Abstracts

Rationale: Verbal memory decline after temporal lobe epilepsy surgery is a consistent finding in many studies. We have found the variability in memory development after temporal lobe epilepsy surgery in different age groups of patients. Especially the memory of patients over forty years of age seems to be considerably impaired. In this study, we aimed to explore the possible effect of age on a post-surgical memory development.Methods: In this research, we selected two groups of patients who underwent temporal lobe epilepsy surgery: a group of 31 patients (20 M, 11 F) up to 30 years of age and a group of 17 patients (12 M, 5 F) over 45 years of age. We collected data using the Wechsler memory test. The memory was evaluated three times: before the surgery, a year after and three to five years after the surgery. MQ change exceeding standard error was considered improvement/worsening of memory. With regards to this, we split the sample into unchanged and worsened patients. Groups under 30 and over 45 years of age, both worsened and unchanged, were compared according to etiology, duration of the disease, surgery in dominant hemisphere, MRI findings, Engel s outcome and Wada test results. Results: We found memory worsening in 29% (9/31) of patients in the group under 30, compared to 41% (7/17) of patients in the group over 45. These percentages did not differ with regards to whether the surgery was done on the language dominance hemisphere or not. The MTS create the most frequent group of MRI findings (also dysplasia, DNET, low-grade glioma, vascular lesion and normal findings). In the MTS findings group, worsening was found in 16.7% (3/18) of younger and 45.5% (5/11) of older patients. Four younger and four older patients underwent an awake craniotomy with preoperative memory testing. The memory of all the patients, except an older one, did not change after surgery. The age groups did not differ with memory outcome in the cases of the AMTR and the lesionectomy. On the contrary, we found considerably less memory worsening in the younger group who underwent a selective amygdalohippocampectomy. Memory got worse in 1 patient of 7 younger (14.3%) compared to 4 worsened patients of 6 (66.6%) in the older group. We selected the patients with 1a outcome according to Engel s classification. In the first year after surgery 38% of patients in both age groups got worse; 3 years after surgery 34.8% of younger and 42.9 % of older 1a patients got worse and 5 years after surgery 30% of younger and 75% of older 1a patients got worse. Conclusions: Our results prove the expectation that the post-surgical memory of surgically treated patients aged over 45 decreases. However, the worsening is rather moderate. The memory change is more apparent with MTS etiology. Our data shows a selective amygdalohippocampectomy is more effective to prevent memory declination in younger patients. In the group above 45, the memory declines in spite of an excellent post-surgery outcome (Engel s 1a group).