MAPT and Cognitive impairment: In a later publication, Schwarz et al. [30] used the tau PET tracer flortaucipir in the ADNI cohort, including 46 cognitively unimpaired participants [19 amyloid-positive], 42 mild cognitive impairment (MCI) participants [24 amyloid-positive], and 10 AD dementia participants [9 amyloid-positive].