Vascular Parkinsonism: deconstructing a syndrome.

Area of Science:

• Neurology
• Neuroimaging
• Movement Disorders

Background:

• Vascular parkinsonism (VaP) is diagnosed based on progressive ambulatory impairment and white matter (WM) abnormalities on neuroimaging.
• Current literature suggests limitations in the diagnostic specificity of imaging findings for VaP.

Purpose of the Study:

• To critically appraise the literature regarding the diagnostic criteria and specificity of neuroimaging in vascular parkinsonism.
• To differentiate true vascular parkinsonism from conditions with overlapping clinical and imaging features.

Main Methods:

• Literature review and critical appraisal of existing clinicopathologic and neuroimaging studies related to vascular parkinsonism.
• Analysis of the correlation between brain MRI hyperintensities, microangiopathic disease, and parkinsonism.

Main Results:

• No specific structural imaging pattern is definitively associated with VaP.
• Poor correlation exists between MRI white matter hyperintensities and the presence of microangiopathic brain disease and parkinsonism.
• Definite vascular parkinsonism results from specific stroke locations (SN/nigrostriatal pathway) sparing certain brain regions.
• Many reported VaP cases may represent pseudovascular parkinsonism (e.g., Parkinson's disease, PSP), vascular pseudoparkinsonism (e.g., akinetic mutism), or pseudovascular pseudoparkinsonism (e.g., NPH).

Conclusions:

• The term vascular parkinsonism (VaP) should be used cautiously until pathology or validated biomarkers confirm the diagnosis.
• Alternative syndromic designations are recommended for cases with nonspecific neuroimaging findings to avoid misdiagnosis.
• Distinguishing VaP from other parkinsonian disorders and gait disturbances based solely on neuroimaging is challenging.