Ten-year cognitive outcomes following epilepsy surgery: Temporal lobectomy versus selective amygdalohippocampectomy

This study aimed to assess long-term memory outcomes in patients with temporal lobe epilepsy (TLE) who underwent anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH), compared to nonoperated TLE over a 10-year follow-up period.

A total of 48 participants were studied: 10 ATL, 26 SAH, and 12 patients with nonoperated mesial temporal lobe epilepsy (MTLE). Verbal memory was assessed using the Sözel Bellek Süreçleri Testi (SBST-a test of verbal memory processes), and nonverbal memory was evaluated with the Wechsler memory scale-visual reproduction (WMS) (Turkish adaptation). Given the small and unbalanced groups, linear mixed-effects models (LMMs) were used as the primary inferential analyses to test group × time interactions. Statistically reliable individual changes were identified using the reliable change index (RCI). Neuropsychological outcomes were analyzed longitudinally over a 10-year follow-up period.

A significant group × time interaction was observed for verbal total learning (p = 0.001). The nonoperated TLE group showed a significant decline over time, whereas both surgical groups differed significantly from it. The ATL group demonstrated significant improvement. For delayed verbal recall, a significant main effect of group was observed; however, the group × time interaction was not statistically significant. Visual immediate recall showed a significant group × time interaction (p = 0.004), with a significant interaction effect in the ATL group. Visual delayed recall demonstrated a significant group × time interaction (p < 0.001), with significant interaction effects in both surgical groups. Seizure freedom was achieved in 90% of ATL and 80% of SAH cases; however, seizure outcome was not significantly associated with memory outcomes. Reliable change index analyses indicated lateralization-dependent patterns of change.

ATL, particularly left-sided ATL, was associated with statistically significant long-term improvements in verbal memory and significant longitudinal changes in visual memory. SAH demonstrated significant longitudinal effects in selected memory domains. In contrast, nonoperated TLE patients showed significant cognitive decline over time. These findings highlight differential long-term cognitive trajectories across treatment approaches and the role of lateralization in memory outcomes following epilepsy surgery.

We examined memory changes over 10 years in people with temporal lobe epilepsy who underwent different surgical treatments or received medical management alone. Patients who underwent anterior temporal lobectomy (ATL), particularly on the left side, showed improvement in certain memory measures over time. Those who had selective amygdalohippocampectomy (SAH) demonstrated more domain-specific cognitive changes despite good seizure control. In contrast, patients who did not undergo surgery experienced a decline in verbal learning. These findings suggest that surgical approach and brain lateralization play important roles in long-term memory outcomes.