Abstract
INTRODUCTION: Primary age-related tauopathy (PART) is a recently described entity that can cause cognitive impairment in the absence of Alzheimer's disease (AD). Here, we compared neuropathological features, tau haplotypes, apolipoprotein E (APOE) genotypes, and cognitive profiles in age-matched subjects with PART and AD pathology. METHODS: Brain autopsies (n = 183) were conducted on participants 85 years and older from the Baltimore Longitudinal Study of Aging and Johns Hopkins Alzheimer's Disease Research Center. Participants, normal at enrollment, were followed with periodic cognitive evaluations until death. RESULTS: Compared with AD, PART subjects showed significantly slower rates of decline on measures of memory, language, and visuospatial performance. They also showed lower APOE ε4 allele frequency (4.1% vs. 17.6%, P = .0046). DISCUSSION: Our observations suggest that PART is separate from AD and its distinction will be important for the clinical management of patients with cognitive impairment and for public health care planning.