Abstracts

Standardized measures of verbal and nonverbal memory have frequently failed to differentiate dominant from nondominant temporal lobe epilepsy patients, even following surgical resection of the mesial temporal structures. While recent published studies have emphasized the importance of multiple trial learning paradigms for these comparisons, there is little agreement on which measures are most valid, particularly for the assessment of nonverbal learning in this population. The current study updates our experience with verbal and nonverbal selective reminding paradigms in assessing verbal and visual learning and retention in temporal lobectomy patients before and after surgery., Sixty-six temporal lobectomy candidates (32 left, 34 right) were evaluated pre and postoperatively using the Verbal Selective Reminding Test (VSRT) of Buschke and the Nonverbal Selective Reminding Test (NVSRT) of Fletcher. Fifty-two patients were left hemisphere dominant based on the Intracarotid Amobarbital Procedure (IAP), while 12 demonstrated some degree of bilateral language representation. Three patients could not be classified. All patients underwent temporal lobectomy including resection of the mesial temporal structures. There were no differences between the left and right groups in age at surgery, IQ, or gender distribution. Performance of the left and right temporal groups were compared on learning and retention scores using t-tests for independent samples., Left temporal (LT) patients were mildly impaired on learning and recall measures of the VSRT preoperatively compared to right temporal (RT) patients who performed in the average range (p[lt] .01) Postoperatively, performance of the LT group declined to the moderately impaired range, while the RT group performance remained stable. On the NVSRT, the RT group performed in the low average range preoperatively, significantly below the LT group on one learning measure (p [lt].05), while the LT performance was in the normal range pre and postoperatively on the learning measures. Delayed recall scores showed a decline from mildly impaired preoperatively to clearly impaired postoperatively for the RT group, while LT performance was mildly impaired at baseline, but remained stable following surgery. Differences between the two groups were statistically significant (p [lt].03)., Selective reminding paradigms are sensitive to verbal and visual memory impairment and may be helpful in discriminating dominant from nondominant temporal lobe dysfunction in epilepsy patients undergoing initial evaluation. Striking postoperative group differences underscore the material specific nature of memory processing in the two hemispheres and the importance of preoperative counseling prior to surgery.,