Lateralizing value of semiology in medial temporal lobe epilepsy.

Objective: Analysing the clinical characteristics of seizures constitutes a fundamental aspect of the presurgical evaluation of patients with medial temporal lobe epilepsy and unilateral hippocampal sclerosis (MTLE-HS), the most frequent form of focal epilepsy accessible to surgery. We sought to retrospectively determine whether objective manifestations could have a reliable lateralizing value in a large population of MTLE-HS patients and if their presence could help to identify those patients who would be seizure free after surgery.

Methods: We analysed the frequency and predictive lateralizing value of objective ictal and postictal signs in 391 patients with MTLE-HS (183 left/208 right). Data were derived from chart review and not from blinded videoEEG analysis. Correlation between the presence of reliable lateralizing signs and postoperative outcome was performed in a subgroup of 302 patients who underwent surgery.

Results: Contralateral dystonic posturing was the most frequent and reliable lateralizing sign that correctly lateralized the focus in 96% of patients. Unilateral head/eye deviation was noted in 42% of the patients and predicted unilateral focus in 67%. Ipsilateral postictal nose wiping, contralateral clonus and hypokinesia correctly lateralized the focus in 75%, 81%, respectively, and 100 of patients but were less frequently depicted. Postictal aphasia was a strong lateralizing sign for left MLE-HS. The presence of reliable lateralizing signs was not a predictor of seizure freedom.

Conclusions: Seizure semiology is a simple tool that may permit reliable lateralization of the seizure focus in MTLE-HS. The presence of reliable lateralizing signs is not associated with a better postoperative outcome.