Semiology, Video-Electroencephalography Monitoring, Neuroimaging, and Neuropsychological Functions in Lateralization/Localization in Extratemporal Lobe Epilepsies

Abstract

Objectives:The present study aimed to determine the semiological signs having high lateralizing/localizing value of epileptogenic area (EA) using video-electroencephalography monitoring (VEM), neuroimaging, and neuropsychological tests in patients with extratemporal lobe epilepsy (ETLE) and to investigate the correlation between these methods.Methods:We enrolled patients who were admitted to the VEM unit between October 2006 and June 2012 due to ETLE. In total, 198 seizures of 34 patients, who were monitored for 24–120 h, were evaluated in detail by two observers. In accordance with the epilepsy protocol, all patients underwent cranial magnetic resonance imaging for anatomic localization and F-18-fluorodeoxyglucose positron emission tomography for functional localization due to drug-resistant epilepsy. Neuropsychological tests were performed by an experienced psychologist for frontal and parietal lobe localizations.Results:The lateralization of EA using semiological signs could be performed in 67.6% of the patients. The signs having the highest lateralizing value were version, unilateral tonic activity, and unilateral clonic activity and those having the lowest lateralizing value were unilateral dystonia, unilateral smiling, unilateral automatism, and sensorial aura. Correlation analysis between anatomical functional foci determined by semiological signs and the results of ictal/interictal electroencephalography (EEG), neuroimaging, and neuropsychological tests could not be performed due to inadequate patient number. Nevertheless, only three patients (8.82%) having the same EA were detected by both semiological signs and other methods.Conclusion:Our results suggest that the identification of epileptogenic focus in ETLEs is difficult despite multidisciplinary methods. We concluded that the most supportive diagnostic methods in identifying EA were interictal/ictal EEG, neuroimaging, and neuropsychological evaluation.

Keywords

• extratemporal lobe epilepsy
• lateralizing/localizing signs
• multidisciplinary approach
• video-electroencephalography monitoring