[Defining and disease-modifying therapy for the preclinical stages of Alzheimer's disease].

The pathophysiological process of Alzheimer's disease (AD) is thought to begin more than twenty years before the diagnosis of AD dementia. Recent studies provided the biomarker of AD pathological changes. Biomarkers of brain Aβ amyloidosis include reduction in cerebrospinal fluid (CSF) Aβ42 and increased amyloid tracer retention on positron emission tomography(PET) imaging. Elevated CSF tau is thought to be a biomarker of neuronal injury. The Natinal Institute on Aging and the Alzheimer's Association proposed AD dementia, mild cognitive impairment due to AD, the preclinical stage of AD. These recommendation for the biomarker of AD are intended for research purposes at this time. Some disease-modifying therapies may be effective for the preclinical stage of AD.