Fig. 3.

Estimated biomarker trajectories as a function of time from initial AD dementia diagnosis are shown with the black curves, and the shaded areas depict 95% credible intervals. A value of 0 on the x-axis corresponds to the onset of AD dementia. Negative values are before the onset of AD dementia, and positive values are after the onset of AD dementia. Biomarker z-scores, shown on the right-hand-side y-axes, were computed using mean and standard deviations at baseline across 1369 individuals in the training set. Note that observed time from AD was not used in the estimation of the biomarker trajectories shown; trajectories were obtained using the model fit. Scattergrams of observations are shown as a function of observed time from AD, color-coded by diagnosis, to allow for a visual assessment of the agreement of the estimated trajectories with underlying data. Abbreviations: Aβ, amyloid β; CSF, cerebrospinal fluid; FDG, fluorodeoxyglucose; PET, positron emission tomography; RAVLT, Rey Auditory Verbal Learning Test; ADAS13, Alzheimer's Disease Assessment Scale-Cognitive 13-item scale; MMSE, Mini–Mental State Examination; CDR-SB, Clinical Dementia Rating-Sum of Boxes.