Abstracts

Rationale: Prospective Memory (PM) refers to a set of cognitive skills that allow recalling an intention in the future, in the appropriate moment, and is related to executive functions and episodic memory. A previous study suggested the role of mesial temporal structures in the prospective component of longterm prospective memory tasks. Mesial temporal lobe structures resection may differentially impact memory and executive functions. Objective: To evaluate the impact of epilepsy surgery on the prospective component of prospective memory. Methods: Six-task Prospective Memory Paradigm (three event related; three time related). Normal group (without epilepsy) and two unilateral MTS patients groups were evaluated: a surgical group (pre- and one year postoperatively) and a control test-retest group. Results: 42 subjects (without epilepsy), 20 patients of the test-retest group (retest controls) (11/20, 55% RMTS) and 39 patients of the surgical group (20/39 patients, 51% RMTS) were evaluated. Groups did not differ in demographics and IQ. 94% of surgical patients were seizure-free. Antiepileptic drug load reduction was noted in the surgical group. Improved PM performance was noted in both groups: test-retest and surgical (Subjects without epilepsy= 16,9 (+1,9); Test-retest= RMTS 1st evaluation: 12.5 (+5.8); 2nd Evaluation: 14.5 (+3.5) / LMTS 1st evaluation: 9.2 (+4.1); 2nd evaluation: 13.0 (+4.3). Surgical group= RMTS Evaluation 1: 14.4 (+3.3); Evaluation 2: 15.1 (+2.7) / LMTS Evaluation 1: 14.5 (+3.9); Evaluation 2: 15.0 (+2.2), indicative of a learning effect. A mild improvement was noted in executive functioning in the RMTS surgical group and a decline in verbal memory was noted in the left surgical MTS group. Reliable change index (RCI) analysis indicated that the surgical group did not improve performance. Conclusions: Differently from episodic memory and executive functions, the prospective component of PM remains stable after epilepsy surgery, despite decline in verbal memory for the left MTS group and mild improvement in executive functioning.