MAPT and Alzheimer disease: However, older amnestic AD patients over the age of 65 years can show very little cortical or medial temporal uptake on PET (Whitwell et al., 2018a; Figure 2) and the relationship between tau uptake and volume loss breaks down, with volume loss of the medial temporal lobe occurring in the absence of appreciable tau uptake (Josephs et al., 2020b), suggesting that other factors are contributing to this volume loss in elderly AD patients.