Mixed-location cerebral microbleeds as a biomarker of neurodegeneration in a memory clinic population

Cerebral microbleeds (CMBs) in the lobar and deep locations are associated with two distinct pathologies: cerebral amyloid angiopathy and hypertensive arteriopathy. However, the role of mixed-location CMBs in neurodegeneration remains unexplored. We investigated the associations between strictly lobar, strictly deep and mixed-location CMBs with markers of neurodegeneration. This study recruited 477 patients from a memory clinic who underwent 3T MRI scans. CMBs were categorized into strictly lobar, strictly deep and mixed-location. Cortical thickness, white matter volume and subcortical structural volumes were quantified using Free-Surfer. Linear regression models were performed to assess the association between CMBs and cerebral atrophy, and the mean difference (β) and 95% confidence intervals (CIs) were reported. In the regression analyses, mixed-location CMBs were associated with smaller cortical thickness of limbic region [β=-0.01; 95% CI=-0.02,-0.00, p=0.007) as well as with smaller accumbens volume [β=-0.01; 95% CI=-0.02,-0.00, p=0.004) and presubiculum region of hippocampus [β=-0.01; 95% CI=-0.02,-0.00, p=0.002). Strictly lobar CMBs were associated with smaller total white matter volume [β=-0.03; 95% CI=-0.04,-0.01, p<0.001] and with region specific white mat

Interethnic differences in neuroimaging markers and cognition in Asians, a population-based study

We examined interethnic differences in the prevalence of neuroimaging markers of cerebrovascular and neurodegenerative disease in 3 major Asian ethnicities (Chinese, Malays, and Indians), as well as their role in cognitive impairment. 3T MRI brain scans were acquired from 792 subjects (mean age: 70.0 ± 6.5years, 52.1% women) in the multi-ethnic Epidemiology of Dementia In Singapore study. Markers of cerebrovascular disease and neurodegeneration were identified. Cognitive performance was evaluated using Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and a neuropsychological assessment. Compared to Chinese, Malays had a higher burden of intracranial stenosis (OR: 2.28. 95%CI: 1.23-4.20) and cortical atrophy (β: -0.60. 95%CI: -0.78, -0.41), while Indians had a higher burden of subcortical atrophy (β: -0.23. 95%CI: -0.40, -0.06). Moreover, Malay and Indian ethnicities were likely to be cognitively impaired (OR for Malays: 3.79. 95%CI: 2.29-6.26; OR for Indians: 2.87. 95%CI: 1.74-4.74) and showed worse performance in global cognition (β for Malays: -0.51. 95%CI: -0.66, -0.37; and Indians: -0.32. 95%CI: -0.47, -0.17). A higher burden of cerebrovascular and neurodegenerative markers were found in Malays and Indians when compared to Chinese. Further research is required to fully elucidate the factors and pathways that contribute to these observed differences