The high percentage of non- demented subjects and the ethnic diversity of this series may be significantly contributive toward aging brain processes and related neurodegenerative diseases understanding since BBBABSG outcomes may provide investigators the answers to some additional questions.

The diagnosis of normal cognition or dementia in the Brazilian Brain Bank of the Aging Brain Study Group (BBBABSG) has relied on postmortem interview with an informant.ObjectivesTo ascertain the sensitivity and specificity of postmortem diagnosis based on informant interview compared against the diagnosis established at a memory clinic.MethodsA prospective study was conducted at the BBBABSG and at the Reference Center for Cognitive Disorders (RCCD), a specialized memory clinic of the Hospital das Clínicas, University of São Paulo Medical School. Control subjects and cognitively impaired subjects were referred from the Hospital das Clínicas to the RCCD where subjects and their informants were assessed. The same informant was then interviewed at the BBBABSG. Specialists’ panel consensus, in each group, determined the final diagnosis of the case, blind to other center’s diagnosis. Data was compared for frequency of diagnostic equivalence. For this study, the diagnosis established at the RCCD was accepted as the gold standard. Sensitivity and specificity were computed.ResultsNinety individuals were included, 45 with dementia and 45 without dementia (26 cognitively normal and 19 cognitively impaired but non-demented). The informant interview at the BBBABSG had a sensitivity of 86.6% and specificity of 84.4% for the diagnosis of dementia, and a sensitivity of 65.3% and specificity of 93.7% for the diagnosis of normal cognition.ConclusionsThe informant interview used at the BBBABSG has a high specificity and sensitivity for the diagnosis of dementia as well as a high specificity for the diagnosis of normal cognition.

Previous studies in dementia epidemiology have reported higher Alzheimer's disease rates in African-Americans when compared with White Americans. To determine whether genetically determined African ancestry is associated with neuropathological changes commonly associated with dementia, we analyzed a population-based brain bank in the highly admixed city of São Paulo, Brazil. African ancestry was estimated through the use of previously described ancestry-informative markers. Risk of presence of neuritic plaques, neurofibrillary tangles, small vessel disease, brain infarcts and Lewy bodies in subjects with significant African ancestry versus those without was determined. Results were adjusted for multiple environmental risk factors, demographic variables and apolipoprotein E genotype. African ancestry was inversely correlated with neuritic plaques (P=0.03). Subjects with significant African ancestry (n=112, 55.4%) showed lower prevalence of neuritic plaques in the univariate analysis (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.55–0.95, P=0.01) and when adjusted for age, sex, APOE genotype and environmental risk factors (OR 0.43, 95% CI 0.21–0.89, P=0.02). There were no significant differences for the presence of other neuropathological alterations. We show for the first time, using genetically determined ancestry, that African ancestry may be highly protective of Alzheimer's disease neuropathology, functioning through either genetic variants or unknown environmental factors. Epidemiological studies correlating African-American race/ethnicity with increased Alzheimer's disease rates should not be interpreted as surrogates of genetic ancestry or considered to represent African-derived populations from the developing nations such as Brazil.

ObjectiveTo develop an informant-based instrument that would provide a valid estimate of premorbid cognitive abilities in low-educated populations.MethodsA questionnaire was drafted by focusing on the premorbid period with a 10-year time frame. The initial pool of items was submitted to classical test theory and a factorial analysis. The resulting instrument, named the Premorbid Cognitive Abilities Scale (PCAS), is composed of questions addressing educational attainment, major lifetime occupation, reading abilities, reading habits, writing abilities, calculation abilities, use of widely available technology, and the ability to search for specific information. The validation sample was composed of 132 older Brazilian adults from the following three demographically matched groups: normal cognitive aging (n = 72), mild cognitive impairment (n = 33), and mild dementia (n = 27). The scores of a reading test and a neuropsychological battery were adopted as construct criteria. Post-mortem inter-informant reliability was tested in a sub-study with two relatives from each deceased individual.ResultsAll items presented good discriminative power, with corrected item-total correlation varying from 0.35 to 0.74. The summed score of the instrument presented high correlation coefficients with global cognitive function (r = 0.73) and reading skills (r = 0.82). Cronbach's alpha was 0.90, showing optimal internal consistency without redundancy. The scores did not decrease across the progressive levels of cognitive impairment, suggesting that the goal of evaluating the premorbid state was achieved. The intraclass correlation coefficient was 0.96, indicating excellent inter-informant reliability.ConclusionThe instrument developed in this study has shown good properties and can be used as a valid estimate of premorbid cognitive abilities in low-educated populations. The applicability of the PCAS, both as an estimate of premorbid intelligence and cognitive reserve, is discussed.

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The present study aimed to establish the morphometric brain changes during aging in a necropsy series from Brazil and determine whether sexual dimorphisms interfere in these changes.MethodsA cross-sectional study was conducted at the São Paulo Autopsy Service in Brazil where, after informed consent, data was gathered from next of kin interview with reference to clinical status prior to death. Brain weight, volume and density measurements were taken and then adjusted for head circumference. Descriptive statistics and tests of hypothesis and correlations were applied, considering a p-value of 0.05.Results414 subjects, mostly men (60.4%), with a mean age of 67.1 years, were included. The mean brain weight of the sample was 1219.2g±140.9and mean volume was 1217mL±152.3. The mean brain density of the sample was 1.0g/mL±0.09. Values differed between males and females in terms of weight and volume. Brain weight decreased during aging by about 45g per decade (r= –0.300; p<0.01) and volume by about 43mL (r= –0.278; p<0.00). Mean density of the sample was 1.0 g/mL in both genders.ConclusionsBrain weight and volume (with or without corrections) decreased during aging, and these reductions were more pronounced in women. Density remained unchanged for both genders. Further studies are needed to investigate factors associated to these reductions.

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DEDICATÓRIA AGRADECIMENTOSAgradeço especialmente a todas as famílias que voluntariamente aceitaram em participar deste estudo e seus familiares, pela doação do tecido para fins de pesquisa. Agradeço pelo desprendimento e espírito de cooperação com causas maiores.A toda equipe do Serviço de Verificação de Óbitos da Capital, funcionários técnicos, administrativos e médicos patologistas, que contribuíram para esse trabalho, colaborando com a criação de ambiência para pesquisa. Um agradecimento especial ao Prof o Dr Carlos Augusto Pasqualucci, diretor do serviço. A toda a equipe do Banco de Encéfalos do Grupo de Estudos em Envelhecimento Cerebral da Faculdade de Medicina da Universidade de SãoPaulo, por todo o árduo trabalho para a garantia de uma estrutura sólida.A Lea Tenenholz Grinberg pelo apoio, amizade, parceria e dedicação na execução de todos os procedimentos relacionados ao BEEHGEEC, e também ao José Marcelo Farfel e Renata Leite, também meus colegas de trabalho.A minha equipe de entrevista clínica do BEHGEEC da FMUSP, que realiza a coleta dos dados clínicos com as famílias. Agradeço a vocês, Érika, Eliza, Carmo e Antônio pela dedicação ao projeto, apoio, amizade e tolerância nos momentos difíceis. submetidos à avaliação clínica completa e à análise morfométrica crânio-encefálica (perímetro cefálico, peso, volume e densidade encefálicos). As correlações entre as alterações morfométricas cerebrais e os fatores associados (variáveis sócio -demográficas e clínicas) foram obtidos por meio de análise uni e multivariadas. RESULTADOS: Amostra composta por 39,6% de mulheres e 60,4% de homens, com idade média de 68,5 (± 11,9 DP) e 66,2 (± 10,2 DP), respectivamente; maioria branca. Foi observada redução do perímetro cefálico com a idade, significante entre as mulheres, e associação discreta entre os homens. Peso e volume encefálicos diminuem com a idade. O peso médio do encéfalo da amostra toda foi de 1219,2 g (± 140,9 DP), e o volume médio foi de 1217,1 mL (± 152,3 DP). Homens apresentaram valores maiores de peso e volume encefálicos, e a redução foi mais pronunciada entre as mulheres. A densidade encefálica não se alterou em função da idade. Houve redução nos valores totais e corrigidos de peso e volume encefálicos, em algumas condições clínicas, mas apenas algumas se mostraram associadas com as reduções de peso e volume de acordo com a análise multivariada. A escolaridade se mostrou um fator protetor contra a redução de peso e volume encefálicos. CONCLUSÕES: Observouse que existem alterações morfométricas cerebrais no envelhecimento normal e, dentre os fatores associados a essas alterações, a maioria esta relacionada com o estilo de vida. Estes resultados permitem demonstrar que hábitos adequados devem ser implementados ao longo da vida visando o envelhecimento saudável. Descritores INTRODUCTION:Previous studies have led to the consensus that there are changes in brain morphology during aging, that go beyond brain atrophy. One important aspect to understand is wether there are morfometric brain changes in subject...