Abstracts

RATIONALE: Assessment of memory function is an important part of comprehensive evaluation of patients with Temporal Lobe Epilepsy (TLE) who are surgical candidates. While there are many memory tests available for English-speakers, the resources are much more limited when assessing Spanish-speakers, both in terms of appropriate tests and research to support the utility of such measures. Common neuropsychological measures have been translated into Spanish and a few tests have been specifically developed for use with Spanish-speakers, although there is little, if any, literature to guide memory assessment in epilepsy in this population. The current study examined the utility of two different verbal memory measures in Spanish-speaking right and left TLE patients.
METHODS: Eighteen Spanish-speaking surgical candidates with Right (n=7) or Left (n=11) TLE underwent neuropsychological assessment as part of a neurodiagnostic work-up of their seizure disorder. All were administered a Spanish translation of the Logical Memory (LM) subtest from the Wechsler Memory Scale - Revised/3rd edition (story memory test translated into Spanish), and the Spanish Verbal Learning Test (SVLT, Harris et al., 1995), a 16-item list-learning task developed for use with Spanish-speakers. Right and Left TLE patients were of similar age (34 vs 36 years) and education (7.8 vs 7 years), and all patients reported Spanish as their primary or only language. Duration of epilepsy was also similar between groups (23.5 vs 22.8 years).
RESULTS: Significant differences were observed between the Right and Left TLE groups on several SVLT scores, including Total Learning (F=6.22, p=.022), Delayed Recall (F=4.72, p=.045), and Words Learned on the 5th learning trial (F=11.01, p=.004), with the Left TLE group performing more poorly. In contrast, no significant differences were seen for SVLT percent retention of learned information or on any of the LM variables (immediate & delayed recall, % retention). In comparison with normative data, SVLT Total Recall for Right TLE patients was in the average range (T score = 47), while Left TLE subjects demonstrated mild to moderate impairment (T score = 34), indicating a more than one standard deviation discrepancy in overall learning between the groups. Performance on LM was equally poor across groups, with both groups performing more than one standard deviation below the mean using English norms.
CONCLUSIONS: Despite the difficulties in assessing Spanish-speaking individuals given the paucity of standardized measures and appropriate norms, this study supports the utility of memory assessment in evaluation of lateralized TLE. The greater sensitivity of the SVLT compared to LM in identifying lateralized memory deficits in this sample suggests that using tests specifically developed for use with Spanish-speakers may be of greater utility than conventional measures that have been translated. Therefore, neuropsychological assessment of Spanish-speaking TLE patients will be enhanced by the use of tests developed and normed for use with Spanish-Speakers and inclusion of the SVLT as a measure of verbal memory in such evaluations is recommended.