Strictly Lobar Cerebral Microbleeds Are Associated With Cognitive Impairment

Abstract

2 In addition to being an age-related cerebrovascular abnormality, [3][4][5] CMBs are associated with dementia. The prevalence of CMBs is reported to be higher in patients with Alzheimer's disease (AD) and vascular dementia compared with the general population. 6 The mechanisms underlying CMBs and their effects on neuropsychological functions are subjects of active research.CMB in different locations might be related to different clinical manifestations. 3,7,8 The incidence of both CMB types increases with age. However, deep or infratentorial (DI) and strictly lobar (SL) CMBs have different risk factors. DI and SL CMBs are correlated with hypertension and APOE ɛ4 genotype, respectively. Therefore, DIs are usually attributed to hypertension vasculopathy, and SL CMBs are attributed to cerebral amyloid angiopathy (CAA). 3,7,8 The effects of CMBs on cognitive function in the general population have been evaluated in previous studies. However, there are inconsistent results regarding the location of CMBs that are associated with cognitive loss. In addition, only a few Asian CMB studies have evaluated the effects of CMBs on different cognitive domains. Therefore, the present study aimed to study the possible Background and Purpose-Different distributions of cerebral microbleeds (CMBs) are associated with distinct pathological mechanisms. Lobar CMBs are thought to be related to cerebral amyloid angiopathy, whereas deep or infratentorial CMBs are related to hypertensive vasculopathy. The present study aimed to evaluate the effects of CMBs and their locations on a variety of cognitive domains. Methods-Study subjects were selected from the community-based I-Lan Longitudinal Aging Study. We assessed cognitive domains, including verbal memory, language, visuospatial executive function, and verbal executive function. CMBs were evaluated using 3T susceptibility-weighted magnetic resonance imaging. Results-We studied 959 subjects (mean±SD, 62.5±8.6 years; 425 [44.3%] men). CMBs were found in 14.2% of the population. We classified subjects with CMBs into 2 different groups based on the locations of their CMBs: (1) deep or infratentorial (85 subjects, 8.8% of population) and (2) strictly lobar (49, 5.1%). Multivariate linear analysis showed that strictly lobar CMBs were significantly associated with deficits in global cognitive function (Mini-Mental State Examination) and visuospatial executive function, as determined by the copy test of the Taylor complex figure test and the clock drawing test. We adjusted our results for age, sex, years of education, cardiovascular risk factors, and other markers of cerebral small vessel disease, lacunes, and white matter hyperintensity. Deep or infratentorial CMBs were not associated with changes in cognitive function in our population. Conclusions-Strictly lobar, but not deep or infratentorial, CMBs are associated with changes in cognitive function, especially in visuospatial executive functions. Cerebral amyloid angiopathy may be the underlying pathology associated with CMB-related cognitiv...

Prevalence of and risk factors for cerebral microbleeds among adult patients with haemophilia A or B

“…Although their clinical significance continues to be assessed, data from population‐based cohort studies show that CMBs are associated with increased risk of both future ischaemic stroke (IS) and intracerebral haemorrhage (ICH), recurrent IS and ICH, and both cardiovascular‐related and all‐cause mortality . Emerging data suggest CMBs are associated with reduced global cognitive function and both vascular and all‐cause dementia …”

Cerebral microbleeds and risk of incident dementia: the Framingham Heart Study

“…(Chung et al, 2016) It is also conceivable that disruption of cortico-nigrostriatal and thalamo-cortical pathways by strategically placed deep/mixed CMBs could contribute to cognitive decline.…”

Background and distribution of lobar microbleeds in cognitive dysfunction

“…Few previous studies have described regional distribution of lobar CMBs. A community-based study using SWI on 3T-MRI showed that the occipital lobe had the most numerous CMBs followed by the T A B L E 2 Three-group comparison: SL-CMBs·M-CMBs·D-CMBs frontal lobe (Chung et al, 2016). In patients with AD, CMBs have been found to be most numerous in the occipital lobe, followed by the temporal lobe, in studies using T2* on 1.5T-MRI (Pettersen et al, 2008) or SWI on 3T-MRI (Uetani et al, 2013).…”