Dementia in Parkinson disease Functional imaging of cholinergic and dopaminergic pathways

Objective: To assess neurochemical deficits in patients with Parkinson disease (PD) associated dementia (PDD) in vivo. Methods: The authors performed combined PET with N -[ 11 C]-methyl-4-piperidyl acetate (MP4A) and 18 F-fluorodopa (FDOPA) for evaluation of cholinergic and dopaminergic transmitter changes in 17 non-demented patients with PD and 10 patients with PDD. Data were compared to 31 age-matched controls by a combined region-of-interest and voxel-based Statistical Parametric Mapping analysis. Results: The striatal FDOPA uptake was significantly decreased in PD and PDD without differences between the groups. The global cortical MP4A binding was severely reduced in PDD (29.7%, p p Conclusions: While non-demented patients with Parkinson disease had a moderate cholinergic dysfunction, subjects with Parkinson disease associated dementia (PDD) presented with a severe cholinergic deficit in various cortical regions. The finding of a closely associated striatal FDOPA and cortical MP4A binding reduction suggests a common disease process leading to a complex transmitter deficiency syndrome in PDD.