Cerebral Microbleeds and Cognition

Cerebral microbleeds (CMBs) are considered to be a novel marker of cerebral small vessel disease. However, the link with cognitive impairment remains unclear. We investigated whether CMBs—independent of other traditional markers of cerebral small vessel disease—are related to cognition. Chinese subjects from the population-based Singapore Chinese Eye Study, who failed an initial cognitive screening and were recruited into the ongoing Epidemiology of Dementia in Singapore Study, underwent neuropsychological testing and 3 T brain magnetic resonance imaging. The presence and number of CMBs were graded using Brain Observer Microbleed Scale on susceptibility-weighted images. Other magnetic resonance imaging lesions that were graded included presence of lacunes, white matter lesion, and total brain volumes. A comprehensive neuropsychological battery was administered and cognitive function was summarized as composite and domain-specific Z-scores. Among 282 subjects, 91 had any CMBs (32.3%), of whom 36 (12.8%) had multiple CMBs. CMBs were—independent of cardiovascular risk factors and other markers of cerebral small vessel disease—significantly associated with poorer cognitive function as reflected by composite Z-score (mean difference per CMB increase: −0.06; 95% confidence interval: −0.11, −0.01] and with domain-specific Z-scores including executive function, attention, and visuoconstruction. Among Chinese subjects CMBs were, independent of other concomitant markers of cerebral small vessel disease, associated with poorer cognitive function.