Employing the AIC and the adjusted R² variance (Adj R²), the model fits and the Adj R² of the Clinical model (Clinical: age and sex and education/premorbid IQ), the Clinical-DTI model (age and sex and education/premorbid IQ+MD median), the Clinical-MRI model (age and sex and education/premorbid IQ and BV and WMH and lacune count and CMB) and the Clinical-MRI-DTI model (age and sex and education/premorbid IQ & BV and WMH and lacune count and CMB and MD median) were compared. AIC was lowest (reflecting best model fit) for the DTI+MRI + clinical model in all single-centre SVD cohorts (SCANS, RUN DMC and CADASIL) indicating that this is the best model dealing with the trade-off between the goodness of fit of the model and the simplicity of the model. The multimodal MRI’s Adj R² ranged between 0.311 and 0.564 across the cohorts.

AIC, Akaike information criterion; BV, brain volume; CMB, cerebral microbleeds; DTI, diffusion tensor imaging; MD, mean diffusivity; Adj. R², adjusted R² variance; SVD, small vessel disease; WMH, white matter hyperintensities.