The role of age on tau PET uptake and gray matter atrophy in atypical Alzheimer's disease

Abstract

IntroductionLittle is known about the role of age on neurodegeneration and protein deposition in atypical variants of Alzheimer's disease (AD). MethodsRegional tau and β-amyloid positron emission tomography standard uptake value ratios and gray matter volumes were calculated in a cohort of 42 participants with atypical AD. The relationship between regional metrics and age was modeled using a Bayesian hierarchical linear model. ResultsAge was strongly associated with tau uptake across all cortical regions, particularly parietal, with greater uptake in younger participants. Younger age was associated with smaller parietal and lateral temporal volumes. Regional β-amyloid differed little by age. Age showed a stronger association with tau than volume and β-amyloid in all cortical regions. Age was not associated with cognitive performance. DiscussionAge is an important determinant of severity of cortical tau uptake in atypical AD, with young participants more likely to show widespread and severe cortical tau uptake.