Abstracts

Rationale: Patients who undergo left ATL for intractable epilepsy are at risk of postoperative memory decline. Predicting the relative risk of memory decline is difficult. This study attempts to identify the best predictors of memory after ATL using preoperative tests. Methods: Thirty-two consecutive patients who underwent left ATL with left hemisphere speech dominance and complete preoperative and 8-month postoperative neuropsychological testing were retrospectively identified. The following independent variables were analyzed by multiple regression: age of onset, etiology, gender, and intracarotid amytal procedure (IAP) results. IAP memory performance was scored using three different methods: 1) asymmetry scores (memory retention of the right hemisphere subtracted from that of the left hemisphere), 2) pass/fail classification (50 percent cut off score), and 3) pass/fail classification (67 percent cut off score). Neuropsychological measures of verbal and nonverbal memory and seizure reduction (seizure free or not) served as dependent variables. Results: The best predictors of verbal memory preservation included female gender (p?0.01) and IAP results in which memory passed with the right hemisphere and failed with the left (50 percent cut off score) (p?0.03). In contrast, male patients and those who failed memory testing with both the right and left hemispheres (50 percent cut off score) were noted to have a significant decline in verbal memory (p?0.008). Seizure freedom was predicted by high asymmetry scores (p?0.04) and IAP in which memory passed with the right hemisphere and failed with the left (67 percent cut off score) (p?0.04). Conclusion: The best predictors of verbal memory preservation after left ATL included female gender and IAP results in which memory passed with the right hemisphere and failed with the left (50 percent cut off score).