Tauopathy in basal ganglia involvement is exacerbated in a subset of patients with Alzheimer's disease: The Hisayama study

INTRODUCTION: We have conducted the pathological cohort study of autopsied cases of Hisayama residents to reveal a recent trend of dementia-related pathology. We noticed a trend of putaminal involvement of Alzheimer's disease (AD) with parkinsonism. Then, we investigated the accurate prevalence of neurological diseases with putaminal AD pathology in the general population. METHODS: We examined a series of 291 autopsies in the Hisayama study and performed image analysis of immunohistochemistry for microtubule-associated protein tau (MAPT) and amyloid β. RESULTS: Approximately 65.6% and 36.1% of cases showed putaminal MAPT and amyloid deposits, respectively. Diffuse deposits of them were mainly found in the AD cases. Putaminal MAPT was highly associated with AD-related pathological criteria. Four of 22 cases with severe putaminal MAPT deposition were documented as having developed parkinsonism. DISCUSSION: Severe MAPT accumulation in the basal ganglia was closely related to the development of AD pathology and could occur most frequently in AD cases without comorbidities.