Clinicopathological correlates of Alzheimer’s disease in a general autopsy series from Brazil

The current neuropathological staging models of Alzheimer's disease (AD) have been developed within the last 20 years. Nevertheless, they were mostly tested on Caucasians of Northern European ancestry or on Asians. Objective To verify which of the accepted neuropathologic criteria best discriminates AD from normal aging in a well characterized Brazilian clinicopathological series. Methods A random sample consisting of 89 subjects belonging to the Brazilian Brain Bank of the Aging Brain Study were clinically and neuropathologically fully assessed using immunohistochemistry. Clinical and functional statuses were assessed by interviewing a reliable informant. The Clinical dementia rating scale (CDR) was compared to Braak and Braak stage, the consortium to establish a registry for Alzheimer's disease (CERAD) score and NIA-Reagan (National Institute of Aging - Reagan Institute) score. Subjects with a neuropathologic diagnosis other then AD were excluded (n=27). Results The CDR score distribution for the 62 selected subjects was as follows: CDR0=39, CDR0.5=9, CDR1=14. There were no differences regarding age, gender and education among the groups. CDR score correlated best with the CERAD score (r=0.5303; p<0.001) . Braak and Braak stage was significantly higher in subjects with higher CDR. Correlation of the NIA-Reagan criteria was partially disrupted because a large proportion of subjects did not fit any of its categories. Conclusions In this series, CERAD criteria better correlated with the CDR groups. Consistent with earlier studies, some cognitively normal subjects have AD neuropathological diagnosis.