Mixed Brain Pathologies in Dementia: The BrainNet Europe Consortium Experience

Background: Dementia results from heterogeneous diseases of the
brain. Mixed disease forms are increasingly recognized. Methods: We
performed a survey within brain banks of BrainNet Europe to
estimate the proportion of mixed disease forms underlying dementia
and age- and gender-specific influences. Results: Data collected in
9 centres from 3,303 individuals were analysed. The proportion of
patients with mixed diagnoses among all cases with Alzheimer
disease (AD), vascular pathology (VP), argyrophilic grain dementia
(AGD), and synucleinopathies, such as Lewy body dementia (LBD),
Parkinson disease (PD) and synuclein pathology only in the
amygdala, was 53.3%. Mixed pathology was more frequently reported
with LBD, PD, AGD, and VP than with AD. The percentage of mixed
diagnoses for AGD and VP significantly differed between centres. In
patients younger than 75 years, synucleinopathies, and pure forms
of AD, VP, and AGD were more frequent in men. Above 75 years of
age, more women had pure AD and pure AGD. Conclusions: The most
obvious neuropathological alteration should not terminate the
diagnostic procedure since copathology is likely to be found.
Neuropathological interpretation of AGD and VP has not been
sufficiently established in a consensus. Pure forms of
synucleinopathies are unlikely sole substrates for dementia.
Copyright (C) 2008 S. Karger AG, Basel