It is important to understand functional differences between dementia and non‐dementia of AD to predict progression forward to dementia at prodromal or preclinical stage of AD.
Alzheimer’s disease (AD) is the most common cause of dementia. However, accumulation of beta amyloid plague in the brain which is main pathology of AD could show the various spectrum of cognitive functional stage from preclinical level to overt dementia. It is important to understand functional differences between dementia and non‐dementia of AD to predict progression forward to dementia at prodromal or preclinical stage of AD.