Abstracts

Rationale: Prospective memory (PM) relates to cognitive skills associated with future intention recall, in the adequate timing, and it is an ecological memory measurement. Frontal lobe supported mental processes are known to play a role in PM. We evaluated the effect of lesion side on performance in a PM battery and we analyzed the correlation of performance in the PM battery with measurements of episodic memory, attention, executive functions, language, mood, depression and with a self-assessment questionnaire of memory, in patients with unilateral mesial temporal sclerosis (MTS) Methods: We evaluated patients with right (RMTS) or left (LMTS) mesial temporal sclerosis and a normal control group (C), matched for age, gender and education, with a PM test containing three time-based and three event-based activities, with and without cued recall. The battery was applied in a 105 minute session, concomitantly with formal neuropsychological testing, that included: attention and executive functions (Digit span, Stroop Test, Verbal fluency-FAS, Wisconsin Card Sorting Test - WCST), verbal and non-verbal memory (RAVLT and RCF immediate and delayed recall – 30 minutes and seven days), language (Boston naming test- BNT), a self-administered memory questionnaire (SAMQ), as well as anxiety (HAD-A) and depression (HAD-D) scales for the General Hospital. We compared performance among groups for each test with non-parametric analysis (Kruskall-Wallis), with multiple comparisons for p<0,05 and correlated performance with Spearman coefficient. Significance level was accepted at 0.05.Results: We evaluated 48 patients (26 RMTS; 22 LMTS) and 26 C, matched by age (RMTS= 37, 3 + 9,5; LMTS= 39,4 + 10,5; C =41+ 10,9), gender (RMTS 53% females, LMTS 50%, C 50% ) and education (RMTS= 11,5 + 2,2; LMTS= 11,9 + 2,3 e C= 11,4 + 2,2). Mean number of seizures in the three preceding months was similar in L and R MTS groups (RMTS= 9 + 9,3, LMTS= 12,7 + 11,5). RMTS patients were slightly more medicated than LMTS patients. L and R MTS performed significantly worse than C in PM (RMTS= 13,6 + 4,2; LMTS= 10,9 + 4,5; C= 17,0 +1,3 p<0.01). RMTS patients also performed significantly worse than LMTS (p=0.046). Performance was significantly influenced by time interval, familiarity and attention demand in both patients groups. RMTS and LMTS patients benefited less from cues than controls. In LMTS patients, PM performance was strongly correlated with delayed verbal recall (rs=0,811; p<0,01) and memory self assessment (rs=0,618; p< 0,01). Performance in PM did not correlate with executive functions or depression and anxiety measures in MTS groups. Conclusions: There is both a lesion and laterality (worse with left sided lesions) effect in PM performance in MTS patients, which is not explained by medication or executive dysfunction. PM testing can be a useful assessment of memory function in epilepsy patients. Further research will be needed to study the role of hippocampus, in remembering to remember tasks, in longer retention intervals.