Abstract
Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease. In humans, AD becomes symptomatic only after brain changes occur over years or decades. Three contiguous phases of AD have been proposed: (i) the AD pathophysiologic process, (ii) mild cognitive impairment due to AD, and (iii) AD dementia. Intensive research continues around the world on unique diagnostic markers and interventions associated with each phase of AD. In this review, we summarize the available evidence and new therapeutic approaches that target both amyloid and tau pathology in AD and discuss the biomarkers and pharmaceutical interventions available and in development for each AD phase.