This practice guideline updates a 2001 American Academy of Neurology (AAN) practice parameter with recommendations concerning the diagnosis and treatment of MCI. The guideline focuses on presumed idiopathic or neurodegenerative MCI—particularly relating to Alzheimer's Disease (AD)—rather than mild cognitive changes relating to potentially reversible causes (e.g., metabolic, vascular, systemic, or psychiatric disorders) or Parkinson disease–MCI or vascular cognitive impairment, as these may have different epidemiologic and treatment spectra than AD.