Abstracts

Rationale: Differentiating of neocortical temporal lobe epilepsy (NTLE) from combined neocortical-temporal onset of seizure with mesial TLE (mesio-neocortical TLE, MNTLE) is critical to achieve good surgical outcome and avoid unnecessary memory impairments. However, its identification remains rather difficult. Methods: We enrolled 88 TLE patients who underwent intracranial EEG monitoring and had subsequently undergone surgery as MNTLE or NTLE (a postoperative period of ? 2 years). Their data from comprehenisve presurgical evaluation were reviewed to characterize the MNTLE and to compare the surgical outcome between MNTLE and NTLE. Results: Overall seizure-free rate was 73.8% (mean period, 9.7 years, ranged 2-15), which was not different between MNTLE (n=35) and NTLE (n=53). MNTLE patients had higher frequencies of a localized temporal hypometabolism on positron emission tomography (PET) and lower recognition scores in non-verbal memory was as compared with NTLE. A half of MNTLE showed a localized regions with ictal hyperperfusion on single photon emission computed tomography. NTLE patients had lower frequencies of aura and more frequent generalized tonic-clonic seizures. There were no differences in patients characteristics, scalp EEG findings, the presence of MRI lesions, and Wada asymmetry between groups. Multivariate analysis revealed that the presence of aura or a focal lesion of MRI, and localized temporal hypometabolism were independent factors to characterize MNTLE. Conclusions: Long-term surgical outcome were similarly excellent in both MNTLE and NTLE. Our findings suggest that semiology as well as MRI and PET findings may be important factors to differentiate MNTLE from NTLE and to accomplish the postoperative good outcome.