Abstract 2858: Topographical Distribution of Brain Microbleeds and Global Cognitive Function in Adults without Neurological Disorders

Background and Purpose: Brain microbleeds (MBs) have been recognized to be associated with cognitive decline, and can be pathologically and topographically divided into cerebral amyloid angiopathy (CAA)-related MBs (lobar MBs) and hypertensive vasculopathy-related MBs (deep or infratentorial MBs). We assessed the hypothesis that different effects on global cognitive function might be seen with different topographical distributions of MBs. Methods: A total of 1278 consecutive adults (mean age, 58 years) without neurological disorders who had undergone health-screening tests of the brain were studied prospectively. Gradient-echo T2*-weighted MRI using a 1.5-T system was used to detect MBs. Subjects were divided into four groups: without MBs; with lobar MBs; with MBs in deep or infratentorial areas (deep MBs); and with MBs in both areas (diffuse MBs). The Mini-Mental State Examination (MMSE) was administered to determine cognitive functions. MMSE scores Results: MBs were detected in the brain for 98 of 1279 subjects (8%), including 36 subjects (3%) with lobar MBs, 48 (4%) with deep MBs, and 14 (1%) with diffuse MBs. Subnormal MMSE scores were found in 76 subjects (6%), and were significantly associated with higher age, higher systolic blood pressure, shorter duration of education, severe white matter hyperintensities, and presence of MBs. After adjusting for these related factors, presence of any MBs (odds ratio (OR), 2.29; 95% confidence interval (CI), 1.17-4.46), and topographical distributional patterns of deep MBs (OR, 2.86; 95%CI, 1.20-6.78) and diffuse MBs (OR, 5.72; 95%CI, 1.59-20.54) were significantly associated with subnormal MMSE score, whereas lobar MBs were not (OR, 0.79; 95%CI, 0.18-3.47). Scores for total MMSE and “attention and calculation” were significantly lower with deep MBs ( P P Conclusions: Regarding the presence of any MBs, hypertensive vasculopathy-related MBs appear to be the main cause of global cognitive dysfunction in neurologically healthy adults. In most middle-aged subjects, effects of CAA-related MBs on cognitive function might not yet be apparent.