Cerebral Microbleeds Are Associated with Worse Cognitive Function in the Nondemented Elderly with Small Vessel Disease

BACKGROUND: Cerebral small vessel disease (SVD) is a leading cause of cognitive decline in the elderly. Cerebral microbleeds (CMBs) have emerged as an important manifestation of cerebral SVD, in addition to lacunar infarcts and white matter lesions (WMLs). We investigated whether the presence and location of CMBs in elderly subjects were associated with cognitive function, independent of lacunar infarcts and WMLs. METHODS: One hundred and forty-eight nondemented elderly with SVD, defined as the presence of lacunar infarcts and/or WMLs on magnetic resonance imaging (MRI), were studied. Executive function and global cognition were assessed by the Frontal Assessment Battery (FAB) and Mini-Mental State Examination (MMSE), respectively. The differences in the scores for the FAB and MMSE between CMB-positive and CMB-negative subjects were calculated after adjusting for possible confounders. RESULTS: The mean age of the subjects was 72.4 ± 8.6 years. CMBs were detected in 48 subjects (32%), with a mean number of CMBs per subject of 1.6 (range 0-31). Among CMB-positive subjects, 42 (87.5%) had CMBs in deep or infratentorial regions with or without lobar CMBs, and 6 (12.5%) had CMBs in strictly lobar regions. The presence of CMBs was significantly associated with FAB and MMSE scores after adjustment for age, years of education, brain volume and the presence of lacunar infarcts (for the FAB) or severe WMLs (for the MMSE). The presence of CMBs in the basal ganglia, in the thalamus or in the lobar regions was associated with FAB scores, while that in the lobar regions was associated with MMSE scores. However, there was no association between CMBs in the infratentorial regions and cognitive parameters. CONCLUSIONS: In nondemented elderly with SVD on MRI, the presence of CMBs was independently associated with worse executive and global cognitive functions. CMBs seemed to reflect hypertensive microangiopathy in this population, and CMBs in specific areas may play an important role in cognitive function.