PURPOSE: To investigate the origin of frontal lobe dysfunction identified by the Wisconsin Card Sorting Test (WCST) in mesial temporal lobe epilepsy (MTLE). METHODS: We included 85 patients with unilateral MTLE and 34 patients with neocortical temporal lobe epilepsy (NTLE). We included only MTLE patients who postoperatively became seizure free at least for 1 year. Comparisons were made on the WCST performance between MTLE and NTLE and between preoperative and postoperative test in MTLE. Standardized regression based (SRB) methodology was used for correcting test-retest bias. RESULTS: 1) There were no significant differences in frontal lobe dysfunction defined as more than 17 perseverative errors between MTLE (64%) and NTLE (76%). 2) No significant differences in WCST performance between MTLE and NTLE were noted, except in categories completed (p=0.05). NTLE achieved significantly fewer categories than MTLE. 3) The proportions of patients with MTLE who postoperatively showed a clinically meaningful improvement on WCST performance were higher than those who displayed a significant decline. In case of perseverative responses, 52% of patients with MTLE postoperatively showed an improvement whereas 18% displayed a decline. 4) Postoperatively, mean values of perseverative responses and total errors were significantly decreased (p<0.05). 5) Significant negative correlations were found between preoperative WCST performance and postoperative SRB change scores for WCST (r=-0.3~-0.4, p<0.05). CONCLUSIONS: Our results could not be explained by any one of 'neural noise' or 'hippocampal' hypothesis. Our data suggest that poor WCST performance in patients with MTLE might be attributed to dysfunction of neural system including both hippocampus and frontal lobe cortex. Further studies are needed to make new hypothesis.
Bias (Epidemiology) ; Epilepsy, Temporal Lobe* ; Frontal Lobe ; Hippocampus ; Humans ; Seizures ; Temporal Lobe* ; Wisconsin*

PURPOSE: Hippocampal sclerosis is known to strongly correlate with medical intractability of temporal lobe epilepsy. However, the informations about this have been biased due to improper selection of the sampling obtained from severe cases of tertiary epilepsy center and surgical epilepsy field. We tried to investigate the influence of hippocampal sclerosis on the pharmacoresistance in temporal lobe epilepsy by group comparison study. METHODS: The fifty patients with complex partial seizures of temporal lobe origin, and temporal spike on EEG and/or hippocampal sclerosis on brain MRI were selected. Follow-up period of them were more than 2 years. The patients who had a seizure or seizures during the last 1-year period and had already been in adequate doses of two or more antiepileptic drugs were considered to be poorly controlled epileptics. RESULTS: Five of 17 patients without hippocampal sclerosis (29. 4%) and 24 of 33 patients with hippocampal sclerosis (72.7%) were poorly controlled by medication and the difference was significant (p=0.003, chi-square). Other factors, including sex, age of onset, febrile convulsion, secondary generalization, familial history of epilepsy, duration of disease, and delay of initial therapy had no significant effects on medical response (p>0.05). The only independent predictor of intractable epilepsy after multiple logistic regression analysis was also hippocampal sclerosis (p=0.005). CONCLUSION: Medical response in temporal lobe epilepsy was significantly associated with hippocampal sclerosis. Hippocampal sclerosis on brain MRI itself may be a crucial factor determining pharmacoresistance of temporal lobe epilepsy.
Age of Onset ; Anticonvulsants ; Bias (Epidemiology) ; Brain ; Drug Resistance ; Electroencephalography ; Epilepsy ; Epilepsy, Complex Partial ; Epilepsy, Temporal Lobe* ; Follow-Up Studies ; Generalization (Psychology) ; Hippocampus ; Humans ; Logistic Models ; Magnetic Resonance Imaging* ; Sclerosis* ; Seizures ; Seizures, Febrile ; Temporal Lobe*

We tried to investigate the incidence and the clinical profile of intractable epilepsy with hippocampal atrophy and ictal onset zones located in areas other than the hippocampus (extra-medial-temporal epilepsy; EMTE). We included patients who had hippocampal atrophy confirmed by MRI but with extra-medial-temporal ictal onset zones as verified by invasive intracranial electrodes or video-EEG monitoring. The case histories, interictal EEG, ictal semiology, other MRI findings in addition to hippocampal atrophy, and results of ictal SPECT and PET scans were evaluated. Results were compared with those of surgically proven medial temporal lobe epilepsy with hippocampal atrophy recruited during the same period. 8.5% of the intractable epilepsy patients with hippocampal atrophy had extra-medial temporal epileptogenic zones. A history of encephalitis and hemiconvulsion-hemiparesis were significantly common in the EMTE group. Most of the interictal EEGs of EMTE patients showed extratemporal irritative zones. MRI, ictal SPECT, and FDG-PET seemed to be helpful at localizing the true epileptogenic zones. The predominant EMTE seizure type was focal motor seizure with secondary generalization. Some portion of intractable epilepsy patients with hippocampal atrophy had extra-medial-temporal epileptogenic foci and careful analysis of semiology and neuroimagings could yield clues to correct diagnosis.
Adult ; Atrophy ; Electroencephalography ; Epilepsy/physiopathology ; Epilepsy/epidemiology* ; Epilepsy/diagnosis ; Epilepsy, Temporal Lobe/epidemiology ; Hippocampus/pathology* ; Human ; Incidence ; Magnetic Resonance Imaging ; Retrospective Studies ; Tomography, Emission-Computed ; Tomography, Emission-Computed, Single-Photon