Abstracts

Rationale: Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy, a frequently occurring neurological disorder. Roughly 30 percent of patients with TLE are intractable to medication. Pre-surgical evaluation for refractory epilepsy often includes neuropsychological evaluation, as it is useful in predicting surgical outcome. Anterior temporal lobectomy (ATL) results in one-year seizure freedom in about 70 percent of individuals, but can result in post-surgical memory loss. Pre-surgical memory functioning is important in predicting post-surgical outcome function. Several measures of material specific memory are available, and have shown efficacy. The Rey Auditory Verbal Learning Task (RAVLT) and Wechsler Memory Scale - 3rd Edition (WMS-III) are common measures used to assess for material specific memory functioning. However, debate remains as to the most predictive measure. This study compared the predictive value of various verbal memory tests to predicting post-surgical outcome. Methods: The study used data collected during neuropsychological evaluation of those patients diagnosed with temporal lobe epilepsy. Participants: 38 participants met inclusion and exclusion criteria. There were 17 left TLE (LTLE) and 21 right TLE(RTLE) patients. Variables/Measures: All participants completed comprehensive neuropsychological evaluations, including the RAVLT and WMS-III. Results: There was no significant difference between right and left TLE groups in age (LTLE = 40, SD = 12.3; RTLE = 38, SD = 14.7), gender, or ethnicity (p>.05). Years of education significantly differed (LTLE = 12.4 years ed.; RTLE = 14.5), and education was used as a covariate in subsequent analyses. MANCOVA revealed LTLE patients scored significantly worse than RTLE patients on the WMS-III auditory memory indices and RAVLT short-delay to long-delay (p<.05), while there was no difference in WMS-III visual memory index scores (p>.10). Regression found the RAVLT Trial 6 and 7 and WMS-III logical memory subtests as predictors. Visual memory measures did not add to prediction of post-surgical memory outcome. Conclusions: These data support existing research that finds LTLE patients score significantly lower on measures of verbal memory. Data also suggest the RAVLT is sensitive to left TLE. RAVLT and WMS-III logical memory scores were significant predictors of outcome. Further evaluation may assist in determining if further testing beyond RAVLT or story memory is necessary. Predicting post-operative memory outcome for individuals with non-dominant TLE remains challenging.