Figure 1.

Relevant changes over time in AD. AD is characterized by increasing levels of Aβ plaque, followed by hyperphosphorylation and secretion of tau and subsequent neurodegeneration. These changes can be monitored using multiple readouts to help diagnose patients and distinguish between the prodromal (shown in left column) and symptomatic (shown in right column) stages of disease. PET imaging, CSF sampling, and blood draws are most commonly used in ongoing research to asses pathological changes in AD patients over the course of disease progression. Within each specified sampling compartment, arrows pointing up represent elevations in biomarkers that occur during pathology, while arrows pointing down represent declines in these biomarkers.