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P4‐149: Neuropathology of cognitively normal elderly
Author(s) -
Farfel Jose M.,
Grinberg Lea T.,
Ferretti Renata E.L.,
Leite Renata E.P.,
Alho Ana T.L.,
Moreira Eliza G.,
Pasqualucci Carlos A.,
Saldiva Paulo H.N.,
Nitrini Ricardo,
Filho Wilson Jacob
Publication year - 2008
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2008.05.2215
Subject(s) - neuropathology , medicine , dementia , senile plaques , depression (economics) , disease , alzheimer's disease , clinical dementia rating , gerontology , psychiatry , pathology , economics , macroeconomics
Background: It has long been established that cognitively normal elderly can meet neuropathologic criteria for Alzheimer disease (AD). These cases are known as “pre-clinical AD”. However, it is a matter of debate whether there is a threshold for AD pathology to become clinically manifested. Moreover, differences in individual characteristics between normal and pre-clinical cases have not been extensively investigated. Objectives: To evaluate the burden of AD-type neuropathology on a cognitively intact sample and to investigate the variables that differentiate non-demented cases with and without disseminate brain pathology of AD. Methods: A post-mortem study evaluating 57 patients, aged 80 years or older, randomly selected from the Brain Bank of the Brazilian Aging Brain Study from University of Sao Paulo. Cognitive evaluation was gathered with a knowledgeable informant using the Clinical Dementia Scale (CDR) and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). All the cases had a CDR 0 and IQCODE 3.20. Neuropathological examinations were carried out based on accepted criteria, using immunohistochemistry. The cases were classified neuropathologically according to the Braak and Braak staging, the CERAD and the National Institute of HealthReagan Institute (NIA-RI) criteria. The case was considered “preclinical” if Braak staging IV or CERAD moderate or frequent neuritic plaques or NIA-RI criteria intermediate or high likelihood. Demographics (age, sex and education), history of cigarette smoking, alcohol abuse, hypertension, diabetes, stroke, cardiovascular disease and depression were compared among the groups. Results: A considerable percentage of subjects fulfilled one or more neuropathoogic criteria for “pre-clinical” AD. (29.8% of Braak stages IV; 31.6% of cases with moderate or frequent neuritic plaques; 19.3% of intermediate or high likelihood in the NIA-RI criteria). A higher educational level was found on the pre-clinical group according to Braak staging but not on the CERAD (2.83 years for Braak 3 and 4.94 years for Braak 4, P 0.026). Conclusions: A minimum neuropathologic threshold for clinical AD cannot be determined based on current diagnostic criteria. Cognitively normal elderly can frequently meet AD neuropathologic criteria. These individuals probably have a higher cognitive reserve in which educational level may play an important role.