Mechanisms of Cognitive Impairment in Cerebral Small Vessel Disease: Multimodal MRI Results from the St George's Cognition and Neuroimaging in Stroke (SCANS) Study

Abstract

Cerebral small vessel disease (SVD) is a common cause of vascular cognitive impairment. A number of disease features can be assessed on MRI including lacunar infarcts, T2 lesion volume, brain atrophy, and cerebral microbleeds. In addition, diffusion tensor imaging (DTI) is sensitive to disruption of white matter ultrastructure, and recently it has been suggested that additional information on the pattern of damage may be obtained from axial diffusivity, a proposed marker of axonal damage, and radial diffusivity, an indicator of demyelination. We determined the contribution of these whole brain MRI markers to cognitive impairment in SVD. Consecutive patients with lacunar stroke and confluent leukoaraiosis were recruited into the ongoing SCANS study of cognitive impairment in SVD (n = 115), and underwent neuropsychological assessment and multimodal MRI. SVD subjects displayed poor performance on tests of executive function and processing speed. In the SVD group brain volume was lower, white matter hyperintensity volume higher and all diffusion characteristics differed significantly from control subjects (n = 50). On multi-predictor analysis independent predictors of executive function in SVD were lacunar infarct count and diffusivity of normal appearing white matter on DTI. Independent predictors of processing speed were lacunar infarct count and brain atrophy. Radial diffusivity was a stronger DTI predictor than axial diffusivity, suggesting ischaemic demyelination, seen neuropathologically in SVD, may be an important predictor of cognitive impairment in SVD. Our study provides information on the mechanism of cognitive impairment in SVD.

Longitudinal change of small-vessel disease-related brain abnormalities

“…73 Further, correlations of diffusion parameters in patients with small-vessel disease and cognitive outcome measures (e.g., memory, psychomotor speed, concept shifting, and attention) were also found to be significant. [74][75][76][77] Table 6 gives an overview of longitudinal studies reporting sensitivity of the measures in normal-appearing brain tissue in younger, middle, and older-aged elderly subjects.…”

Immunopathogenetic Aspects of Ischemic Stroke

“…Учитывая, что миели-низация нервных волокон играет важную роль в обеспечении двигательной активности и ней-ропластичности [83], аутоиммунное поврежде-ние миелина может негативно влиять на восста-новление после инсульта, обусловливая развитие когнитивных расстройств и церебральной атро-фии [64]. Действительно, Becker K.J.…”

[P1–450]: Diffusion Tensor Image Segmentation of the Cerebrum Provides a Single Measure of Cerebral Small‐vessel Disease Severity Related to Cognitive Change

“…Recruitment occurred between 2007 and 2010 at three stroke services in hospitals covering a geographically contiguous area in South London, UK; St George's Hospital, King's College Hospital and St Thomas' Hospital. This data set has been described previously Lambert et al, 2015;Lawrence et al, 2013;Zeestraten et al, 2016). Inclusion criteria comprised of a clinical lacunar stroke syndrome (Bamford et al, 1987) with radiological evidence of an anatomically corresponding lacunar infarct <=1.5 cm diameter.…”

“…No group comparisons between healthy ageing and SVD patients were performed in this study. For group comparisons see Lawrence et al (2013) where it was reported that there were no differences in age or gender between the SCANS and GENIE cohorts.…”

“…Higher rates of atrophy are associated with increased decline in EF and IPS over a 3-year period . WMH and lacunar infarcts have also been associated with cognitive difficulties in SVD (Benisty et al, 2009;Benjamin et al, 2015;van den Heuvel et al, 2006;Lawrence et al, 2013;Schmidt et al, 2012). CMB have demonstrated a weak association with EF in SVD Yamashiro et al, 2014).…”