Abstracts

Rationale: Partial epilepsy is the most common type of epilepsy syndrome at epilepsy clinic in Korea and it is more resistant to antiepileptic drugs. The purpose of this study is to investigate the epidemiologic characteristics and to compare the findings of scalp EEG and brain MRI in patients with partial epilepsy. Methods: We retrospectively analyzed data from 699 consecutive partial epilepsy patients with age of 11 to 60 years who visited to our hospital between January 2007 and January 2009. All of these patients underwent both scalp EEG and brain MRI. EEG of the patients were classified into normal, localized, biregional, lateralized, multiregional and generalized abnormalities and also divided into epileptiform and non-epileptiform abnormalities. Brain MRI lesions were classified to seven categories of hippocampal sclerosis, tumor, developmental abnormality, vascular malformation, stroke, infection, and others). The relationship between brain MRI and scalp EEG findings was analyzed too. Results: The mean age of the patients was 34.2±10.9 years and 381 (54.5%) were men. 484 (69.3%) had their age of onset of epilepsy under 20 years old. The mean duration of epilepsy was 16.7±9.5 (0.4 - 51.7 years). 499 (71.4%) had abnormal EEG findings (epileptiform discharge [372]; non-epileptiform discharge [127]) and 344 (49.2%) had brain MRI abnormalities. The main locations of epileptic focus are temporal (61.8%), frontal (20.1%), partietal (8.4%), occipital (2.8%), and others (7.0%). The 1st scalp EEG showed abnormalities in 378 (54.1%) and epileptiform discharges in 272 (38.9%). In patients who had two or more EEG recordings showed EEG abnormalities in 369 (68.3%) and epileptiform discharges in 212 (58.4%). Frequent brain MRI lesions were hippocampal sclerosis (42.4%), developmental abnormality (13.4%), tumor (9.9%) and stroke (9.9%). Abnormal EEG was found in 207 (58.3%) with normal MRI but in 256 (74.4%) with abnormal MRI. In patients with both abnormal EEG and MRI, the concordance rate of epileptic focus was 69.4%. The most predictive EEG findings for abnormal MRI were localized epileptiform discharges. Conclusions: Temporal lobe epilepsy was the most common type of partial epilepsy and their most common pathology was hippocampal sclerosis at the tertiary epilepsy center in Korea. The locations of EEG abnormalities were well correlated with the locations of MRI lesions.