In vivo imaging evidence of poor cognitive resilience to Alzheimer's disease pathology in subjects with very low cognitive reserve from a low‐middle income environment

Abstract

INTRODUCTION: Reduced cognitive reserve (CR) due to very low educational (VLE) levels may influence high dementia rates in low‐middle income environments, leading to decreased cognitive resilience (RES) to Alzheimer´s disease (AD) pathology. However, in vivo findings in VLE groups confirming this prediction are lacking. METHODS: Cognitively impaired patients (with clinically defined AD dementia or amnestic mild cognitive impairment) and cognitively unimpaired older adults (n = 126) were recruited for a positron emission tomography (PET) and magnetic resonance imaging (MRI) investigation in Brazil, including 37 VLE individuals (≤5 years of education). A CR score was generated combining educational attainment and vocabulary knowledge. RES indices to AD pathology were calculated using standardized residuals from linear regression models relating current cognitive performance (episodic memory or overall cognition) to amyloid beta (Aβ) burden Pittsburgh compound‐B ([11C]PiB‐PET). RESULTS: Aβ burden was lower in VLE relative to highly‐educated subjects (controlling for age, sex, and Mini‐Mental Status Exam [MMSE] scores) in the overall cognitively impaired sample, and in dementia subjects when the three clinically defined groups were evaluated separately. In bivariate regression analyses for the overall sample, the RES index based on a composite cognitive score was predicted by CR, socioeconomic status, and hippocampal volume (but not white matter hyperintensities or intracranial volume [ICV]); in the multivariate model, only CR retained significance (and similar results were obtained in the Aβ‐positive subsample). In the multivariate model for the overall sample using the RES index based on memory performance, CR, hippocampal volume, and ICV were significant predictors, whereas only CR retained significance in Aβ‐positive subjects. DISCUSSION: Lower CR consistently predicted less resilience to AD pathology in older adults from a low‐middle income environment.

A profile of brain reserve in adults at genetic risk of Alzheimer's disease

“…As expected, neuropsychological scores were affected by CDR after controlling for APOE status, age, and sex, with reduced scores on the MMSE (F(1,725) = 89.4, P < 0.001) in cognitively impaired participants (Table 1). The CDR‐0 group completed more years of education compared to the CDR‐0.5 group (F = 7.2, P = 0.007) , consistent with previous studies showing that educational attainment enhances cognitive reserve 61,62 and low attainment predicts cognitive decline 63 …”

“…The CDR-0 group completed more years of education compared to the CDR-0.5 group (F = 7.2, P = 0.007), consistent with previous studies showing that educational attainment enhances cognitive reserve 61,62 and low attainment predicts cognitive decline. 63…”

Revisión sistemática sobre la influencia de la reserva cognitiva en la demencia y en la eficacia de la terapia de estimulación cognitiva

“…En relación al primero objetivo (conocer la influencia de la RC sobre los trastornos neurocognitivos, tanto como factor protector como moderador de la gravedad de la sintomatología), en el estudio de Busatto et al (2020), se tomó una muestra en ambientes desfavorecidos para conocer la interacción entre el nivel educacional, y el deterioro cognitivo. Se crearon 3 grupos: uno sin problemas cognitivos, otro diagnosticados de EA y el último…”

“…Tal y como se he comentado, la escolaridad y ocupación laboral son dos de los factores de la RC que más implicación tienen en los trastornos neurocognitivos (Farfel et al, 2013;Lojo-Seoane et al, 2012;van Loenhoud et al, 2019), donde los estudios muestran que poseer un bajo nivel de vocabulario, escolaridad y complejidad laboral es un importante factor de riesgo para el desarrollo de trastornos neurocognitivos y depresivos (Cuart Sintes, 2017;Farfel et al, 2013;Lojo-Seoana et al, 2012;van Loenhoud et al, 2019). Aunque los estudios no muestran evidencias significativas sobre la influencia de estos factores con el padecimiento de las demencias (Capogna et al, 2019;Yasuno et al, 2020), sí pone de manifiesto en relación con estos factores, que aquellas personas con una baja RC son las que peor rendimiento cognitivo mostraron en las evaluaciones (Busatto et al, 2020;Contador et al, 2017;Darwish et al, 2018;Haussmann et al, 2020;Sobral et al, 2015). Concretamente, las personas con una menor escolaridad son aquellas que tienen una mayor probabilidad de padecer un trastorno neurocognitivo en el futuro (Busatto et al, 2020;Contador et al, 2017).…”

Clinical Impact of PET With 18F-FDG and 11C-PIB in Patients With Dementia in a Developing Country

“…Even though only nine countries in the LAC region have cyclotrons for the production of radiotracers, the access to PET in the region has improved in the last few years, with an annual growth of ∼21% (7,8). Access to amyloid tracers has also improved and the proposed A-T-N criteria are increasingly being applied to classify the patients in research studies (19,20,(39)(40)(41)(42)(43)(44). Regarding the clinical utility of amyloid PET, Chrem Mendez et al described 76.2% concordance of 11 C-PIB PET with baseline diagnosis in patients with AD, and a range of concordance of 54.5-100% in other forms of cognitive impairment (19).…”