Association of Apolipoprotein E-e4 and Dementia Declines with Age

To study the association of dementia with apolipoprotein E-e4 (APOE-e4) and its interaction with age in a nonagenarian Costa Rican group (N-sample) and a general elderly contrast group (GE-sample). In both case-control studies, participants were cognitively intact or diagnosed with dementia. The N-sample (N = 112) was at least age 90 years; the GE-sample (N = 98) was at least age 65 years. Dementia and APOE-e4 were not significantly associated in the N-sample, but were in the GE-sample. There was a significant interaction of age with APOE-e4 in the N-sample, but not in the GE-sample. Descriptively dividing the N-sample at the median (age 93 years) showed a group interaction: APOE-e4 was more associated with dementia in the younger N-sample than in the older N-sample, where six of seven APOE-e4 carriers were cognitively intact. The results support the reduction in association of APOE-e4 with dementia in extreme old age, consistent with a survivor effect model for successful cognitive aging.Universidad de Costa Rica/[]/UCR/Costa RicaFogarty International Center/[]/NIH/Estados UnidosNational Institute on Aging/[R21TW009258]/NIH/Estados UnidosAlzheimer’s Association/[]//Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Centro de Investigación en Neurociencias (CIN)UCR::Vicerrectoría de Docencia::Salud::Facultad de Medicina::Escuela de MedicinaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Neuropsychological Test Performance in Cognitively Normal Spanish-speaking Nonagenarians with Little Education

To find associations of age, sex, and education with neuropsychological test performance in cognitively normal Spanish-speaking Costa Rican nonagenarians with little education; to provide norms; and to compare their performance with similar Puerto Ricans. For 95 Costa Ricans (90–102 years old, 0–6 years of education), multiple regression assessed associations with demographics of performance on six neuropsychological tests. Analyses of covariance compared them with 23 Puerto Ricans (90–99 years old). Younger age and being female—but not education—were associated with better performance on some neuropsychological tests, in particular episodic memory. The Puerto Ricans performed better on learning and memory tasks. In cognitively intact Spanish-speaking nonagenarians with little or no education, education did not affect test performance. Additional studies of the effect of education on cognitive performance are warranted in other samples with extremely low education or old age. National differences in performance highlight the importance of group-specific norms.National Institutes of Health/[R21TW009258]/NIH/Estados UnidosUniversidad de Costa Rica/[]/UCR/Costa RicaAlzheimer’s Association/[]//Estados UnidosUCR::Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí

Heritability of Cognitive Functions in Families of Successful Cognitive Aging Probands from the Central Valley of Costa Rica

artículo (arbitrado) -- Universidad de Costa Rica. Centro de Investigación en Biología Celular y Molecular. Escuela de Biología, 2011We sought to identify cognitive phenotypes for family/genetic studies of successful cognitive aging (SCA; maintaining intact cognitive functioning while living to late old age).We administered a battery of neuropsychological tests to nondemented nonagenarians (n = 65; mean age = 93.4±3.0) and their offspring (n = 188; mean age = 66.4±5.0) from the Central Valley of Costa Rica. After covarying for age, gender, and years of education, as necessary, heritability was calculated for cognitive functions at three pre-defined levels of complexity: specific neuropsychological functions (e.g., delayed recall, sequencing), three higher level cognitive domains (memory, executive functions, attention), and an overall neuropsychological summary. The highest heritability was for delayed recall (h2 = 0.74, se = 0.14, p < 0.0001) but significant heritabilities involving memory were also observed for immediate recall (h2 = 0.50), memory as a cognitive domain (h2 = 0.53), and the overall neuropsychological summary (h2 = 0.42). Heritabilities for sequencing (h2 = 0.42), fluency (h2 = 0.39), abstraction (h2 = 0.36), and the executive functions cognitive domain (h2 = 0.35) were also significant. In contrast, the attention domain and memory recognition were not significantly heritable in these families. Among the heritable specific cognitive functions, a strong pleiotropic effect (i.e., evidence that these may be influenced by the same gene or set of genes) for delayed and immediate recall was identified (bivariate statistic = 0.934, p < 0.0001) and more modest but significant effects were found for four additional bivariate relationships. The results support the heritability of good cognitive function in old age and the utilization of several levels of phenotypes, and they suggest that several measures involving memory may be especially useful for family/genetic studies of SCA.Universidad de Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM