharge. There were twenty-five patients who had lateral temporal discharge by EEG, and there were twelve temporal lobe lesions found by MRI which were accordant with epileptic discharge. The sensitivity of MRI was 48%. There were twenty-seven(62.8%) patients with epileptic discharge among those with normal MRI scanning,compared to forty-eight(87.3%) patients with epileptic discharge among those with abnormal MRI scanning. The positive ratio of epileptic discharge was higher than that of abnormal MRI scanning (P(0.05).Conclusions1.Complex partial seizure is a common type of epileptic seizure among the ninety-eight patients. The peak age of onset includes childhood and adolescence prior to thirty years of age.2.The positive ratio of AEEG reached 75. 6% and provided 35. 7% more abnormal information than that of routine EEG.AEEG is a useful tool in making diagnosis and in guiding therapy. MRT should be the first choice in finding epileptic structure abnormalities.3.There is correlation between epileptic discharge and structural 4abnormality. The occurrence of focal epileptic discharge may be a hint to abnormal structure. MRJ is sensitive to diagnosing temporal lobe epilepsy (sentivity 48%) , that is , it is easier to find epileptic lesions when there is epileptic discharge in temporal lobe.