MAPT and Alzheimer disease: In a push to detect the earliest cognitive changes associated with AD, two validation studies of DCTclock on patients with preclinical AD showed significant association of DCTclock measures with both amyloid and tau PET imaging markers; the first study also showed significant association with the Preclinical Alzheimer's Cognitive Composite (24), while the second demonstrated the ability to further tailor the DCTclock algorithm to improve detection of Alzheimer's pathology (25).