Labile BP, cerebral small vessel disease, and neurodegeneration. Mounting evidence suggest that high and abnormally labile BP causes cerebral small vessel disease with resulting ischemia and activation of neuroinflammatory mechanisms that contribute to the accumulation and spread of misfolded proteins (tau, β‐amyloid, α‐synuclein), accelerating neuronal loss and cognitive decline in Alzheimer's disease and in the synucleinopathies (Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, pure autonomic failure). BP, blood pressure; CNS, central nervous system.