Model-based ordering of the ALPS index among Alzheimer's disease biomarkers.

Glymphatic dysfunction has been implicated in Alzheimer's disease (AD), but its position relative to amyloid and tau biomarkers remains unclear. We examined the relative position of the diffusion tensor image analysis along the perivascular space (ALPS) index within the AD biomarker cascade using Alzheimer's Disease Neuroimaging Initiative data. Amyloid PET, tau PET, plasma amyloid-β 42/40 ratio, plasma phosphorylated-tau 217, and ALPS index were analyzed with a data-driven event-based model. The ALPS index was ranked between plasma amyloid-β 42/40 alteration and amyloid PET positivity in the model-based ordering of biomarker detectability, preceding tau-related biomarkers in the estimated sequence.