MAPT and Mental deterioration: In this group, 93% were concurrently amyloid PET‐positive with rather high amyloid burden (median centiloid of 75.9) and rather pronounced cognitive decline from non‐symptomatic or mildly impaired baseline that differed in rate of declining trajectory from the other tau groups and in the number of transitions to cognitive impairment by the time of the most recent evaluation (20% had MCI at cognitive baseline, while 51% were diagnosed with MCI or dementia at the most recent cognitive exam).