Serial position curve and semantic facilitation in patients with mesial temporal lobe epilepsy

Abstract

We investigated the serial position curve and semantic facilitation effect in patients with left and right mesial temporal lobe epilepsy (MTLE) with hipocampal sclerosis compared to a matched control group. Subjects (L-MTLE = 19, R-MTLE = 15, and controls = 21) were assessed by recalling word lists either with the three middle words semantically related or not. The total number of words recalled from both types of lists did not differ between groups. Recency was preserved, showing that short-term memory (phonological loop) is not affected in these patients. Primacy was equally present for the lists with no semantic relationships in all groups, but was absent for lists with semantically related words. The semantic facilitation effect was seen in all groups, but with a lower magnitude in the L-MTLE group, suggesting that the spread of discharges in the left hemisphere interferes with the automatic processing of semantic networks. Keywords: mesial temporal lobe epilepsy; serial position curve; semantic facilitation; episodic memory; semantic memory.