Memory Decline Following Epilepsy Surgery: Can We Predict Who Will Pay the Price?

Postoperative Memory Prognosis in Temporal Lobe Epilepsy Surgery: The Contribution of Postictal Memory Sveikata L, Kavan N, Pegna AJ, et al. Epilepsia. 2019;60(8):1639-1649. doi:10.1111/epi.16281. Epub July 22, 2019. PMID: 31329286. Objective: The prediction of verbal memory decline after temporal lobe epilepsy (TLE) surgery remains difficult at an individual level. We evaluated the prognostic value of postictal memory testing in predicting the postoperative verbal memory function. Methods: Sixty-three consecutive patients were included in the analysis who underwent TLE surgery at our center with preoperative interictal/postictal and postoperative memory testing. Verbal memory was evaluated using the Rey Auditory Verbal Learning Test (RAVLT). We used reliable change indices with 90% confidence interval (90% RCIs) to evaluate a significant postoperative memory decline. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), area under the curve (AUC), and accuracy (ACC) were calculated. The analysis was performed for all patients with TLE and for the subgroup with hippocampal sclerosis (HS). Results: Patients with left TLE (n = 31) had lower verbal memory scores on RAVLT than right TLE at 3 months (57% vs 78%) and 12 months (53% vs 78%) after surgery. The 90% RCI was estimated to be a loss of 4 out of 15 items. The predictive value was Sn = 42%, Sp = 84%, PPV = 39%, NPV = 86%, AUC = 0.630, and ACC = 76% to predict a verbal memory decline in the whole group (n = 63). In patients with HS (n = 41), the postictal verbal memory test had Sn = 50%, Sp = 88%, PPV = 50%, NPV = 88%, AUC = 0.689, and ACC = 81% to predict a significant postoperative decline. Significance: Postictal memory is a noninvasive bedside memory test that can help predict the postoperative verbal memory decline in patients with HS with an overall ACC of 81%.