Associations between misfolded alpha-synuclein aggregates and Alzheimer's disease pathology in vivo.

Amyloid beta (Aβ), but not tau, was associated with alpha-synuclein (α-synuclein) positivity. Such association was consistent across two cohorts, beyond the effect of age, sex, and cognitive status. α-synuclein-positive participants had a small, statistically significant faster increase in Aβ positron emission tomography levels in one of the two cohorts.