Cerebral small vessel disease: how does it progress?

Small vessel disease (SVD), or microangiopathy, of the cerebral white and central grey matter is an important subtype of vascular dementia (VD). SVD-dementia is characterised by a "dysexecutive" type of cognitive impairment, neurological deficits including imbalance and voiding dysfunction, and emotional disturbances. SVD is also frequent among clinically healthy subjects and patients with mild cognitive impairment. It is easily visualised by imaging techniques, but difficult to distinguish from mixed SVD/Alzheimer Disease. SVD has an inherent tendency to progress, but data on its natural course are sparse, and there are almost no drug trials dedicated to it. This article reviews the evidence on the speed and predictors of progression of SVD in regard to cognitive deficits, functional decline and white matter lesions, as derived from epidemiological, clinical and imaging studies and the placebo branches of VD drug trials. Based on the available data, we make suggestions for future research and outcome measures.