뇌전증 환자에서 항뇌전증약물의 효능 및 수술 후 예후 평가

Abstract

Recently quantitative analysis of electroencephalography (EEG) has been very useful to understand the mechanism and pathogenesis of epilepsy. And EEG and electrocorticography(ECoG) recording has been the most important role in epilepsy surgery. The author analyzed the quantitative EEG to estimate the effect of levetiracetam (LEV) on cognition, and the clinical implication of ECoG in epilepsy surgery. In the first part, the author investigated the cognitive effect of LEV monotherapy with quantitative EEG analysis and neuropsychological (NP) tests. Twenty-two drug-naive epilepsy patients were enrolled. EEG recordings were performed before and after LEV therapy. Relative power of discrete frequency bands was computed, as well as alpha peak frequency (APF) at occipital electrodes. Eighteen patients performed a battery of NP tests twice across LEV treatment. LEV therapy decreased the power of delta (1-3 Hz, p < 0.01) and theta (3-7 Hz, p < 0.05) bands and increased that of alpha-2 (10-13 Hz, p < 0.05) and beta-2 (19-24 Hz, p < 0.05) bands. Region-specific spectral change was observed: delta power change was significant in fronto-polar region, theta in anterior region, alpha-2 in broad region, and beta-2 in left fronto-central region. APF change was not significant. Improvement in diverse NP tests requiring attention, working memory, language and executive function was observed. Change in theta, alpha-2, and beta-2 power was correlated with improvement in several NP tests. LEV was associated with acceleration of background EEG frequencies and improved cognitive function. Change in frequency band power could predict improvement in several cognitive domains across LEV therapy. Combined study of quantitative EEG analysis and NP tests can be useful in identifying cognitive effect of antiepileptic drugs. In the second part, Mesial temporal lobe epilepsy (MTLE) is the most common surgically remediable human epilepsy syndrome, and hippocampal sclerosis (HS) is the most frequently encountered lesion in patients with MTLE. Postsurgical outcome studies of patients with mesial temporal lobe epilepsy (MTLE) showed considerable amount of seizure recurrence in a postoperative follow-up. The precisional identification of predictive factors of long-term surgical outcome is important and useful to improve surgical outcome of MTLE. The author aimed to assess the prognostic factors of long-term postoperative outcome including clinical characteristics, the presence of seizure recurrence, surgical methods, and pathology of resected lateral temporal tissue in MTLE patients. Out of 588 patients who underwent respective surgery, 273 MTLE patients met the following inclusion criteria as MTLE: (1) a temporal epileptic focus with typical complex partial seizures, (2) hippocampal sclerosis which was confirmed by MRI and histopathology. All patients had at least 2 years of postsurgical follow-up (ranged 2 to 17 years). Clinical characteristics and results of diagnostic tests were included as prognostic factors. Univariate and multiple logistic regression models were used to verify presurgical, surgical, and postsurgical factors that are independently predictive of the long-term outcome of MTLE patients. And Kaplan-Meier survival analysis and Cox proportional hazards regression model were applied to estimate time-to-seizure curves and predictive values. Multivariate logistic regression analysis revealed that independent factors for prediction of unfavorable seizure outcome: seizure recurrence within first postoperative year (p=0.001), and existence of cortical dysplasia in lateral temporal lobe that was confirmed by histopathology (p=0.033). In conclusion, the absence of cortical dysplasia in lateral temporal lobe was an independent prognostic factor for favorable surgical outcome in this study. The author also observed that the seizure recurrence within first postoperative year was the predictor for poor surgical outcome.