Cerebrovascular disease, beta-amyloid, and cognition in aging

The present study evaluated cerebrovascular disease (CVD), beta-amyloid (A beta), and cognition in clinically normal elderly adults. Fifty-four participants underwent magnetic resonance imaging (MRI,), Pittsburgh compound 13 (PIB) position emission tomography (PET) imaging, and neuropsychological evaluation. High white matter hyperintensity burden and/or presence of infarct defined CVD status (CVD-: n = 27; CVD+: n = 27). PIB-positron emission tomography ratios of A beta deposition were extracted using Logan plotting (cerebellar reference). Presence of high levels of A beta in prespecified regions determined PIB status (PIB-: n = 33; PIB+: n = 21). Executive functioning and episodic memory were measured using composite scales. CVD and A beta, defined as dichotomous or continuous variables, were unrelated to one another. CVD+ participants showed lower executive functioning (p = 0.001) when compared with CVD- individuals. Neither PIB status nor amount of A beta affected cognition (ps >= 0.45), and there was no statistical interaction between CVD and PIB on either cognitive measure. Within this spectrum of normal aging CVD and A beta aggregation appear to he independent processes with CVD primarily affecting cognition. (C) 2012 Elsevier Inc. All rights reserved.