Abstracts

Rationale: To analyze possible cognitive differences between patients with mesial temporal lobe epilepsy (MTLE) and frontal lobe epilepsy (FLE). Methods: Attention, categorization and memory were assessed in 61 epilepsy patients: 25 MTLE (6 right and 19 left) and 36 FLE (17 right and 19 left) reported on their magnetic resonance (RM). Measures recorded for all the patients were time invested, number of errors (Trail Making Test – TMT; Cards - Behavioural Assessment of the Disexecutive Syndrome - BADS), conceptual level, perseverative responses and failures in the maintenance of the attitude (Wisconsin Card Sorting Test - WCST) and immediate recall, working memory, episodic codification and retrieval in both verbal and visual modalities (Wechsler Memory Scale Revised- WMS-R). Results: There were no significant differences on any variable when we focus on localization (MTLE versus FLT). When we attend to lateralization (right versus left hemisphere lesion) only one variable proved to be statistically significant; it refers to the number of errors committed on TMT part A, being the group with right hemisphere lesions (independently of their localization) who showed a poorer performance. More differences were found when we used as an independent variable the fact that patients had seizures during sleep. This showed us that patients with seizures during sleep need more time to complete attentional tasks (TMT-A and Cards 1 BADS) and had more difficulties on working memory (inverse digit and inverse visual memory) than patients with seizures during awake periods. Conclusions: It was neither localization (MTLE-FLE) nor lateralization (right-left) of seizures what better explains differences in our sample but the fact that patients had seizures during sleep. These patients were slower on attentional tasks and showed a poorer performance on working memory.