Clinical Neuropsychology of Bilingual Mexican American Adults: Effect of Language Proficiency and Dominance.

This article investigates the relationship between language proficiency and neuropsychological test performance in Spanish-English bilingual Mexican American adults, focusing on language-formatted versus visual-perceptual formatted and executive versus delayed memory measures. Using the Woodcock–Muñoz Language Survey—Revised (WMLS-R) to objectively assess language proficiency and dominance, the study found that language proficiency positively correlates with performance on language-formatted neuropsychological tests but not on visual-perceptual formatted measures. Absolute language dominance showed no significant association with any neuropsychological scores, providing no support for a bilingual advantage in executive function within this sample. The findings suggest that monolingual neuropsychological test norms may overestimate bilingual Mexican Americans' abilities on language-based tests, highlighting the importance of using objective language proficiency measures to better estimate preexisting skill levels in neuropsychological assessments of bilingual individuals.