Bilingualism in the Clinical Diagnosis of Mild Cognitive Impairment and Dementia

Abstract

AbstractBackgroundNeuropsychological assessments determine the presence of cognitive impairment in Alzheimer’s Disease and Related Dementias (ADRD). These tests are susceptible to the influence of cultural and linguistic variables. Bilingualism is a potential contributor to cognitive reserve in elderly individuals. Positive effects of bilingualism have been observed in executive function tasks, while negative effects have been reported on verbal fluency tests. Maintaining two active languages may modify cognitive and brain reserve among bilinguals, but evidence is inconsistent and contradictory. We investigated the relationship between bilingualism and neuropsychological test performance in aging participants from the 1Florida ADRC using a longitudinal design.MethodsWe studied 238 Latino older adults (age 71.79 ± 8.01 years old, 65% female). 158 Latino participants were Spanish‐English bilinguals; 80 were Spanish monolinguals. Bilingualism was assessed by a proficiency questionnaire. Six cognitive composites were developed (Figure 1). We investigated cognitive test change scores between language group, visit (2 visits: M = 14.61 months; SD = 3.52), and diagnosis (normal, MCI, dementia) using 2×2×3 repeated measures ANCOVAs (age and level of education). Cognitive scores were correlated with frontal and temporal brain volumes in bilinguals and monolinguals separately.ResultsMain effects of the diagnostic group and visit were significant for all composites (ps < .001), with the dementia group showing the lowest scores. No significant main effect of Bilingualism was observed for any of the composites. An interaction between visit and bilingualism was seen for the Trail Making Test B‐ A. Three‐way interactions were found between diagnostic groups, visit, and bilingualism for the Verbal composite and the Logical Memory delay subtest (part of the Memory composite). A more significant decline in the monolingual groups was observed, more so in the dementia group. Significant correlations were found between most composites in both language groups, being more related to the temporal than frontal lobe areas, using MRI volumetric measures.ConclusionBilingualism seems to interact with cognitive decline in aging. It is essential to consider the individual’s level of bilingualism to obtain an accurate assessment of cognitive impairment. The interaction of bilingualism with other sociodemographic and cognitive variables will be discussed.