The L-dopa response in vascular parkinsonism

Objective: To determine whether a positive L-dopa response in vascular parkinsonism (VP) is correlated with the presence of nigrostriatal pathology due to either vascular damage or neuronal cell loss. Methods: Seventeen patients with pathologically confirmed VP were selected from the pathological collection of the Queen Square Brain Bank for Neurological Disorders, and their L-dopa response during life was compared with the presence of macroscopic vascular damage in the nigrostriatal pathway and microscopic substantia nigra cell loss. Results: Ten of the twelve patients with a good or excellent response had macroscopic infarcts or lacunae caused by enlarged perivascular spaces in the basal ganglia or microscopic neuronal cell loss in the substantia nigra. In contrast, only one of the five patients with a moderate or no response had lacunae in the putamen, and none had lacunar infarcts or substantia nigra cell loss. Conclusion: These results suggest that a substantial number of patients with clinically suspected VP may respond with benefit to dopaminergic therapy, especially those with lesions in or close to the nigrostriatal pathway.