Shah_2016_Mov.Disord_31_111

INTRODUCTION: Although most previous cognitive studies of beta-amyloidopathy in PD focused on cortical plaque deposition, recent postmortem studies point to an important role of striatal beta-amyloid plaque deposition. The aim of this study was to investigate the relative contributions of striatal and cortical beta-amyloidopathy to cognitive impairment in PD.
METHODS: Patients with PD (n = 62; age, 68.9 +/- 6.4 years; H & Y stage: 2.7 +/- 0.5; MoCA score: 25.2 +/- 3.0) underwent [(11) C]Pittsburgh compound B beta-amyloid, [(11) C]dihydrotetrabenazine monoaminergic, and [(11) C]methyl-4-piperidinyl propionate acetylcholinesterase brain PET imaging and neuropsychological assessment. [(11) C]Pittsburgh compound B beta-amyloid data from young to middle-aged healthy subjects were used to define elevated [(11) C]Pittsburgh compound B binding in patients.
RESULTS: Elevated cortical and striatal beta-amyloid deposition were present in 37% and 16%, respectively, of this predominantly nondemented cohort of patients with PD. Increased striatal beta-amyloid deposition occurred in half of all subjects with increased cortical beta-amyloid deposition. In contrast, increased striatal beta-amyloid deposition did not occur in the absence of increased cortical beta-amyloid deposition. Analysis of covariance using global composite cognitive z scores as the outcome parameter showed significant regressor effects for combined striatal and cortical beta-amyloidopathy (F = 4.18; P = 0.02) after adjusting for covariate effects of cortical cholinergic activity (F = 5.67; P = 0.02), caudate nucleus monoaminergic binding, duration of disease, and age (total model: F = 3.55; P = 0.0048). Post-hoc analysis showed significantly lower cognitive z score for combined striatal and cortical beta-amyloidopathy, compared to cortical-only beta-amyloidopathy and non-beta-amyloidopathy subgroups.
CONCLUSIONS: The combined presence of striatal and cortical beta-amyloidopathy is associated with greater cognitive impairment than cortical beta-amyloidopathy alone in PD. (c) 2015 International Parkinson and Movement Disorder Society.