Abstracts

RATIONALE: Unilateral somatosensory and visual auras and motor seizures in one body-half indicate an epileptogenic area in the contralateral cortex. The precise localization of the epileptogenic area, however, is essential for a favorable surgical outcome.
METHODS: We examined the correlation between lateralizing signs in ictal semiology and surgical outcome after and 2 years in 42 patients with lesional epilepsies in the posterior (parieto-temporo-occipital) cortex.
RESULTS: 2 years after operation, none of the patients with only non-lateralizing semiology was seizure free while 47.6% (n=9/19) of the patients with either lateralizing auras or lateralizing seizures and 69.2% (n=9/13) of those with both lateralizing auras and lateralizing seizures were free of seizures (Engel-classification 1a or 1b; p=0.001). A logistic regression revealed, that the proportion of lateralizing seizures (p=0.004) and auras (p=0.018) to the total number of detected seizures and auras, respectively, is significantly related to the probability of a favorable surgical outcome. No patient (0/9) with lateralizing signs to the nonlesional hemisphere but 57.6% (19/39) of the patients without such false[dsquote] lateraliziation were free of seizures 2 years after operation (p=0.02).
CONCLUSIONS: The presence and frequency of ictal signs lateralizing to the lesional hemisphere and the absence of lateralization signs to the nonlesional hemisphere are highly predictive of a favorable outcome after surgical treatment of epilepsy in the posterior cortex. Our findings underline the great importance of the correct classification of epileptic auras and seizures in the presurgical epilepsy monitoring.