Abstracts

Rationale: Neuropsychological testing assists in lateralization of seizure focus in presurgical workup of English-speaking medically intractable epilepsy (IE) patients. However, studies on a Spanish-speaker battery, Neuropsychological Screening Battery for Hispanics (NeSBHis), are limited and have shown differing results on lateralization ability (Barr et al 2009; Lancman et al 2012). These studies did not account for educational differences, but Pontón et al (1996) demonstrated the influence of educational level (Ed) on NeSBHIS scores. We postulated that Ed differences may suppress the NeSBHIS' lateralizing properties and that Ed effects would hold in a unique, southwestern USA, Hispanic Spanish-speaking sample of IE patients. Methods: Retrospective analysis was conducted on 76 Spanish speaking subjects undergoing presurgical video-EEG telemetry and neuropsychological evaluation including NeSHBIS. Subjects were classified into Low Education (LE) (≤ 6 yrs schooling, n=33) or High Education (HE) (> 6 yrs, n=43), and Left (LH, n=25) or Right Hemisphere (RH, n=27) seizure onset. Bilateral or inconclusive seizure lateralization was excluded from lateralization analyses. Comparisons of NeSHBIS scores and seizure lateralization between LE and HE were made with t-tests. Results: Mean age was 35.9±10.1, median epilepsy onset age was 9 years, and mean education was 8.1±3.5 years. There were no significant differences in age, gender, seizure lateralization, or epilepsy duration between LE vs HE. LE subjects performed significantly worse than HE on Ravens Progressive Matrices, p <.001; Block Design, p = .02; Digit Symbol, p < .001; Digit Span, p = .004; Modified Boston Naming Test, p < .001; Controlled Oral Word Association Test, p =.006; Color Trails 1, p = .002; Color Trails 2, p = .009; Rey Complex Figure (RCFT) Copy, p = .007; RCFT Delay, p = .045; WHO AVLT 1, p = .006; WHO AVLT 5, p = .031; and WHO AVLT 8, p = .013. When all subjects were analyzed, no differences were seen between LH and RH onset patient scores. LH and RH did not differ in education years, p = .22. In subgroup analysis, LE subjects still yielded no significant differences in LH vs RH-onset, but the HE group showed significant differences on the WHO UCLA AVLT Trial 5, wherein LH-onset patients learned fewer words than RH-onset patients after the fifth exposure to the word list, p=.048. Conclusions: Our results illustrate a robust effect of education level on neuropsychological scores of Spanish speakers with IE. Similar to Barr et al, the NeSBHIS did not predict seizure lateralization in our sample. However, when divided by education group, word list recall accurately predicted seizure lateralization in those with greater than primary school education, while the NeSBHIS remained unpredictive in patients with ≤6 years schooling. This study suggests that the NeSBHIS' ability to lateralize seizure onset could be improved by accounting for educational level and that future studies should include education considerations.