[Vascular parkinsonian syndrome].

The present review shows that vascular parkinsonian syndrome (VPS) fulfilling stringent diagnostic criteria for parkinsonism is a rare disease that cannot always be distinguished from neurodegenerative parkinsonism on clinical grounds. Thus VPS needs to be differentiated from other disturbances, which have distinct phenomenological and therapeutical features including isolated gait disturbances associated with subcortical arteriosclerotic encephalopathy and neurodegenerative parkinsonism complicated by comorbid vascular encephalopathy. Acute or subacute VPS is usually caused by contralateral infarctions involving the external globus pallidus, ventrolateral thalamus, and, less often, the substantia nigra. Chronic VPS with insidious onset is related to bilateral subcortical infarctions affecting thalamocortical projections. Differentiation from degenerative parkinsonism is difficult in cases of VPS that display a progressive course and response to levodopa.