Progressive ambulatory impairment and abnormal white matter (WM) signal on neuroimaging come together under the diagnostic umbrella of vascular
parkinsonism (VaP). A critical appraisal of the literature, however, suggests that (1) no abnormal structural imaging pattern is specific to VaP; (2) there is poor correlation between brain MRI hyperintensities and microangiopathic
brain disease and
parkinsonism from available clinicopathologic data; (3) pure
parkinsonism from
vascular injury ("definite" vascular
parkinsonism) consistently results from ischemic or
hemorrhagic strokes involving the SN and/or nigrostriatal pathway, but sparing the striatum itself, the cortex, and the intervening WM; and (4) many cases reported as VaP may represent pseudovascular
parkinsonism (e.g.,
Parkinson's disease or another neurodegenerative
parkinsonism, such as PSP with nonspecific neuroimaging signal abnormalities), vascular pseudoparkinsonism (e.g.,
akinetic mutism resulting from bilateral mesial frontal
strokes or apathetic depression from bilateral striatal
lacunar strokes), or pseudovascular pseudoparkinsonism (e.g., higher-level gait disorders, including
normal-pressure hydrocephalus with transependimal exudate). These syndromic designations are preferable over VaP until pathology or validated
biomarkers confirm the underlying nature and relevance of the
leukoaraiosis. © 2015 International Parkinson and
Movement Disorder Society.