Project Summary
Estimates from the Alzheimer's Association indicate that approximately one in ten older adults in the US have
Alzheimer's disease (AD) while 15 to 20% have mild cognitive impairment (MCI), projecting that about a third
of those will develop dementia within five years. Several variables have been associated with delaying the
onset and rate of cognitive decline in AD and have been grouped under the Cognitive Reserve/ Resilience
(CR/R) theory; it postulates that complex mental activity throughout the lifetime creates resistance to cognitive
decline despite the biological risk (brain loss). Emerging evidence shows that bilingualism may be one of these
neuroprotective factors in the aging brain, but results in bilingualism and CR/R remain inconsistent. Our
objective is to analyze the contribution of bilingualism to CR/R in a large cohort of aging Spanish/English
bilinguals and Spanish monolinguals with amnestic MCI (aMCI). To overcome limitations in previous research,
we will use a longitudinal design, operational characterization of bilingualism, refined sociocultural measures,
and multimodal neuroimaging. The current study will leverage and extend a large ongoing NIH cohort
prospective study from the 1Florida Alzheimer's Disease Research Center (1Florida ADRC), in which
Spanish/English bilingual Hispanics with aMCI are well-represented (n = 120), but Spanish monolinguals are
underrepresented although they comprise approximately 40% of foreign-born Hispanics in the US. In the
present study, we directly address this by deploying an intensive, culturally-informed, community-engaged
research approach in the Miami area to increase outreach and recruit 120 Hispanic monolinguals with aMCI.
We will make the ADRC MCI bilingual and monolingual groups ethnically equivalent and create a longitudinal
data set (n=240), ensuring that we are well-powered to determine the contribution of bilingualism to CR in the
aMCI population. As co-investigators on the 1Florida ADRC, our research team is well-positioned to execute
the proposed study. We will collect neuropsychological data at years 1, 2, and 3 and neuroimaging data (MRI
and DTI) at years 1 and 3. The neuropsychological battery will include the Loewenstein-Acevedo Scale for
Semantic Interference and Learning (LASSI-L), a cognitive stress test that evaluates failure to recover from
Proactive Semantic Interference (frPSI) and is highly sensitive to subtle cognitive changes in early AD. The
innovation lies in studying the relationship between brain diffusivity measures of WM and frPSI, as measured
by the LASSI-L in combination with volumetric brain data; the use of Bilingual indexes of language proficiency
and degrees of acculturation, and levels of education. Our findings will advance our understanding of the
complex interactions between neural, environmental, and sociocultural factors and the role of bilingualism in
CR/R in AD/ADRD, paving the way for new targets for interventions and providing fundamental insight into the
role of language(s) in the aging brain.