Vascular parkinsonism--an important cause of parkinsonism in older people.

Parkinsonism due to cerebrovascular disease (vascular parkinsonism, VP) is a distinct clinicopathological entity. It accounts for 4.4-12% of all cases of parkinsonism. Since there are no specific diagnostic criteria, true incidence and prevalence rates of VP are not known. Typically, parkinsonism in slow-onset VP tends to be bilaterally symmetrical, affecting the lower limbs more than the upper limbs ('lower-body parkinsonism'), and resting tremor is usually absent. Commonly noted lesions on brain imaging in VP are lacunes, white matter changes and, rarely, territorial infarcts. As coincidental vascular lesions in idiopathic Parkinson's disease (PD) are common, the mere presence of these lesions on brain imaging is not diagnostic of VP. Pathological evidence of a vascular disease in the absence of typical PD lesions (e.g. Lewy bodies) is the diagnostic 'gold standard'. VP is generally considered to be poorly or non-responsive to L-dopa therapy. However, recent studies have shown a beneficial effect of L-dopa in a subset of patients. Despite great advances in overall understanding of the disease, there are several gaps in our knowledge.