MAPT and Alzheimer disease: While previous studies demonstrated the temporal relationship of amyloid, tau, and cognition,2 the utility of the AT(N) framework in predicting AD status in DS,26 and the relationship between AT(N) plasma biomarkers and cognition27; this is the first study to incorporate longitudinal changes within the full AT(N) framework and to include ChBF atrophy as an alternate measure of neurodegeneration.