The limbic and neocortical contribution of α-synuclein, tau, and amyloid β to disease duration in dementia with Lewy bodies.

INTRODUCTION: We sought to assess the individual and combined contribution of limbic and neocortical α-synuclein, tau, and amyloid β (Aβ) to duration of illness in dementia with Lewy bodies (DLB).

METHODS: Quantitative digital pathology of limbic and neocortical α-synuclein, tau, and Aβ was assessed in 49 patients with clinically probable DLB. Regression modeling examined the unique and shared contribution of each pathology to the variance of illness duration.

RESULTS: Patients with diffuse Lewy body disease had more severe pathology of each type and a shorter duration of illness than individuals with transitional Lewy body disease. The three pathologies accounted for 25% of the total variance of duration of illness, with 19% accounted for by α-synuclein alone or in combination with tau and Aβ. When the diffuse Lewy body disease group was examined separately, α-synuclein deposition significantly exceeded that of tau and Aβ. In this model, 20% of 24% total variance in the model for duration of illness was accounted for independently by α-synuclein.

DISCUSSION: In DLB, α-synuclein is an important predictor of disease duration, both independently and synergistically with tau and Aβ.