Distributional Impact of Brain Microbleeds on Global Cognitive Function in Adults Without Neurological Disorder

Background and Purpose-Brain microbleeds (MBs) are considered to be associated with cognitive decline and can be pathologically and topographically classified as cerebral amyloid angiopathy-related (located in lobar regions) and hypertensive microangiopathy-related (located in deep regions). We examined whether different effects on global cognitive function might be seen with different distributions of MBs. Methods-A total of 1279 adults without neurological disorders were studied prospectively. Subjects were divided into 4 groups: without-MBs group; lobar group; deep group; and with in both areas (diffuse group). The Mini-Mental State Examination was administered to determine global cognitive functions, with scores <27 regarded as subnormal. Results-MBs were detected in 98 subjects (8%): 36 subjects (3%) classified as lobar group, 48 subjects (4%) as deep group, and 14 subjects (1%) as diffuse group. Subnormal scores were found in 76 subjects (5.9%), associated with age, education, hypertension, severe white matter hyperintensities, and distribution and number of MBs. In the final model of logistic regression analysis, the deep group (OR, 2.79; 95% CI, 1.14-6.79) was associated with subnormal scores, whereas the lobar group (OR, 0.77; 95% CI, 0.17-3.44) was not. Trend for the diffuse group did not reach the level of significance (OR, 5.01; 95% CI, 0.88-28.41). These trends were also seen in analysis using another cut-off point for subnormal score. Scores for total Mini-Mental State Examination and attention and calculation were significantly lower in the deep group and the diffuse groups compared with the without-MBs group. Conclusions-This Japanese cross-sectional study demonstrated that MB-related global cognitive dysfunction seems to occur based on hypertensive pathogenesis rather than on cerebral amyloid angiopathy. (Stroke. 2012;43:1800-1805.)