The impact of English language proficiency on neuropsychological test performance in ethnically diverse individuals

Several factors including acculturation, amount of education inside and outside the United States, age, and English fluency have been found to negatively impact performance on neuropsychological tests in ethnically diverse individuals. To our knowledge, none of these studies used a quantitative measure of English language proficiency in a multiethnic sample. The present study used a quantitative measure of English language proficiency to determine the best predictor of poor performance on neuropsychological tests. Participants were 59 individuals composed of the following ethnic groups: Hispanic, Middle Eastern and Asian/Pacific Islander. All participants were administered a neuropsychological battery containing both verbal (Controlled Oral Word Association Test (COWAT), Boston Naming Test (BNT), and the Stroop Test) and nonverbal (Wisconsin Card Sorting Test (WCST), Rey-Osterrieth Complex Figure Test (ROCF), Ruff Figural Fluency Test (RFFT), and the Color Trails Test (CTT)) subtests. Based on bivariate correlations, the following measures were included in the verbal composite: COWAT (FAS and animal naming), BNT, and Stroop Test part B, and the following measures were included in the nonverbal composite: WCST (total errors, categories completed, and percentage of conceptual-level responses), CTT-1 and 2, and Stroop C. A standard hierarchical regression was conducted to determine whether either verbal or nonverbal composite variables were related to demographic (age and total years of education) and cultural variables (acculturation, amount of education obtained outside of the U.S., and English language proficiency). It was hypothesized that 1) level of acculturation and amount of education obtained outside of the United States would impact verbal and nonverbal neuropsychological test performance above and beyond demographic factors, and 2) English language proficiency would be a stronger predictor of verbal neuropsychological test performance than the other two cultural factors. The results mostly supported the hypotheses and demonstrate the importance of quantitatively assessing English language proficiency in neuropsychological testing with ethnically diverse individuals.