MAPT and Parkinson disease: Furthermore, after adjustment for age and sex, multiple regression models for cognitive impairment in PD patients revealed Aβ-40 (OR = 0.921, 95%CI = 0.879–0.964), T-tau (OR = 3.016, 95%CI = 1.703–5.339), and α-synuclein (OR = 1.069, 95%CI = 1.026–1.115) to be independently associated with cognitive impairment in patients with PD.