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

Abstract

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 Ͻ27 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,). 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-ThisJapanese 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.)Key Words: microbleeds Ⅲ cognitive impairment Ⅲ hypertension Ⅲ cerebral amyloid angiopathy B rain microbleeds (MBs) on gradient-echo T2*-weighted magnetic resonance imaging (MRI), which are characterized histologically by the presence of hemosiderin around small vessels, are now accepted as a manifestation of cerebral small vessel pathologies, including hypertensive small vessel disease and cerebral amyloid angiopathy (CAA). 1,2 MBs are often detected in patients with stroke, 2,3 and are also reportedly associated with dementia disorders such as Alzheimer's disease, 4 and vascular dementia, 5 or memory loss, 6 as well as cognitive decline. 7-11 However, their pathological impacts on cognitive function remain uncertain.The pathological differences in MBs according to distribution is now well-known, with MBs in deep regions (deep MBs) considered to be associated with hypertensive microangiopathy, whereas strictly lobar MBs (lobar MBs) share risk factors with CAA. 12,13 According to this pathological and distributional concept, we assessed whether different effects on global cognitive function might be seen with different topographical distributions of MBs in a sample of independen...

Strictly Lobar Cerebral Microbleeds Are Associated With Cognitive Impairment

“…[22][23][24]29,30 Some studies report that deep CMBs, 22,23 particularly those in the BG, are associated with cognitive decline, whereas others 29,30 report that lobar CMBs are associated with deficits in cognitive performance, which is in line with our results. Differences in population-based cohorts may explain why deep or lobar locations of MBs appear more prominently in different studies.…”

“…23,41,42 The present study evaluated whether CMBs and their locations were associated with a variety of cognitive domains. In addition, we used susceptibility weighted imaging on a 3T MRI, which is a tool with better resolution and higher sensitivity, 8 to detect CMBs.…”

“…The results indicate that there is no association between DI CMBs and cognitive function. Because previous studies have shown that BG CMBs are associated with cognitive deficits, 22,23 we tested the BG region separately. The results indicated that there is no correlation between BG CMBs and performance in any of the cognitive domains after adjusting for age, sex, and years of education (data not shown).…”

Ischemic brain injury in cerebral amyloid angiopathy

“…Although lobar microbleeds have found to be more common in patients with dementia than controls, [101][102][103][104] their causal relationship with cognition seems relatively weak. Several population-based and memory clinic studies found no association between the presence or number of lobar microbleeds and cognitive performance 78,102,[104][105][106][107] or global cognitive decline. 108,109 Positive associations between microbleeds and worse cognition are mainly found in individuals with a high MB count (>5 or >7) 110,111 or individuals diagnosed with symptomatic SVD.…”

Relationship Between Radiation Dose and Microbleed Formation in Patients With Malignant Glioma

“…CMBs have also been observed in elderly patients without known underlying pathology [13,14], as well as in other degenerative central nervous system conditions, including cerebral amyloid angiopathy (CAA) associated with Alzheimer's disease and vascular cognitive impairment [11], where they have been linked to cognitive dysfunction [15][16][17][18]. Thus, quantification of CMB characteristics may serve as a valuable metric for radiation-induced vasculopathy and resultant cognitive decline.…”