Criteria
There are three sets of criteria for the clinical diagnoses of the spectrum of Alzheimer's disease: the 2013 fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5); the National Institute on Aging-Alzheimer's Association (NIA-AA) definition as revised in 2011; and the International Working Group criteria as revised in 2010.[31][116] Three broad time periods, which can span decades, define the progression of Alzheimer's disease from the preclinical phase, to mild cognitive impairment (MCI), followed by Alzheimer's disease dementia.[118]

Eight intellectual domains are most commonly impaired in AD—memory, language, perceptual skills, attention, motor skills, orientation, problem solving and executive functional abilities, as listed in the fourth text revision of the DSM (DSM-IV-TR).[119]